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Exordium
Welcome to the July 2006, 27th issue of Submarine Telecoms Forum, our Subsea Technologies edition.
We have some excellent articles for your consideration.
Gabriel Ruhan provides a cable technology snapshot, while Eyal Lichtman and Michael Schneider discuss repeaterless DWDM for submarine cables. Andrew Lipman and Ulises Pin describe system financing for the future, while Ray Chrisner outlines the evolution of smart branching units. Igor Czajkowski explains the theory and practice of system upgrades, as Dr. Merrion Edwards and Rita Rukosueva reveal ultra-lowloss fibers in submarine applications. Jean Devos returns with his ever-insightful observations, and of course, our ever popular “where in the world are all those pesky cableships” is included as well. Lastly, STF’s annual Author’s Index is included as a useful reference for past articles from some rather smart folks.
Happy reading.
Middle East
The oldest and traditional fiber optic route is via the Middle East, using the systems of Flag Euro Asia or SEA-ME-WE-3.
These two submarine systems were immensely significant developments at their time of construction. They are essentially branched systems designed to provide connectivity to large numbers of countries en route. Ring protected submarine systems in other oceans of the world were developed later and neither Flag nor SMW-3 are, in themselves, ring systems. Restoration of Flag and SMW-3 has to be created using support of capacity one from the other or from other, less immense systems which parallel some of the route.
above 3 options. If, for example, RTD is of optimum importance to the buyer, then the new additional option of routing via Russia, one would assume, will be of great interest.
on those segments of the route than there was two or three years ago.
Did you realise that the Global Marine image on our home page is 3.2Mb. Takes forever to load, but great for boosting traffic on submarine cables!
The RTD is circa 230 ms. Prices are quoted by various suppliers, offering a range of prices normally at least double those via USA/transPacific option.
-Stuart Corner
Spectacular job putting this together...it’s very impressive.
Future price movements, by nature, are of course very difficult to predict. The USD 35 000 represents a small reduction on prices over the past 12 months. Price reduction in the last year has been small compared with the annual reduction of circa 50 % p.a. that has been recorded over previous years. We can but hope that prices across the Atlantic, across continental USA and across the Pacific have now stabilised. As regards the trends in prices on the route via the Middle East, the prices of Europe-Asia capacity following that route have declined less dramatically over the previous five years yet we can see nothing to cause upward pressure on prices on that route.
The likely trend in prices of capacity on the route via Russia and Mongolia is very hard to predict. There are relatively few suppliers capable of provisioning end-to-end circuits and therefore the intensity of competition is not as great as either of the other routes. The existence of the other routes nevertheless should continue to act as a downward pressure on prices on the shortest route.
It is obviously apparent that the buyer’s criteria will decide which route to use from the
Spectacular job putting this together...it’s very impressive.
Dr. William J. Barattino, Global Broadband Solutions, LLC
Indeed, with new cables opening up between India and Singapore and onward to Eastern Asia, there is now a lot more competition
The growth of predicted traffic to China over the coming years is well known. Indeed China Telecom is pro-active in being a part of this business, launching plans to develop business in Europe by opening a new office in the UK. The company, which has already made similar moves into the North American market, is believed to be tracking corporate customers with bases in Europe and China.
China Telecom was granted an operating licence in the US two years ago, enabling
It was quite informative and interesting. I do not think that you will be willing to provide such an information services free of charge for a long time. Best regards,
Bill Brock, For BP America Production
Thanks for a great and even though the business is “way where the music plays”, wherever that may there is always a at the end of the cable. Mike Wiseman, Esq.
Good work on the edition. Thank you for your and the short cut Submarine Telecoms I briefly visited website and found information to be interesting.
Dr. William J. Barattino, Global Broadband Solutions, LLC It was quite informative and interesting. I do not think that you will be willing to provide such an information services free of charge for a long time. Best regards, Sumio Yamano, Sumitomo Ocean Development & Engineering Co. Ltd.
traffic directly has enabled business while international operating becoming more and evaluate the on the three general terms we of very high relatively RTD Europe the less tolerant rapidly and RTD route to premium, assuming proves to be premium price the high quality sixteenth centuries routes” and West. In the to find the Europe and course. Like the or East. We
absolute right fit for
A synopsis of current news items from NewsNow, the weekly news feed available on the Submarine Telecoms Forum website.
3U Technologies Supports Development of Schilling Ultra heavy-Duty Hydraulic ROV
3U Technologies recently announced today they have completed a long-term support contract to assist the Schilling Sub-Atlantic Alliance with development of Schilling Robotics’ UHD™, an Ultra Heavy-Duty, hydraulic remotely operated vehicle (ROV).
www.subtelforum.com/NewsNow/2_july_2006.htm
Alcatel Wins Morocco-France Cable Contract
Alcatel has announced that it has signed a contract with Maroc Telecom, the leading telecommunication operator in Morocco, for a submarine cable network linking Morocco and France. Based on Alcatel’s market-leading optical solutions, the project, named Atlas Offshore and valued at Euro 26 million, will help Maroc Telecom to enhance its network capacity in support of new broadband service delivery and particularly call centers and off shoring activities.
Alcatel has announced that it has signed, in consortium with Elettra, a Telecom Italia Group company, a contract with Italy’s public scientific institution Istituto Nazionale di Fisica Nucleare (INFN) for a 5 million Euro project to deploy a submarine cable network for the research activities carried out via the NEutrino Mediterranean Observatory (NEMO) telescope.
www.subtelforum.com/NewsNow/2_july_2006.htm
ARCOS Upgrade Completed
New World Network, the principal owner of the Americas Region Caribbean Optical-ring System (ARCOS), has announced it has completed a $2 million expansion of its core Internet Protocol (IP) network with financial backing from Columbus Communications Inc.
www.subtelforum.com/NewsNow/11_june_2006.htm
Bangladesh Inaugurates First Submarine Cable
An inaugural ceremony for SEA-ME-WE-4, the first submarine cable system to land in Bangladesh, was held on 21 May 2006 at submarine cable landing station at Jhilongja, Cox’s Bazaar. Bangladesh Telegraph & Telephone Board (BTTB), the incumbent carrier for Bangladesh and the country’s representative on the SEA-ME-WE-4 consortium, released a lengthy statement about SEA-ME-WE-4 and what it will bring to Bangladesh
www.subtelforum.com/NewsNow/4_june_2006.htm
China Netcom to Sell Asia Netcom
Asia Netcom has released more details following its recent announcement that its parent company, China Netcom Group Corporation, has signed an agreement to sell all of its Asia Netcom assets to an Investor Group led by Ashmore Emerging Markets Liquid Investment Portfolio and also including Spinnaker Global Opportunity Fund Limited and Clearwater Capital Partners.
www.subtelforum.com/NewsNow/11_june_2006.htm
Consortium to Build Transpacific Cable
Telekom Malaysia Berhad (TM) has announced that it has joined a consortium of major international telecommunications entities to plan and develop a proposal for building an international undersea cable system linking South East Asia with the United States of America (USA).
The Government Ministers responsible for ICT from eastern and southern Africa unanimously approved the NEPAD ICT Broadband Network, including the East Africa Submarine System Project (EASSy) operational principles.
www.subtelforum.com/NewsNow/18_june_2006.htm
E-Marine to Be Part of New Etisalat Services Entity
Emirates Telecommunications Corporation (Etisalat) has announced a series of senior management moves, operational consolidations and the introduction of new departments as part of a restructuring program introduced last month.
www.subtelforum.com/NewsNow/4_june_2006.htm
Etisalat Executive Gives Keynote at Conference
Etisalat’s keynote speaker highlighted key challenges in developing submarine infrastructure during Submarine Networks 2006, held in Dubai on June 26-27.
www.subtelforum.com/NewsNow/2_july_2006.htm
Cutting
Global Marine Appoints of General Manager in Singapore
Global Marine Systems Limited has appointed John Walters as General Manager for its Singapore office.
www.subtelforum.com/NewsNow/4_june_2006.htm
IT International Telecom Completes Power Grid Installation
IT International Telecom, a leader in submarine cable installations, is pleased to announce the completion of the installation of eleven (11) submarine power cables in Northwestern British Columbia, Canada.
www.subtelforum.com/NewsNow/4_june_2006.htm
Hibernia Atlantic Renews Guardian Maintenance Agreement with Global Marine
Hibernia Atlantic has renewed its Guardian Private Cable Maintenance agreement with Global Marine Systems Limited.
www.subtelforum.com/NewsNow/4_june_2006.htm
Looking Beyond 2007, Workshop on the Future of SAT3
A group of organizations involved in developing telecommunications resources in Africa plan to hold a a workshop in Johannesburg, South Africa, which will discuss the future of SAT-3, a crucial submarine cable on which hinges Africa’s chances to get a smoother ride to cyberspace.
www.subtelforum.com/NewsNow/9_july_2006.htm
IT
Completes Cable for GCI
IT International Telecom Inc. has announced the completion of the North Douglas to Lena Point fiber cable project.
www.subtelforum.com/NewsNow/4_june_2006.htm
NEC Announces Maldives Contract Win
NEC Corporation has formally announced that it has signed a contract valued at US$22.7million with Dhiraagu (Dhivehi Raajjeyge Gulhun Private Limited), the largest telecom carrier in the Maldives, and Sri Lanka Telecom for an optical submarine cable system.
