Annual Report 2019
| Introducing the Future Photonics Hub
Contents Introducing the Future Photonics Hub
03
Our mission
04
Executive summary
06
The ultimate enabling technology
08
Core technology platforms
10
Innovation Fund
12
Research income
14
National leadership
16
Photonics for the next generation
20
The Future Photonics Hub is a partnership between two leading UK research institutes, the Optoelectronics Research Centre at the University of Southampton and the EPSRC National Epitaxy Facility at the University of Sheffield.
Communications 26 Technical reports
28
The team
46
We work with a network of over 40 companies, representing strategic UK sectors including telecommunications, healthcare, defence and aerospace, to support the rapid commercialisation of innovative photonics manufacturing technologies. Together, we are combining our expertise and state-of-the art experimental facilities to:
■
■
■
ead research in core photonics L platform technologies: silica optical fibres, III-V semiconductors, silicon photonics, 2D materials and metamaterials. evelop integrated manufacturing D processes, making it simple and efficient to incorporate photonics into high-value systems. und early stage research into F cutting-edge manufacturing technologies.
3
| Our mission
We aim to secure the UK’s position as a leading innovator in the high value global photonics market by transferring new, practical and commercial process technologies to industry.
We respond to the needs of industry by creating new photonics materials, devices and components, designed to be easy to manufacture and integrate with existing technologies.
We bridge the gap between academic research and product development, uniting the UK science base with industry and funding agencies to co-invest in R&D.
We use innovation in light technologies to accelerate growth in the UK’s £13.5 billion photonics industry and support £600 billion of UK manufacturing output across key global market sectors.
4
5
| Executive summary
Together we are maximising the impact of Government investment and continue to make great strides in uniting the UK photonics community. In 2019 we have
Awarded over £150,000 in grant funding to stimulate innovative photonics manufacturing research.
Refined techniques to join revolutionary new hollowcore fibres with conventional solid core fibres so that their unique properties can be harnessed to transform telecommunications and industrial processing.
Worked on 16 new research projects with industry.
In the three years since launch, we have more than tripled the impact of our initial Government investment. We have generated £15 million of income from industry and are working on 72 research projects to help bring new photonics technologies to market. We have also been awarded an additional £11 million in competitively won grant funding to further accelerate next generation manufacturing research.
Generated a total of £3.8 million industrial income.
Delivered handson photonics workshops for 900 school pupils and teachers.
Established methods to manufacture silica fibre lasers for use in laser based surgery.
6
Made substantial advances in semiconductor processing technology to produce integrated Quantum Cascade Lasers for gas detection.
Developed new ways of manufacturing emerging 2D materials on a large scale.
“We know from experience the astonishing range of innovative ideas that emerge when scientists and engineers come together to think about manufacturing. Scientific discovery is only ever one part of the solution. It’s important to remind ourselves, why we are doing this, where it’s leading and what it can do for UK industry.” Professor Sir David Payne Director, The Future Photonics Hub
7
| The ultimate enabling technology
Photonics has near limitless uses and can be found in almost all of the products and services we use in everyday life. Photonics is the science and technology of light. Although most people don’t realise it, photonics technologies are widely integrated into products and systems across a broad range of sectors.
Enabling key industry sectors
Employment
Output
£13.5bn
69,000
£5.3bn
industry value to the UK economy
Harsh environment sensors for oil & gas
Here are just a few examples of the many applications of photonics technologies:
Value
Optical fibres for high bandwidth telecommunications
Laser-written diagnostics for healthcare
Silicon photonics for data centres Sensors for security
High power fibre lasers for manufacturing
total GVA
£76,400 GVA per employee
8.4%
like for like growth over two years (4.1% CAGR)
(vs UK manufacturing average of £67,000)
UK photonics manufacturing industry Putting the UK at the forefront of future industries
LIDAR for autonomous vehicles
people employed across the sector
Growth
The UK is an international leader in photonics research. Our science base has already given rise to a globally significant market which continues to expand at an impressive rate.
Photonics technologies are both ubiquitous and transformative. The UK photonics manufacturing industry is growing, as are many other high-tech industry sectors enabled by photonics. Investing in future photonics innovation is critical to retaining the UK’s competitive edge in the £400 billion global photonics market and offers vast potential to stimulate wider economic growth.
Source: The Photonics Leadership Group (PLG), June 2019
Head-up displays for aviation 8
Integrated photonics for quantum technology
9
| Core technology platforms
We are developing new photonics technologies to fuel industry innovation. Our research is delivering solutions to manufacturing challenges and overcoming barriers to the widespread industry adoption of next generation photonics. We aim to develop the important ‘Pervasive Technologies’ identified in the UK Foresight report on the future of manufacturing1, through carrying out research into four, carefully selected Technology Platforms: High Performance Silica Optical Fibres, Light Generation and Delivery, Silicon Photonics and the Large Scale Manufacturing of Metamaterials and 2D Materials. We also know that the key to producing low cost components and systems is integration. Optical fibres, planar waveguides, metamaterials and III-V semiconductors cannot yet be combined in a cost effective, integrated manufacturing process.