Nexans to Supply Inter-Island Cable Project in Norway
Bredbånd Finnmark AS has awarded Nexans a contract to supply fiber-optic cables for the first phase in the development of a fiber-optic telecommunications network throughout Finnmark, the northernmost county in Norway.
www.subtelforum.com/NewsNow/2_july_2006.htm
Pakistan Internet Uninterrupted Despite Cable Fault
Pakistan Telecommunications Company Limited (PTCL) announced that SEA-ME-WE-4 developed a shunt fault approximately 18 kilometers from Karachi Cable Station after which the customers routed immediately via SEA-ME-WE-3 without any interruption.
www.subtelforum.com/NewsNow/9_july_2006.htm
WFN Strategies Adds Ray Chrisner as Quality Manager
WFN Strategies, a provider of telecoms engineering services for terrestrial and submarine systems, recently announced the addition to its team of Ray Chrisner as Quality Manager.
www.subtelforum.com/NewsNow/9_july_2006.htm
Cutting
Telecom Italia Upgrades Cableship Teliri With Makai’s
Latest Submarine Cable Lay And Control Software
Elettra TLC, a subsidiary of Telecom Italia, has equipped their Cableship Teliri with the latest release of Makai’s suite of submarine cable planning and installation software.
www.subtelforum.com/NewsNow/2_july_2006.htm
TransTelecom to Connect Sakhalin with Russian Mainland
Russian carrier TransTelecom Company (TTC) says it has begun implementing a major project – the construction of a submarine fiber-optic cable that will connect Sakhalin Island with the company’s mainland backbone digital network.
www.subtelforum.com/NewsNow/18_june_2006.htm
Tyco to Charter Tyco Decisive to Canyon Offshore
Tyco Telecommunications has announced that it has chartered the Tyco Decisive to Houston-based Canyon Offshore for four months beginning June 1, 2006.
www.subtelforum.com/NewsNow/4_june_2006.htm
Tyco Completes TWA-1
Tyco Telecommunications (US) Inc. has announced that it has achieved the status of Ready for Provisional Acceptance (RFPA) under the terms of a multi-million dollar turnkey contract with Transworld Associates (Pvt.) Ltd, for the TWA-1 Undersea Cable Network.
www.subtelforum.com/NewsNow/2_july_2006.htm
Tyco Wins Sakhalin Island
Contract
Tyco Telecommunications has announced it has been selected by TransTelecom Company (TTC), a leading Russian backbone operator, as the sole provider of the first undersea communications system connecting the Sakhalin Islands to TTC’s digital mainland backbone.
www.subtelforum.com/NewsNow/2_july_2006.htm
Yipes Completes Carrier Network Integration with Global Partners
Yipes Enterprise Services, Inc., the leading global provider of managed, end-to-end Ethernet solutions for enterprise customers, today announced it has completed the integration of key international carrier partners, expanding the capabilities of its Global Area Network (GAN) services in major business hubs across Europe, the Pacific Rim and Latin America.
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Tel: + 47 22 88 61 00
Fax: + 47 22 88 61 01
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Fax: +1 281 578 6991
E-mail: les.valentine@nexans.com
Cable Technology Snapshot
By
Gabriel Ruhan
With new communication services entering the mainstream such as Voice over Internet Protocol (VoIP) and IPTV it is important to remember that the vast majority of all international communications traffic still passes through a subsea network.
It is more than 150 years since Global Marine laid the first international submarine telegraph cable linking Britain to France but, despite major developments in satellite communications, subsea networks still provide a more cost effective and reliable solution which has the capacity to handle mass global communications on a real-time basis.
This growing demand for new communication services, combined with the continued appetite for business support services, such as outsourced call centres and back-up data centres is positive news for the subsea industry. Recent findings from TeleGeography Research, who monitor global bandwidth usage, showed that the telecoms industry raised capacity by about one terabit (a trillion bits) per second to about 5.5 terabits per second last year just to meet the growing demand across the Atlantic.
Additionally, more liberal telecom regulation in regions such as the Caribbean is creating more competitive telecom markets. This is driving demand from local operators for regional network installations that will provide
domestic consumers and businesses with the infrastructure for cheaper and more reliable telephone calls and internet services.
However, despite all these positive signs, Global Marine does not anticipate the next wave of big cable installations to happen until between 2010 to 2020 and, when they do, this will be a gradual and structured upgrade of trans-oceanic systems whose older cables will be coming to the end of the 25 year life span.
In technology terms, this means that the industry is currently focusing mainly on cable maintenance, rather than installation, although it is also important to highlight that we should not view our expertise as being purely of relevance for the telecoms sector.
As a case in point, Global Marine has been able to utilise its cabling knowledge and capabilities to further build its presence in the oil and gas, renewable energy, defence and scientific research sectors.
Recent examples of our work include providing power and fibre optic links to Canada’s most advanced seafloor observatory in conjunction with the University of Victoria (VENUS) and repairing a Tsunami monitoring system for the Japan Agency for Marine-Earth Science and Technology (JAMSTEC).
But what are the consequences of this growing demand for telecom based services? One is
that, compared to 150 years ago, the world’s seafloors are increasingly populated with subsea cable. This is particularly true in areas such as in the Atlantic and the South East Asia region.
Cable planning and maintenance is therefore a major issue for market participants and requires intricate knowledge of not only where cables lay, but also the characteristics of particular areas of seafloor.
To avoid “driving blind”, the industry relies upon complex GIS (Global Information Systems) such as Global Marine’s GeoCable which comprises over 1.9 million kilometres of cable route data and 3000 hydrographic charts to provide extensive cable and oceanographic information to allow customers to efficiently plan and execute cable installation and maintenance
After the planning stage, cable laying software is then crucial for the operational part of installation projects and Global Marine has a proprietary PC-based application, Cable Lay Planner, which applies an industry standard cable laying methodology to a variety of cable configurations.
This ensures the correct amount of cable slack is introduced during the laying process, which means that a subsea network will not be vulnerable to snagging from fishing lines or fatigue from strong currents – during the laying
process, the software can also automatically feed data back to ship board cable slack control devices.
How is this process completed? By remote operated vehicles (ROVs) which are an essential tool in both cable laying and maintenance projects. Cables laid under 1,500metres of water must be buried to protect them from potential damage from sea trawlers. More generally, the type of ROV used within the industry will depend upon the type of project, depth of water, type of seafloor and the weight of fibre optic cable.
Cable laying requires ROVs equipped with tools such as jettlegs and ploughs which create the furrows into which cables are laid and then buried. Conversely, maintenance work makes use of grapnels and cutters to lift what can be heavy cables from the seabed floor and then cut them for new fully working pieces to be rejoined to the existing cable.
Global Marine has approximately 20 ROVs to cover any subsea cable scenario and employs highly experienced ROV operatives aboard its ships to ensure each project is completed to the highest possible standards.
In conclusion, these are exciting times for the subsea industry as the growing demand for new communications services from both traditional and newer regions is helping stimulate demand for subsea engineering technologies and expertise.
Whilst use of the word “recovery” is still premature, Global Marine continues to see further market opportunities in both the installation and maintenance markets, which is further underpinned by our work in related industries such as the oil and gas sector, where our technology continues to be highly successful.
Gabriel Ruhan is Managing Director of Global Marine and is dedicated to delivering the company’s business plan. He has extensive business experience and, prior to joining Global Marine Systems in 2004, spent three years consolidating the USbased IT hosting and outsourcing business, NaviSite. Gabriel is adept at handling the challenges of realigning corporate strategy whilst maintaining tactical momentum and puts this into effect in each of the sectors Global Marine operates in.
How Are Submarine Cable Networks Of The Future Likely To Be Financed?
Andrew D. Lipman and Ulises R. Pin
Constructing, maintaining and upgrading submarine cable networks requires significant amounts of capital. Are the sources of financing in 2006 different than those available in the past? Is there a role for venture capital, private equity or other sources of financing? The answer appears to depend mainly on the actual demand for capacity and the location of any potential new system. However, the ability to obtain funding for a new system not only lies on a strategically-located project, but largely depends on the sponsors’ ability to accommodate the requirements generally imposed by prospective investors and lenders.
There are two large groups of submarine cable networks. The first group is formed by carrier-financed and operated submarine cable networks. Traditionally these systems function as “carrier clubs” where incumbent telecommunications providers of one or more countries join forces to build and operate the network. Typically, one carrier leads the group and is responsible for the overall administration of the network. Other carriers join the consortium and act as landing parties for the cable in their respective jurisdictions. Funds for construction
and operation of the networks are usually provided by the carriers and generally there is no need for outside sources of financing. Capacity on the network is allocated in proportion to each carrier’s participation in the consortium and is used by the carriers to transmit their own voice and data traffic.
The second large group of submarine cables is comprised of “private” or non-carrier sponsored networks. These systems peaked in the late nineties, when a number of companies ventured into connecting the world. The business model is fairly straightforward, a private sponsor leads the construction of a network and raises funding from capital markets and/or commercial banks with the goal of providing bulk capacity to competitive telecommunications providers and large corporate users. Developers act as “carriers’ carriers” because they generally do not have their own traffic to transport, but aim at filling the requirements of others by leasing circuits or entering into sales of capacity mainly in the form of Indefeasible Rights of Use (“IRUs”).
During the telecommunications industry downturn in the early part of this decade, many of the carrier-sponsored cables remained relatively untouched, although there were very few announced new cables or expansions of existing cables. However, many of the private submarine cable network developers experienced financial difficulties, including several large companies that went bankrupt or were forced to refinance their networks. Many assets ended up in the hands of creditors that hoped to recoup their investments by selling collateral. Subsequently, the majority of these assets have been sold. Many of them were purchased at a few cents on the dollar of their original cost.
For years it was perceived that there was just too much unused capacity available and there was no need for any new cables in the future. Moreover, it was unclear whether the telecommunications industry would ever be able to attract new capital. However, the worst years for the telecommunications industry appear to be over and the so-called “bandwidth glut” is slowly coming to an end, as increasing international bandwidth demand has depleted inventories of unsold circuits on many submarine networks. According to Telegeography, several network operators have lit additional wavelengths and fiber pairs on several routes as lit bandwidth supply and bandwidth demand are coming into balance. While this does not mean that there will be a multitude of independent new developers parading
1 The Bandwidth Glut is Over, in Telegeography (April 3, 2006).
business plans throughout Wall Street or other financial markets as we saw in the late nineties, it certainly means that there are opportunities available for new investment in certain well positioned assets or projects.
IP-enabled communications and other bandwidth intensive applications such as IPTV, have the potential to further drive the demand for undersea cables and there will be demand for additional capacity. There is still significant unused capacity available in numerous fiber routes including the US-Europe and US-Far East routes where multiple carrier-owned and private systems interconnect these continents. However, certain regions, such as the Middle East, South Asia and Africa face capacity constraints and, according to several market studies, would require new systems to cope with consumer demand for broadband. Thus, there are opportunities out there waiting to be taken to the next level.
So how are the networks of the future likely to be financed? The role for carriersponsored, self-financed cables appears to be a somewhat proven method and will likely continue for the foreseeable future. For example, Telekom Malaysia recently announced it is leading a consortium of seven Asian telecommunications carriers to build a new high capacity system linking Southeast Asia with the United States. But is there any role for new privately-sponsored cables? The answer appears to be affirmative.
In the past couple of years, private equity funds, venture capitalists and other institutional investors have largely returned to the telecommunications industry and have made significant investments in traditional and not-so traditional telecom ventures, such as the acquisition of satellite providers like Intelsat. Private network developers can capitalize on the opportunities available in certain areas where capacity is scarce. However, business plans for the second half of this decade will necessarily need to be more regional in scope, rather than the “interconnect the world” type approach of the past.
A well-tailored regional business plan could very well be fundable. Depending on whether the project is in its early stages or in more advanced stages of development, the answer to the financing may be in either venture capital or private equity. For new networks, the answer may lie on venture capital. Typically, venture funds look at a number of elements to determine whether to make an investment. First, the financial model must support a substantial return on the equity investment (venture funds expect returns of 30% and more). Finding an underserved region or identifying capacity demands is only the first step in crafting a successful business plan. The sponsors must also ensure that the project supports the required rates of return on equity capital that investors are seeking.
Second, in virtually all circumstances, the business plan must demonstrate that the network will be “fully funded,” that is that the equity financing will be sufficient for the company to reach positive cash flow. This means that the more pre-sales or capacity commitments that the sponsors can obtain at the outset, the easier the chances to secure financing.
Large investments like those required for a new privately-sponsored submarine cable network will, in virtually all cases, require a debt component in addition to the equity provided by the sponsors and their backers. Although commercial banks were some of the most affected by the bankruptcies and restructurings of the past, it is hard to conceive that they will not provide financing to a well-planned venture, backed by well-known funds. Moreover, in some cases, some of the underserved regions or countries may also qualify for assistance or lower interest loans from export agencies or other regional development banks. However, the requirements imposed by banks and development agencies may appear to be incompatible with the initial requirements of the equity financers. Structuring the debt piece of the overall financing would generally be accomplished simultaneously with the equity. The business plan should be able to balance the requirements imposed by the equity and the banks, including allowing for prompt repayment of the debt and ensuring that the debtto-equity ratios and other financial covenants generally imposed by lenders will be met.
Another key aspect is corporate governance. Although the track record of the sponsors and their knowledge of the industry and/ or the region are fundamental, investors would typically insist on significant levels of control of the company through either control of the board or by means of significant negative blocking rights. In our experience, these are some of the most discussed and negotiated issues in structuring a transaction. However, flexibility by the sponsors and ability to work together on these matters would generally facilitate completing the financing process and bring the project to fruition. After the deal is closed, having a shared vision between the sponsors and the venture capitalists generally facilitates the ongoing operations of the network.
Finally, and almost most importantly, there should be a clear exit strategy for the investors. Although an initial public offering may have been the expected exit strategy prior to the telecom bubble, this avenue may not be as easily available a few years from now. Thus, in developing an attractive business plan, sponsors need to clearly identify potential alternatives to an IPO, including narrowing down potential buyers for the network or other prospects for consolidation.
Thus, there appear to be several regional opportunities out there that may bring traditional and non-traditional investors back to the industry. Crafting the appropriate business plan and the ability to balance the business and legal requirements of the debt and equity financiers is largely what separates a funded project from one that is simply a good idea.
Andrew D. Lipman
Andrew Lipman has spent more than 25 years developing the firm’s Telecommunications, Media and Technology Group into one of the largest practices of its kind in the nation. He practices in virtually every aspect of communications law and related fields, including regulatory, transactional, litigation, legislative and land use. The TMT Group is international in scope, representing clients in the U.S., Central and South America, Europe, Asia and other parts of the world.
Ulises R. Pin
Ulises Pin represents domestic and international telecommunications companies before the Federal Communications Commission as well as telecommunications regulators in Mexico, Latin America, Europe and Asia. He advises clients on wireline, wireless and international communications, value-added services, VoIP, infrastructure projects (land and submarine networks), satellite services and emerging technologies.
SubmarineTelecoms
Submarine Telecoms Forum is seeking like-minded sponsors to contribute their corporate images to the 2007 Submarine Cable Industry Calendar.
The 2007 Submarine Cable Industry calendar will be provided free of charge to Submarine Telecoms Forum’s subscriber list, encompassing some 5000+ readers from 85 countries, including senior government and international organization officials, telecom company executives and team, support and supply company management, and technical, sales and
purchasing staff, field and shipboard personnel, academicians, consultants, financiers, and legal specialists.
The Submarine Telecoms Forum industry calendar will be printed in full colour on high quality 200gsm silk art paper, approx 600 x 300mm, giving sponsors an area of approx 300 x 300mm to display their corporate image.
Sponsorship Cost: $7,000 per monthly membership.
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Upgrades: Theory and Practice
By Igor Czajkowski
For undersea systems operating at only a small fraction of their intended capacity, upgrades are an obvious solution to capacity demand growth. At the same time, operators are increasingly recognising the benefits of a multiple-supplier environment on their cables as they seek the best technical and commercial upgrade solutions for their networks. So what does an upgrade involve, and are there any particular considerations for upgrading with a vendor other than the original supplier?
Why upgrade?
Upgrades represent only one of several available routes to new capacity, alongside leasing capacity on another cable or investing in a new cable altogether. Needless to say, there is usually a different “right answer” in each case.
Leasing capacity has become more attractive recently, due to declining prices and the availability of short term deals. It is by its very nature an enduring cost compared with the one-off cost of an upgrade, but has particular advantages
for small capacities or short durations, New build gives access to enormous capacities, but represents a large capital investment and a significant implementation time. Whilst perhaps ultimately inevitable, there can be significant benefits from delaying the corresponding large capital expenditure for as long as possible, with the added benefits of advances in technology in the interim.
In theory…
Firstly, not all cables can be upgraded, being limited to optically amplified systems rather than those with regenerators. Consequently on some routes upgrades do not present a viable option. Although one might consider changing the submerged plant, this would be very expensive, time-consuming and disruptive to traffic compared with upgrades involving only the terminal transmission equipment, which are relatively quick and inexpensive.
impact on existing traffic. In the absence of one being available, there is always the related possibility of a complete terminal replacement, with the added major consideration of what to do with the existing traffic. An alternative traffic path must be found for the periods covering commissioning and acceptance testing.