10
Our consultations with over forty companies, Catapults and Innovative Manufacturng Centres identified a clear business need to reduce the complexity of incorporating next generation photonics technologies in high value systems. Integration is an industry wide issue which we have chosen to tackle as our ‘Grand Challenge’. Our research capabilities The Hub is a unique partnership between the Optoelectronics Research Centre (ORC) at the University of Southampton and the EPSRC National Epitaxy Facility at the University of Sheffield. It is this collaboration between two leading research institutes that ensures our work is characterised by scientific excellence and innovation. Together, we have an extensive and impressive track record in research and enterprise:
■
■
■
■
■
ur innovations navigate airliners, O cut steel, mark iPads, manufacture life-saving medical devices and power the internet. ur optical fibres, invented and O made in Southampton, are on the Moon, Mars and the International Space Station. ur epitaxial wafers and devices, O produced in Sheffield, have enabled world-class semiconductor research in the UK since 1979. ur combined portfolio of startO ups now exceeds 12 companies. ur expertise is underpinned by O our £200 million of state-of-the-art fabrication facilities.
Core Technology Platforms 2. Light Generation and Delivery 1. Large scale manufacturing of Metamaterials and 2D Materials
User-driven manufacturing processes will increase the integration and unification of diverse manufacturing platforms in III-V epitaxy, metamaterials, Si-SOI fabrication methods and functional fibre geometries.
Developing cost-effective, reliable and volume-scalable methods to fabricate these novel materials in order to enable their practical exploitation in applications such as telecommunications, displays and sensors.
Grand Challenge: Integration The drive to achieve integration is a ubiquitous theme uniting the world’s photonics industries. The photonics industry today can be likened to the early days of electronics when individual components were wired together, resulting in inevitable cost and scaling implications. Today’s photonics components are not yet compatible with a single manufacturing platform and this represents a major industrial challenge.
3. High Performance Silica Optical Fibres
4. Silicon Photonics
Optical fibres are essential components in many photonic devices and systems – from sensing to amplifying light. The key challenge in manufacturing fibre is improving its loss, gain and power handling characteristics.
Achieving integration with optical fibres, light sources and key processes of wafer level manufacturing to enable devices such as low cost transceivers for data centres and mid-infrared sensors.
11
| Innovation fund
With support from our £1 million Photonics Innovation Fund, we are building a national network of academic partners, equipped to respond to emerging industrial challenges.
The Future Photonics Hub University of Southampton University of Sheffield Innovation Fund partners Heriot-Watt University University of Bangor
Since 2016, we have awarded a total of £750,000 in grant funding to projects led by UK researchers offering new capabilities relevant to industry but outside of our core expertise. Our dynamic funding mechanism operates using an annual call for proposals, aligned with specific research themes. Our fourth call launched in October 2019 and was a collaboration with three other EPSRC Future Manufacturing Research Hubs; the Future Composites Hub, the Future Compound Semiconductor Manufacturing Hub, and the Future Metrology Hub. The joint call created new possibilities to exploit research synergies by inviting proposals involving multiple Hubs and offering funded projects access to a wider range of facilities and equipment.
We received a total of 13 photonics research proposals from ten UK institutions in response to the 2019 call. The applications were reviewed by a panel of co-investigators and independent assessors, using a common framework agreed by all four Hubs. The assessment criteria included: suitability to the call and appropriate TRL level; research quality; scientific novelty and timeliness; relevance to industry and building UK manufacturing capability; ambition, level of risk and potential for similar levels of return; appropriateness and credibility of the team to deliver and future develop the project; and planning and resources. We awarded a total of £153,000 to the three top-ranked projects: ■
‘ Growth of large Pockels coefficient PZT and BTO layers on Si’, Prof Hayden, University of Southampton. Award value: £62,259
■
■
‘ Mid-infrared diamond integration photonics: a feasibility study.’ Dr Maziar Nezhad, University of Bangor. Award value: £59,965
University of Bristol University of Cambridge University of Oxford University of Southampton with Imperial College, London
‘ Integration of 2D materials with established silicon photonics and electronics platforms’, Dr Ioannis Zeimpekis-Karakonstantinos, University of Southampton. Award value: £30,890
University of Southampton with Phoenix Photonics University of Strathclyde Industry partners International industry partners by country
In addition, we pledged support to a fourth project:
UK photonics industry activity
‘Manufacturing of large area InP on nano-V-grooved CMOScompatible Si’, led by Dr Philip Shields at the University of Bath. This was submitted as a joint proposal to the Future Compound Semiconductor Manufacturing (CSM) Hub and us. The CSM was selected as the lead funder for the project based on a closer alignment of research priorities (award value: £62,476). Sweden China
*Grants funded at 80% FEC
12
USA
Italy
13
| Research income
Industrial income by Technology Platform
Innovating with industry for economic growth. As national leaders in photonics manufacturing research, we stimulate collaborations between academia and industry throughout the supply chain.