An alternative approach is the overlay of new equipment which adds new wavelengths (usually via a coupler), keeping the original equipment and traffic untouched. This is generally possible, and the advantages of an overlay are clear, although it offers less capacity than a full replacement, being limited by the existing wavelength implementation.
In many cases upgrades can add capacity significantly beyond their original design, exploiting technology advances. This can have particular benefits for single-channel (2.5 or 5 Gbit/s) and WDM 2.5 Gbit/s cables which can generally be upgraded to multiples of their original design capacity using 10 Gbit/s channels typically at half the spacing of the earlier systems. It is usually possible to accommodate several such new channels within the amplifier bandwidth of a single-channel cable. For a WDM cable, the combination of the improvement in bit-rate (x4) and channel spacing (x2) suggests an upgrade with x8 improvement over original design capacity.
The most straightforward way to add new terminal equipment is to light a “dark-fibre”, and has no
Squeezing the required number of new channels into the repeater bandwidth is only half the story.
Each repeater in the chain has a limited output power, and adding new channels means less power per channel (both for existing and newer channels). This means that extra channels can be added only if the current channels operate with some margin. Fortunately, this is usually the case, as most installed systems have lower transmission impairments (accumulated repeater noise, non-linear effects, chromatic dispersion and polarisation effects to name a few) and better manufacturing tolerances than allowed for in their design. Of course, new terminal equipment also benefits from advanced Forward Error Correction (FEC), improved receive-filter design, and newer transmission formats, further increasing the margin available to new channels.
The actual available margin will depend on many specific characteristics of an individual cable, but each extra 3dB allows for a doubling of capacity. In some instances, 6 dB to 9dB are available, enabling the 8 fold increase in capacity given in the earlier example.
Newer 10 Gbit/s DWDM cables typically already benefit from more recent FEC and closer channel spacing, but might still achieve some marginal capacity improvements and will also benefit from lower cost, more compact and up-to-date equipment.
… and in practice
The key to a successful upgrade is preparation, preparation – and more preparation! This includes gathering as much information as possible (dispersion map, fibre types, repeater parameters, repair history, etc), and checking station details thoroughly. If recent data are not available, measurements can be made that don’t affect existing traffic. This includes measuring optical spectra (confirming the wavelengths and received signal to noise) and examining the FEC correction rate records (which gives margin – ideally checking over long periods to determine fluctuations).
Performing precise computer simulations is also vital to planning a successful upgrade. With good inputs, such simulations can give accurate predictions, but can be time-consuming and require skill. Typically simulations are repeated several times, varying key parameters to determine the best technical solution. For these reasons the experience of the individuals performing the simulation is as important as the software itself. Finally, the upgrade should be planned allowing a roll-back at each stage should any problems be encountered.
Multi-vendor considerations
There have been a number of recent upgrades by vendors other than those who originally supplied the system. The benefits of this approach are clear, and include access to technology choice and competitive supply assuring the best price.
Establishing a multi-vendor environment on a cable system need not be difficult, but does present a few technical and commercial considerations.
Inserting a coupler into the system for an overlay of second-vendor equipment is a simple operation that can typically be completed in less than fifteen minutes. Insertion is usually between the line amplifier of the existing terminal and the cable.
Disruption to existing traffic can be kept to a minimum by temporarily switching to protection capacity where available, and adding the couplers to the segments in a sequentially staged manner. The couplers themselves add some loss, but the section to the first undersea repeater is usually short compared with the spacing between repeaters, and often there are attenuators which can be removed. The penalty introduced by the couplers is effectively spread across the entire line, decreasing with the total number of repeaters. For example, two 3dB couplers will add less than 0.3 dB of penalty to a line with 50 repeaters. It is also worth noting that some systems already have suitable couplers in place, avoiding the need to insert new ones. Otherwise, the coupler loss may be reduced if this is necessary.
Another consideration for overlay is that stable wavelength and power control is essential to avoid any direct interference between adjacent channels, but this is normal for any WDM equipment and all respectable suppliers maintain tight control of these parameters.
The original submerged plant monitoring equipment can in many cases be retained after upgrade, as this often operates independently of the data transmission functions. When it does not, then as more channels are added, it will be necessary to adjust modulation levels or to ensure that modulation is also applied to the new channels.
The new upgrade equipment operates independently of the existing equipment, so can be separately managed, but it can be useful if alarm and other data are made available to higher-level management systems where necessary.
Quite apart from overcoming the technical challenges, what about the warranty of the system being upgraded? These typically last 5 years, so for many upgrades they have already expired, but a secondary concern will be for continued support from the original supplier. Here, commercial considerations dictate that the original supplier needs to remain “reasonable” in order to be considered for future supply contracts with both the customer concerned and other customers.
Looking to the future
Upgrades are well suited to today’s economic and technical climate, and can be a relatively pain-free route to rapid and cost-effective capacity increase, but require careful preparation and attention to detail.
We can expect technological advances to offer further increases in achievable capacity (from better FEC and new transmission formats) and to offer new interfaces (such as 10 Gigabit Ethernet). More speculatively we may see new architectures, such as Add-Drop terminals allowing economic bypass of intermediate stations with low traffic needs, and new features allowing rapid or even self-provisioning incremental upgrades.
Increasingly, carriers upgrading their cables are seeking to take advantages not only of these ongoing advances in technology, but also of a competitive supplier market that enables them to remove their dependence on a single supplier for upgrading a cable. A few carefully selected requirements on new build systems, such as the inclusion of in-line couplers for future hit-less upgrades, will ease this transition further.
Igor Czajkowski is Manager, Product Marketing at Azea Networks. He has nearly 20 years of experience in Telecoms, having previously worked with Nortel Networks in access products, metro optical networks and optical component design. He holds a Ph.D in optoelectronic physics from Surrey University.
Ultra-Low-Loss Fibers Enable Advanced Performance in Submarine Applications
By Dr. Merrion Edwards and Rita Rukosueva
The submarine market space consists of two main segments: repeatered and unrepeatered networks. Repeatered networks require in-line amplification and can be anything from regional networks of up to 3,000 km, or intra-continental networks of up to 6,500 km, to trans-oceanic networks which can extend to 3,000 km.
In contrast, unrepeatered submarine systems are short-haul undersea networks designed for distances of up to around 400 km that are achieved without in-line amplification.
This range in network types and lengths means that submarine networks have a variety of reach and capacity needs, and as a consequence have diverse requirements in terms of telecommunications systems and optical fiber solutions. Common to all networks however, is the need to minimize the signal loss due to fiber attenuation. Lowering the fiber attenuation yields cost efficiencies, and as a consequence ultralow-loss fibers bring significant benefits to all submarine networks.
Submarine Network Design Needs a Diverse Fiber Portfolio
Repeatered submarine networks use amplification to overcome fiber attenuation as so low-loss fibers can enable significant savings in amplification costs. However, repeatered networks are also limited by the accumulation of chromatic dispersion over the transmission path that degrades the signal. For such networks, effective management of and compensation for dispersion
is another critical element. Since, these networks vary greatly in number of channels (up to 96) and in length (from about 400 km to 3,000 km) several fiber types were developed and are being used to achieve those capacities per fiber and transmission distances in the most cost-efficient way.
For regional systems up to 3,000 km a standard negative dispersion submarine fiber with a low positive dispersion slope (-D, S>0) such as Corning® Vascade® LS+ fiber, is used in the transmission span, or if more power handling capability is required a large effective area, negative dispersion (-D, S>0) submarine fiber like Corning® Vascade® LEAF® fiber is deployed, as shown in Figure . For inter-continental systems that extend beyond 3000 km and up to 6500 km, the system often needs to cope with higher transmission powers but also needs a low dispersion slope and so a hybrid combination of a high power handling negative dispersion large effective area submarine grade fiber (like Corning Vascade LEAF) and a standard negative dispersion fiber (like Corning Vascade LS+) with a low dispersion slope is often used within each transmission span. Dispersion compensation is achieved in regional and inter-continental networks by inserting a span (or part of a span) of positive dispersion fiber, such as standard singlemode fiber or a low-loss fiber.
Ultra long-haul systems are over 6,500 km, and in these systems, the dispersion slope of the fiber becomes a problem as it results in different
Growth in Unrepeatered Market
Dispersion Managed Fiber
Vascade® R1000
Link Length > 3000km?
Link Length > 6500km? No Yes No
fiber can be viewed as the main limiting factor in determining the maximum span length. Many technologies such as Forward Error Correction (FEC), Raman amplification, and Remote Optically Pumped Amplifiers (ROPA) are used to extend the span length.
Standard negative dispersion fiber (moderate or large Aeff)
Vascade® LS+ or Vascade® LEAF
Vascade® LS+ and Vascade® LEAF Channel Count > 80?
Hybrid: large & moderate Aeff negative dispersion fiber
As a consequence every submarine project, depending on system design, will require slightly different optical fiber attributes in order to maximize performance and minimize attenuation and dispersion.
Looking at the re-emerging submarine market, of particular interest is the strong growth in cable demand and deployment in both the regional and unrepeatered market segments. The Caribbean has six new intra-regional networks underway, there is also significant regional network planning and build activity in Southeast Asia, in the Pacific Islands, and in the Middle East and the Mediterranean Basin. There are currently on the order of sixty four potential new unrepeatered projects being discussed around the world. The hot spots of unrepeatered network activity include Europe where twenty projects are proposed, Asia where there are ten projects, Africa where there are eight potential projects and the Caribbean that has six new projects as shown in Figure 2.
transmission channels accumulating different amounts of dispersion. For ultra long-haul networks dispersion managed systems provide a solution where a positive dispersion fiber with a positive slope and a large effective area and a complementary negative dispersion fiber with a negative slope are deployed within each span of the transmission line to compensate for both dispersion and dispersion slope, and to also provide high power handling capability.
Unrepeatered systems need to span the farthest distance possible without any form of amplification and the attenuation of the optical
Therefore, submarine system designers require access to a diverse portfolio of submarine grade fiber types that are inter-compatible in order to optimize both repeatered and unrepeatered system design as well as for overall cost optimization.
Figure 2: There are 64 known potential unrepeatered projects across the globe today.
In terrestrial/continental networks, the growth in the internet and associated growth in ecommerce and global data connectivity is driving the “broadband movement” that is resulting in upgrades to the access network and associated upgrades to metro, regional and backbone networks. For insular nations and those nations separated by sea, the equivalent networks are often inherently submarine, and the broadband movement, for those nations, is driving the installation of new submarine cable. As the broadband movement spreads globally, the associated ever increasing growth in consumer bandwidth demand will underpin the continuation of a strong regional and unrepeatered submarine cable market. As unrepeatered systems rely heavily on the availability of ultra-low-loss fiber to enable long span lengths, and the deployment of ultra-low-loss fiber in repeatered systems enables amplification cost savings, the need for ultra-lowloss fiber in the submarine market is augmenting.
Corning introduces Vascade® EX1000
To support the need for low-loss fiber in both the unrepeatered and repeatered markets, Corning has developed and introduced a new ultra-lowloss submarine fiber, Vascade® EX000 fiber. Benefiting from Corning’s unsurpassed fiber manufacturing expertise and capability, Vascade® EX000 fiber is a silica core fiber that features ultra low-loss and offers significant performance advantages for unrepeatered networks.
Transmission tests were recently conducted at Corning’s research laboratories comparing the unrepeatered performance of Vascade® EX000 fiber to a premium grade standard single-mode
fiber with a very low average attenuation of 0.19 dB/km. The relative performance of the fibers with non return to zero (NRZ) modulation and a more sophisticated Differential Phase Shift Keying (DPSK) modulation format were also compared. Using a basic transmission system with eight channels at 10 Gb/s, it was demonstrated that Vascade® EX1000 fiber provides up to 14% more reach over this a low loss premium grade standard single-mode fiber when using basic EDFAs and NRZ modulation, and also when using Raman assisted EDFA amplification and/or DPSK modulation (see Figure 3). As previously demonstratedi, ultra-low-loss fibers like Vascade EX1000 fiber can facilitate an even greater (on the order of 7%) reach advantage over a normal grade standard single-mode fiber.
The cost of a repeatered network will greatly exceed the cost of an equivalent unrepeatered network, as repeatered networks require inline amplifiers. Hence, a network that it just a few kilometers over the ultimate reach of unrepeatered system can cost 60 to 00% more to install. Ultra-lowloss fibers like Vascade® EX1000 fiber enables an extension of the reach of
unrepeatered systems so that more networks can benefit from the cost advantages of unamplified sub-sea networks. In addition, ultra-low-loss fibers provide cost and performance benefits for repeatered systems, offering extended span lengths and low loss dispersion compensation solutions.
Conclusion
Every submarine network, depending on system design, requires a different combination of optical fiber solutions. To meet the needs of leading edge submarine network design, fiber suppliers must provide a full portfolio of inter-compatible optical fibers. With the introduction of its new ultra-low-loss fiber, Vascade® EX000, Corning’s portfolio of submarine fiber products now consists of five inter-compatible fibers, making Corning
Transmission System
EDFA + Raman +DPSK
EDFA + Raman + NRZ
EDFA + DPSK
EDFA + NRZ
Vascade® EX1000
Standard single-mode
Normalized System Reach
Figure 3 Corning® Vascade® EX1000 fiber enables up to 14% more reach than a premium grade standard single-mode fiber with an average attenuation of 0.19 dB/km.
1 Normal grade standard single-mode fiber has an attenuation of 0.2 dB/km
the supplier with the largest and most complete portfolio of submarine fibers; a portfolio that enables advanced submarine network solutions for all submarine network segments.
References
i. “The Long and the Short of Regional Submarine Networks”, Stringer, J : WE B1.3, SupOptic 2004.
PTC’07: Beyond Telecom
The 29th Annual Telecommunications Conference & Exhibition 14-17 January 2007
Hilton Hawaiian Village Beach Resort & Spa
Manage Threats & Seize New Opportunities at PTC’07
PTC’07: Beyond Telecom will explore the critical technology, business and policy issues created by the accelerated and continued convergence of communication and entertainment services on IP. PTC’07 brings together the best minds, creating the most productive business buzz and provocative dialogue for social change in the global ICT community.
Topics include: Disaster management • Distance learning Health care • VoIP • Video, youth, and lifestyle marketing Cyber communities & gaming • Net neutrality & IPTV Next generation service licensing • Satellite • Submarine Cable
Discover more business opportunities in the NEW dynamic MidPacific Marketplace - featuring exhibits, private meeting rooms, Planet PTC Cyber café, and social functions.
Mark your calendar now to attend PTC’07! For program, registration, exhibits and sponsorship information, visit www.ptc07. org, call +1.808.941.3789 or email: ptc07@ptc.org. Don’t miss out on this premier telecoms events!
Rita Rukosueva is currently the Submarine Products Manager for Corning Incorporated. She has been with the corporation for over 7 years. Prior to her current position, Rukosueva was the Market Development Engineering Manager where she made numerous contributions in the development of next generation optical fiber products. Rukosueva holds a M. S. degree in Physics from Moscow State University in Russia.
Dr. Merrion Edwards is currently the Manager, Premium Products for Corning Incorporated. She has over 16 years of experience in the field of telecommunications. She has spent the last 7 years as Market Development and System Engineering Manager for Corning Optical Fiber and has expertise in broad range of telecommunication applications including long-haul, metro, premises and submarine. Prior to joining Corning, Edwards conducted research into photonic devices for telecommunications and sensing with BICC Cables, Ltd. in the United Kingdom. Edwards holds a PhD in Optoelectronics from Southampton University. She lives in with her husband Henry and three children in North Wales in the United Kingdom.
The E arl y Pass ive Bra nc hi ng Un it
Branching Units Get Smart
By Ray Chrisner
For a s m all region al s y s tem c o mpris ed of 3 c able end- points (c able s ta tio ns or c om mun ic ati ons plat for ms ), in the abs enc e o f a Branc hin g Un it , s ta tion- t o-s tati on c o nnec t iv ity is ac h iev ed by s ingle c a ble land ings at tw o s t ati ons a nd a do uble c abl e lan ding at the one in the midd le By util iz ing a BU , a ll three s t ati ons c an be c onnec ted by s i ngle c a ble land ings a nd the qua nti ty of c able d eploy ed wil l b e min im iz ed (s ee F igure 1).
In the age of regenerative repeatered underwater systems, Branching Units (BU’s) typically were passive devices used to reduce the quantity of cable in regional systems (i.e., UNISUR). The passive nature of these BU’s did not permit any power of fiber switching. As such, when cable cuts or faults did occur, capacity re-routing or power reconfiguration was not possible.
These early generation BU’s are in stark contrast to BU’s being planned for today’s regional systems and conceptualized for the next generation of their evolution. This paper addresses the various stages of BU evolution and provides a snap-shot of what the future may hold for these devices.
The Early Passive Branching Unit
Passive BU’s were used in undersea fiberoptic systems through the evolution of the technology from regenerative repeaters into the introduction of repeaters with optical amplifiers.
Next Generation Power Switched Branching Units
The Branc h ing Uni t h as 3 s ides , on e d es igna ted as the trunk and t wo as branc hes T he mai n power pa th in Fi gure 1 is fro m S ta tion A to S ta tion B w it h PF E powering be ing pos it iv e in S tat ion
B where the PFE voltage polarity is negative (-). Powering from Station C is negative PFE polarity to a ground at the BU.
A and nega tiv e in S ta tion B. For the BU, t he s i de fac in g th e s tat ion wit h p os itiv e Power Fe ed Equi pme nt (P F E) v ol tage po lari ty (+) is c al led th e trunk . The ma in power pat h c on tinu es to St ati on B where th e PF E v ol tage polar ity is n egat iv e (-) Powering from Sta tio n C is nega tiv e PF E polari ty to a ground a t the B U.
For a small regional system comprised of 3 cable end-points (cable stations or communications platforms), in the absence of a Branching Unit, station-to-station connectivity is achieved by single cable landings at two stations and a double cable landing at the one in the middle. By utilizing a BU, all three stations can be connected by single cable landings and the quantity of cable deployed will be minimized (see Figure 1).
Prior to the introduction of multiple wavelength (WDM) transmission, purchasers of long-distance transcontinental systems wanted the flexibility to provide BU connectivity via 1 or 2 fiber pairs but be able to dynamically bypass branches with faults or bypass stations no longer wanting to be part of he system. These requirements led to the development of power switched branching units (PSBU’s).
In a two fiber pair system, PSBU’s provided connectivity as depicted in Figure 1 but also could drop both fiber pairs to the branch station (Station C) as shown in Figure 2.
With a pas s iv e BU , in the ev en t of a s hunt faul t along t he main power pa th (A- B), PF E v o lta ge is auto ma tic ally readj us ted , power to t he rep eat ers is ma i ntain ed, and tr ans m is s ion c o nti nues . In the ev ent o f a c abl e bre ak al ong the main power pa th , t rans mis s ion is los t in t he leg wit h the break , but t he other t wo s tat ions re ma in c o nnec te d. In the ev ent o f a s hun t fau lt or c a ble break in the leg th at is powered in to the grou nd a t th e BU (S ta ti on C to BU in Figure 1) , trans mis s ion is los t in tha t leg 1
The Branching Unit has 3 sides, one designated as the trunk and two as branches. The main power path in Figure 1 is from Station A to Station B with PFE powering being positive in Station A and negative in Station B. For the BU, the side facing the station with positive Power Feed Equipment (PFE) voltage polarity (+) is called the trunk. The main power path continues to Station
With a passive BU, in the event of a shunt fault along the main power path (A-B), PFE voltage is automatically readjusted, power to the repeaters is maintained, and transmission continues. In the event of a cable break along the main power path, transmission is lost in the leg with the break, but the other two stations remain connected. In the event of a shunt fault or cable break in the leg that is powered into the ground at the BU (Station C to BU in Figure 1), transmission is lost in that leg1.
Pas s iv e BU ’s are ex c elle nt dev ic es for und ers ea ap plic ations . Bec aus e of t he abs enc e of ac t iv e c ompone nts they hav e v ery l ow FI T ra tes ( fai lures i n 1 09 hours ).
Passive BU’s are excellent devices for undersea applications. Because of the absence of active components they have very low FIT rates (failures in 109 hours).
The PSBU has the advantage over passive BU’s in that if there were a transmission affecting fault between Station C and the BU, the PSBU could switch all fiber pairs as a straight through path from Station A to Station B and bypass the faulted branch leg. Once the repair was made, the PSBU could be reconfigured to restore the original connectivity of the system.
Pas s iv e BU ’s were us ed in unders e a fiberop tic s y s te m s throu gh the ev olu tio n o f the t ec hnolo gy from regen erat iv e repe aters in to the in troduc tion o f rep eaters w ith op tic al a mpl ifi ers .
The control of the PSBU was via a sequence of powering steps performed via PFE’s at Stations A, B, and C. The steps controlled a network of relays inside the BU which made the fiber
1 If th e shunt fau lt is between the BU and the f irs t rep eater to ward Station C, tr ansm iss ion m ay be main tained – in all other cases, trans mission is very lik ely to be los t.
1 If the shunt fault is between the BU and the first repeater toward Station C, transmission may be maintained – in all other cases, transmission is very likely to be lost.
Station A
C Station B
Figure 1 – Branchin g Uni t Co nnecting 3 Stations
switching possible. From a reliability perspective, the PSBU continued to have a very low FIT rate which made it attractive for undersea applications.
The P S BU has the adv an tage ov er pas s iv e BU’s in t hat if there were a trans m is s ion af fec t ing faul t b etwe en S ta tion C and the BU, the P S BU c o uld s witc h all f iber pairs as a s traig ht thr ough path fro m S ta tion A to S ta tion B a nd by p as s t he faul ted branc h leg Onc e the r epair was made , the P S BU c ould be rec onf igured t o res tore the orig inal c onnec tiv i ty o f th e s y s te m .
Branching Units in WDM Systems
This kind of design has strong applicability in regions where all branch locations are not ready for connectivity at RFPA. Several stubbed PSBU’s can be part of the original system deployment with the eventual intention of connecting those to branch locations in the future. By being power switchable, powering of the PSBU can be reconfigured to maintain connectivity among major portions of the system when faults or cable breaks occur.
The c o ntrol o f the PS BU was v ia a s equ enc e o f poweri ng s te ps per for med v ia P FE ’s a t S tat ions
to have equipment that receives and transmits the appropriate wavelength or wavelengths. For a regional system that has branch locations in separate countries or under different ownership, the politics of all wavelengths possibly being received may not make this an acceptable feature.
Transmission management/control of WDM systems and the need to minimize additional attenuation in future regional systems may motivate the next generation of PSBU’s.
The Wavelength Selectable PSBU
A, B, and C . Th e s teps c on trol led a n etwork of relay s i ns ide the B U wh ic h made the fib er s witc hing pos s ib le. Fro m a rel iabil ity pers pec t iv e, t he P S BU c on tin ued to hav e a v ery low F IT rate w hic h ma de it at trac t iv e for unders ea app lic at ions
Branc hi ng Un its in WD M S yste ms
As fiberoptic transmission evolved into providing multiple wavelength capacity, purchasers wished to selectively use single wavelengths to connect branch locations. This need is most prevalent in regional or festoon type systems.
The PSBU for WDM applications is very reliable since no active components are added to its single wavelength counterpart. Hence, it remains as a robust element for underwater application.
As fibero ptic tra ns mis s io n ev o lv ed int o prov iding mul tipl e wav ele ngt h c apac ity , purc has ers wis hed to s elec t iv ely us e s in gle wav elen gths to c onn ec t bra nc h l oc ati ons . This need is mos t prev alent in regi onal or fes toon ty pe s y s te ms .
By the simple addition of splitters, a PSBU is able to transmit all received wavelengths in either direction received from Stations A and B to a branch location such as Station C as shown in Figure 3. Equipment at Station C can then select the appropriate wavelength or wavelengths to use for its communications needs. Typically, the same wavelengths received at Station C are used for transmission.
By the s i mple addi tio n o f s pli tters , a P SBU is able to tra ns mi t a ll rec e iv ed wav eleng ths in ei ther direc tion rec eiv e d from St ati ons A and B to a branc h lo c ation s uc h as Sta tio n C as s h own in Figure 3 E quip men t a t S ta tion C c an then s elec t the a ppropriat e wav e leng th or wav e leng ths to us e for i ts c o m munic a tions needs . Ty p ic ally , the s am e wav eleng ths rec eiv ed a t S ta tion C are us ed f or trans m is s ion
Station A Station C Station B Fiber Pair
This k i nd o f des ign has s trong ap plic abi li ty in regi ons w here al l bra nc h l oc ati ons are no t re ady for c onnec tiv i ty a t RF P A Sev era l s tubbe d P SB U’s c an be part o f the origi nal s y s te m d eploy men t with th e ev e ntua l inte nti on of c onnec ting th os e to branc h loc a tions in th e fu ture. By bein g p ower
The major disadvantages of a PSBU with a splitter are with regard to attenuation and transmission management/control. Since all wavelengths received at the PSBU in either direction are split and passed along down the branch, a signal loss of 3dB is realized. With respect to the transmission design, each PSBU then becomes a de facto additional 15 km of cable (assuming 0.2 dB/km of attenuation in the cable). For systems with several PSBU’s, the added attenuation can require the transmission design to include additional repeaters – as such, this may significantly add to the system cost, increase the probability of a repeater failure over the life-time of the system, and increase the probability of a repeater replacement if in proximity to a cable cut or cable repair marine operation.
Conceptually, a PSBU with wavelength selection allows the purchaser/owner to manage, from a shore station, what wavelength(s) are transmitted to branch locations. The flexibility of wavelength management will afford WDM system owner/ operators the ability to dynamically increase, add, or remove wavelengths to any branch location. For regional systems that may connect many politically disparate countries, such wavelength management is a significant advantage over the PSBU’s of today which transmit all received wavelengths.
The design of a small wavelength selectable circuit for an undersea branching unit may be several years away. To achieve such a capability, active components may need to be added.
A wavelength selectable PSBU is also likely to have the benefit of low, if any, signal attenuation. Contrasted to the current WDM ilk of PSBU’s, the saving of 3dB in attenuation per device will provide the advantage of a low repeater count.
Figure 3 – Branchin g Uni t Linking All Recei ved Wavelengths to a Bra nch Sta tion
With respect to transmission management/control, the fact that all received wavelengths are passed along to the branch station by the PSBU is an advantage for a single owner/operator system. Each station at the end of a branch only needs
If the suppliers of underwater fiberoptic cable systems provide such a wavelength selectable PSBU in the future, the age of undersea switching may give rise to the next era of business growth in this industry.
Figure 2 – P owe r S witched Bra nching Unit Connecti n g 2 Fiber Pai rs to the Bra nch
With the flattening of our world’s business economy, the sharp rise in manufacturing or services in an area or country can be met with an increase in capacity through being offered additional wavelengths on an undersea cable system, Any rise in the communications needs of any two countries connected by the system can also be easily satisfied. Such a capability will likely give rise to systems being operationally usable over longer time spans since certain factors are not present that can motive obsolescence.
In the early 1990’s, the TAT-9 system employed a device called a UBM (Undersea Branching Multiplexer) that offered fiber path switching capabilities. Because of the high number of active devices, expected failure rates were much higher than what was desired for undersea components.
The underwater fiberoptic cable industry has evolved to a great extent on lessons-learned because of the cost and business impacts of mistakes. There is strong industry inertia not to design a “smart” branching unit for the reasons cited throughout this paper. Alternatively, such a “smart” branching unit may be the technology harbinger for the next growth spurt in the industry.
Significant progress is often the by-product and result of change.
Ray Chrisner has over 25 years of telecommunications experience, 15 of which have been in underwater fiber optic cable systems. As a Sr. Associate with Booz, Allen & Hamilton he led their military tactical communications survivability practice. With AT&T Submarine Systems he managed the technical responses for bids and proposals and also served as the technical project manager for FLAG. With Tyco Telecommunications, he directed the commissioning and customer services organizations, and was a manager in the quality/reliability organization. He is a certified ISO 9001:2000 auditor and is a certified
Six Sigma Green Belt. He joined WFN Strategies in 2006 as Quality Manager.
•
conference that considers the impact of high
consumption on
Repeaterless DWDM – A 317km Caribbean Festoon Segment Upgrade
By Eyal Lichtman and Michael Schneider
Introduction
Put into service in June 997 the Antillas- cable system serves the Caribbean basin and spans to link the Dominican Republic and Puerto Rico. Originally, it was designed to transmit voice, data and images at the rate of 622 million bits per second on each of its six fiber pairs. The system has been since upgraded to carry traffic at the STM-16 rate of 2.5 Gb/s per pair. Recently, Antillas- has been tested to determine how dense wave division multiplexing (DWDM) can be used to further expand the capacity of the cable system.
neutral platform that will provide the capacity needed to stimulate the growth of the Internet and other telecom services in the region.
This paper describes a field trial held by ECI Telecom and IPG Photonics in the Caribbean where eight DWDM channels at 2.7Gb/s each were successfully transmitted over a repeaterless undersea link of 317km. This is the longest span of Antillas- between the cities of Punta Cana (DR) and Isla Verda (PR).
The Undersea Link
The 317km undersea link was composed of two types of fibers: Dispersion-shifted fiber (G.653 DSF) over the first 30km of the link, and special undersea fiber (G.654, also known as Z fiber) over the rest of the link. In addition, a short piece of erbium-doped fiber (EDFA) was placed 67km before the fiber end to provide a remote optical amplification (ROPA). The undersea link is presented by Fig.a below. link, i.e. inserting the DWDM channels from the ROPA side, as presented by Fig.1b below. The link “rotation” enables the DWDM transmission since in that configuration the G.653 fiber is located at the end of the span. The signal power there is too low to cause any nonlinear degradation.
This new capacity will be used to serve a portion of the proposed Trans-Caribbean Cable Network (“TCCN”). The project was conceived to service the ever-growing Internet, data and voice traffic demands of the Caribbean. The TCCN will offer high-speed undersea fiber-optic cable connectivity from many locations in the Caribbean to Miami, Florida through a combination of segment construction and existing segment upgrades. Trans-Caribbean Cable Company (“TCCC”) is the management organization for planning, building, operating, and maintaining the Trans-Caribbean Cable Network. TCCC envisions that TCCN will become the Caribbean region’s common, carrier-
Fig.1: The original undersea link (a) and the “rotated” undersea link (b). (The upper arrow shows the signal propagation direction.
Raman Amplification
The 317km undersea link results in a loss of about 60dB that could not be passed with standard erbium-doped fiber amplifiers (EDFAs). To overcome such a high loss, ECI used both backward and forward Raman amplifiers designed and manufactured by IPG
by Figs. 2a and 2b, respectively, as a
Unfortunately, DWDM transmission was not possible due to the presence of the G.653 DSF fiber at the link input. The combination of high injection power and ultra-low dispersion of the G.653 fiber would lead to strong four-wave mixing (FWM) that would result in significant crosstalk between the DWDM channels and severe performance degradation. In order to overcome this challenge, ECI decided to ”logically rotate” the link, i.e. inserting the DWDM channels from the ROPA side, as presented by Fig.b below. The link “rotation” enables the DWDM transmission since in that configuration the G.653 fiber is located at the end of the span. The signal power there is too low to cause any nonlinear degradation.
Raman Amplification
The 317km undersea link results in a loss of about 60dB that could not be passed with standard erbium-doped fiber amplifiers (EDFAs). To overcome such a high loss, ECI used both backward and forward Raman amplifiers designed and manufactured by IPG Photonics.
thermoelectric coolers (TEC), thus providing unequalled reliability. These lasers were deployed to provide distributed Raman amplification and remote pumping of the Erbium Doped Fiber Amplifiers (EDFAs).
The OSNR gain achieved by the deployment of BW and FW Raman amplification is shown by Figs. 2a and 2b, respectively, as a function of the Raman gain.
The benefit of the backward Raman amplifier (BW Raman) is due to it low noise figure. The low noise figure of the BW Raman (<0db) enables to increase the optical signal to noise ratio (OSNR) at the link end by about 5dB when a BW Raman is deployed.
The RLT Series Raman Fiber Lasers from IPG are proven high reliability optical sources optimized for this type of application. They operate within any wavelength from 00nm to 700nm with output powers of up to 0W CW. Although a much lower power unit was used here. The lasers are manufactured using IPG’s world leading high power pump diode lasers which operate over the widest temperature range without requiring
The benefit of the forward Raman amplifier (FW Raman) is due to its immunity to nonlinear degradations. The more uniform distribution of the signal power along the fiber in the presence of FW Raman results in a partial suppression of the nonlinear threshold, thus enabling higher effective input power to the fiber and overall OSNR gain.
Fig.2: OSNR gain as a function of the Raman gain for forward amplification (b).
The Field Trial Set-up
The final field trial set-up is described by Fig.3. Using multi-service transport platform (MSTP), eight
transceivers were optically multiplexed and amplified booster (25dBm saturation power). ECI’s transceivers, C-band (1549.3nm – 1560.6nm), were spaced at 200GHz phenomena like cross-phase modulation (XPM) and four-wave
Fig.2: OSNR gain as a function of the Raman gain for backward amplification (a) and forward amplification (b).
The Field Trial Set-up
The OSNR gain achieved by the deployment of BW and FW Raman amplification is shown by Figs. 2a and 2b, respectively, as a function of the Raman gain.
Fig.2: OSNR gain as a function of the Raman gain for backward amplification (a) and forward amplification (b).
The Field Trial Set-up
The final field trial set-up is described by Fig.3. Using ECI Telecom’s flagship XDM multi-service transport platform (MSTP), eight DWDM 2.7Gb/s widely-tunable transceivers were optically multiplexed and amplified by IPG’s low-noise, high-power booster (25dBm saturation power). ECI’s transceivers, spread over the red-zone of the C-band (1549.3nm – 1560.6nm), were spaced at 200GHz in order to reduce nonlinear phenomena like cross-phase modulation (XPM) and four-wave mixing (FWM).
The final field trial set-up is described by Fig.3. Using ECI Telecom’s flagship XDM multi-service transport platform (MSTP), eight DWDM 2.7Gb/ s widely-tunable transceivers were optically multiplexed and amplified by IPG’s low-noise, high-power booster (25dBm saturation power). ECI’s transceivers, spread over the red-zone of the C-band (549.3nm – 560.6nm), were spaced at 200GHz in order to reduce nonlinear phenomena like cross-phase modulation (XPM) and four-wave mixing (FWM).
Fig.3: The field trial set-up.
The amplified channels were injected into the undersea lightwaves at 1442nm and 1480nm. The two pumps, 27dBm gain of about 6dB. The 1480nm channel was also used such high signal power – the ROPA becomes transparent). undersea link, two pump lightwaves at 1424nm and 1452nm, Raman gain of about 23dB.
set-up.
Fig.3: The field trial
Fig.3: The field trial set-up.
The amplified channels were injected into the undersea link along with two pump lightwaves at 1442nm and 1480nm. The two pumps, 27dBm each, provide a FW Raman gain of about 6dB. The 1480nm channel was also used to pump the ROPA (although at such high signal power – the ROPA becomes transparent). At the other end of the undersea link, two pump lightwaves at 1424nm and 1452nm, 27dBm each, provide a BW Raman gain of about 23dB. Tx Mux Booster Undersea line
The amplified channels were injected into the undersea link along with two pump lightwaves at 1442nm and 1480nm. The two pumps, 27dBm each, provide a FW Raman gain of about 6dB. The 480nm channel was also used to pump the ROPA (although at such high signal power – the ROPA becomes transparent). At the other end of the undersea link, two pump lightwaves at 424nm and 1452nm, 27dBm each, provide a BW Raman gain of about 23dB.
Following the BW Raman amplification, the propagating channels were amplified by a pre-amplifier (EDFA) and their accumulated dispersion was compensated by dispersioncompensating fiber (DCF) that compensates for 80% of the total accumulated dispersion. The value of the residual dispersion was optimized by numerical simulation to assure the minimal penalty from nonlinear distortion. Finally, the eight channels were optically demultiplexed on the
Fig.4: An optical spectrum analyzer trace showing the OSNR of the received channels. The lowest OSNR is 15dB
XDM platform and the received BER and OSNR were recorded.
Conclusions
Pre-emphasis and Field Trial Results
During the propagation, the DWDM channels suffer from power tilt. The power tilt is caused by the fiber wavelength dependent loss (WDL) and from gain tilt of the various amplifiers. The power tilt leads to OSNR tilt at the transmission end, thus some of the channels suffer from a low OSNR.
(OSA) trace that shows the actual received OSNR at the transmission end. As shown, the shorter wavelength channel (ITU #35) had the lowest OSNR of exactly 15dB. The Transceiver OSNR tolerance for BER of 10-2 is 9dB; thus, about 6dB of OSNR margin was achieved at this field trial.
An error-free DWDM transmission of eight 2.7Gb/s channels was performed. forward and backward Raman amplification along with a transmission-end pre-emphasis, a 6dB OSNR margin was achieved. ECI Telecom and IPG Photonics have the capacity of Antillas-1 can be increased to at least 20 Gb/s on a single fiber the originally designed capacity of 622Mb/s.
Conclusions
ECI Telecom and IPG Photonics have successfully verified the actual network against the theoretical calculations and established the optimal parameters for transmission equipment. These tests confirm eight bi-directional channels over a 317km unrepeated undersea link of the existing Antillas-1 cable system.
In order to increase the overall performance and to assure high OSNR margin for all the propagating channels, ECI performed pre-emphasis at the transmission end by using a V-Mux (optical multiplexer integrated with variable optical attenuators) on the XDM platform. The highOSNR channels were attenuated and the lowOSNR channels increased until the variance of the OSNR at the transmission end was below 1dB.
An error-free DWDM transmission of eight 2.7Gb/s channels was performed. Employing forward and backward Raman amplification along with a transmission-end pre-emphasis, a 6dB OSNR margin was achieved. ECI Telecom and IPG Photonics have shown that the capacity of Antillas-1 can be increased to at least 20 Gb/s on a single fiber pair over the originally designed capacity of 622Mb/s.
ECI Telecom and IPG Photonics have successfully verified the actual network operation against the theoretical calculations and established the optimal parameters for the actual transmission equipment.
FW Raman
BW Raman
Fig.3a: Detail of Punta Cana to Isla Verde link.
Fig.3b: Detail of Isla Verde to Punta Cana link.
These tests confirm eight bi-directional channels of 2.7 Gbps over a 317km unrepeated undersea link of the existing Antillas- cable system.
Among others, ECI is currently evaluating EFEC and Super-FEC technologies for the XDM product family. As these features are incorporated it should be possible to gain additional capacity with future upgrades to the existing system.
Summary notes:
1. Successfully transmitted 8 channels in both directions (modified spacing) of 2.7 Gbps using ECI Telecom’s 1000km dispersion widely tunable laser with dithering and G.709 forward error correction (FEC).
2. After testing a few options we concluded that the XDM’s 16-channel DWDM mux (red zone) with variable attenuation (VMUX) is required for this application for pre-emphasis.
3. Minimum OSNR margin (transmit site to receive site) is 6 dB for each direction.
4. The fiber pairs are used in the reverse direction. In other words, the G.653 fiber (DSF) is located near the receive side to reduce nonlinear effects.
5. According to the stability test the End Of Life <= 10E-12.
Eyal Lichtman is a senior member of the research and development team of ECI Telecom’s Optical Networks Division. Mr. Lichtman has more than 20 years of experience in the research of advanced optical communications systems both in the academy and the university. His main activities include nonlinear propagation in fiber optics, network design and network optimization. Eyal Lichtman holds a Ph.D. in Applied Physics from the Weizmann institute in Israel.
Michael Schneider is a marketing manager at ECI Telecom with over 17 years of experience in telecommunications. Mr. Schneider has been engaged in undersea and satellite communications projects since the beginning of his career. His latest work includes marketing ECI’s three main lines of optical transport, data networking, and broadband access products. Michael Schneider holds a B.S. degree from Systems Technology Institute in Casselberry, Florida.
THE CABLESHIPS
Letter to a friend from Jean Devos
Best and final!
My dear friend,
My Dear Friend
“Botany Bay”
Like you, I am disappointed to see how things are often conducted. Today I have in mind the culture behind or around the so called “procurement process”, and more specifically this terrible thing wrongly called “Best and final offer “(BAFO). What a terrible word. In my mother language it sounds like a “Baffe” a common word for “a slam in the face” and that is what it is. None of these 3 words – best, final, offer - are appropriated to describe this diabolic invention. It is no more an “offer,” but a rape, more often endless than “final” and never the” best”.
I published recently a modest novel, whose title is Botany Bay. It is the place in Australia where Alcatel established a submarine cable factory in 1989 as part of its contract for the Tasman 2 link. In this same bay, where two centuries before the French expedition
The “winning” supplier has no other choice but to play on this mismatch to recover a bit of money during the project implementation. I have even seen suppliers finally happy not to have been selected! Would you believe this? They prefer to concentrate on small “niche” projects where they can at least enjoy a little margin.
Warrior event was still in everyone’s memory. It is for these reasons among others that STC (UK) rejected the Alcatel‘s suggestion to come with a joint bid, to offer a “European” solution.
One of the winning factors has been the Port-Botany cable factory. Such a factory was a strong requirement from OTC (now Telstra) and the Australian Government.
The suppliers should be clearly invited to give their “best offer” at the bidding stage. That is the idea behind the bidding process and this is fair.
The “buyers” should then evaluate the various offers and select the “winner” with whom they then start to “negotiate” the deal they need, keeping the “second best” in the line.
Alcatel was the most motivated. Such a factory could expand its influence in the Pacific where the three other players were historically well established in this region, which represents a large part of their market. They saw this factory as a risk for their existing facilities!
The very first side effect of the “Bafo” game is to pollute the bidding process and clearly to increase the prices submitted at this stage. Why would suppliers come with their best prices if
“La Pérouse” made of two ships, La Boussole
they know that no decisions will be take on this basis? A smart supplier – and they are all smart - come with a “reasonable” price and then spend a lot of time, effort, and often money to collect information from inside the process so to get prepared for the coming Bafo. It also pollutes the evaluation process since it is in the” buyers” prime interest to organise leaks, false info, rumours, in view of pushing the prices down at the Bafo stage. The final winner is often not the one who came initially with the “best offer,” but the one who have the best” intelligence service”.
and l’Astrolabe, landed in 1788 to discover that Captain Cook was already around bearing the British flag. So Botany Bay is now for me the symbol of a dream which becomes a reality!
Tasman 2 has been yet another chapter in this long Anglo-French competition! The award to Alcatel came out as a big surprise to many, including inside Alcatel. Everybody was naturally expecting the British to win that battle, and such an expectation was at that time very logical.
The worse case happens when the cable owner organises the evaluation through two separated lines: the “technical” evaluation by one team, and the “commercial” evaluation by another team. There is a genetic mismatch: When one team asks for more things, more services, greater quality, the other one squeeze prices, delivery time, guarantees, etc.
There were so many difficulties and misunderstanding between Australia and France, the main one being the French presence in the Pacific area, the worse being the nuclear bomb experiment in Tahiti! The sad Rainbow
I hope that the present paper will stimulate a debate on this subject which could find its conclusion at SubOptic 07. It would be the honour of our community to adopt a more civilised procedure. My intention is to show up in Baltimore next year, wearing a tee-shirt labelled “Mort au Bafo”. I invite you to join me.
SubOptic ‘87 in Versailles came at the right time. It is where the Australian teams discovered the French model, a close cooperation between Alcatel and FT, exactly what they wanted to establish in their country.
Your friend,
Jean Devos
My friend, things are changed since, but one thing stays true: When you offer something, the reader can see between the lines if you are or not genuinely motivated and sincere. Then your offer becomes really attractive and this opens the route to “Botany Bay.”