£4m+
£4,897,000
£920,000 £651,000
2016-2018
72
High-Performance Silica Optical Fibre Light Generation and Delivery Silicon Photonics Large-Scale Manufacturing of Metamaterials & 2D Materials Integration
2019 income £3,331,000 2019 income £1,728,000 2019 income £972,000 2019 income £153,000 2019 income £220,000
Total income January 2016 to December 2019
2016-2018
industry sectors 2016-2019: sensing, defence, photonics, data comms, storage, LIDAR for autonomous vehicles, aerospace, advanced materials and manufacturing
£15m 41.5% Industry income
2019
14
£5,095,000
£3,755,000
Our ramped-up activities under the Grand Challenge of Integration have also been supplemented by some targeted projects following the award of funding from the Defence and Security Accelerator (DASA).
projects, 4 Technology Platforms 2016-2019
9
Total income
£15m+
2019 industrial income
2019
2019
Total industrial income
2019
We engage industrial influencers to raise awareness of the value of photonics, both in delivering transformational manufacturing technologies and driving economic growth.
We have secured significant income in all four Technology Platforms, working with companies across the photonics supply chain from component manufacturers to large end users in a range of market sectors.
2016-2018
£10m
28% core income
£11m
30.5% competitively secured income
2016-2018
15
| National leadership
We have an important responsibility to provide leadership within the photonics manufacturing community and to act as leaders in our field for industry, academia and government. As national leaders, our role is to increase awareness of how photonics manufacturing research tackles Grand Challenges, improves people’s lives and boosts productivity. We provide a ‘go-to’ source of expertise which helps industry innovate, and we advocate strategic investment in photonics manufacturing research to drive social and economic impact.
Centre: Professor Graham Reed, SPIE Photonics West
16
Raising awareness Getting out to conferences and trade shows is a powerful way to interact with stakeholders and represent the community on a global stage. Since 2016, we have participated in 97 conferences, trade shows and workshops around the world, giving invited talks, presenting papers and exhibiting technology demonstrators.
In 2019, we took our research to some of the largest and best-known international conferences. Hub Co-Investigator Professor Graham Reed chaired the prestigious OPTO Symposium at SPIE Photonics West in San Francisco, one of the world’s largest photonics conferences with 23,000 attendees. There was a strong presence from the Hub across the conference and we achieved an impressive 11 papers accepted to the programme. We also travelled with our technology demonstrations to SPIE Defence and Commercial Sensing in Baltimore and Laser World of Photonics Munich, where, as part of the UK Pavilion, we showcased the UK photonics manufacturing capability to the exhibition’s 34,000 visitors.
In addition to our physical presence, we have a growing voice online and in the media. Through social channels, newsletters and the press, we are initiating discussions and providing thought leadership on contemporary issues, such as UK investment in R&D and diversity in the technology sector. In June, we released updated figures quantifying the size and economic impact of the UK photonics industry. These have since been widely referenced in the trade press and used by academics and industry alike. In October, we supported the Royal Society’s ‘Transforming our Future: Photonics’ scientific meeting in Cardiff by providing all delegates with copies of our latest market report.
17
| National leadership
Increasing engagement
Championing photonics
We act as a beacon for the UK photonics manufacturing and enduser communities by organising events and meetings which stimulate research collaborations.
As recognised leaders in our field, we ensure photonics is positioned within the wider debate on UK manufacturing and the economy. We use our high profile and expertise to demonstrate the potential for advances in photonics to generate significant social and economic impact and to articulate its alignment with issues of strategic national importance.
In June, our Deputy Director Professor Jon Heffernan, and Industrial Liaison Manager, Dr John Lincoln, co-chaired the first unclassified day of the Electronic Warfare Technology Conference in Shrivenham, a key meeting of major stakeholders in UK defence. The programme of speakers, drawn from across UK academia, reviewed the manufacturing readiness of the latest photonics innovations with potential impact in the defence sector. Our 2019 industry day was held in Sheffield, co-organised with the annual UK Semiconductors Conference. 280 delegates and 70 exhibitors participated in the two day event, which featured a technical programme of major research developments, forthcoming funding opportunities and a review of the UK photonics manufacturing industry landscape. Throughout the year, we targeted increasing research income to the UK academic community. We launched our Innovation Fund at Photonex in October and worked with the Knowledge and Transfer Network (KTN) to host a national briefing and consortium building event in preparation for forthcoming Horizon 2020 ICT calls.
18
In April, Professor Sir David Payne delivered a keynote address on The Future of Photonics at the Annual General Meeting of the European Photonics Industry Consortium (EPIC). He provided commentary and insight into challenges and opportunities for the sector, raising the profile of UK photonics manufacturing research to 200 industry representatives from 20 countries. Sir David was also a panel member for the Royal Society’s ‘Transforming our Future’ scientific meeting series, participating in the discussion on new directions and applications of photonic technologies. This event is just one example of our continuing work to shape and encourage the dialogue around horizon-scanning. We joined the All Party Parliamentary Group (APPG) on Photonics, Westminster Showcase in July and met with over 30 MPs and parliamentary aides to raise awareness of the UK’s strong photonics manufacturing industry and its potential to drive economic growth. Following from the event, APPG Chair Dr Carol Monaghan MP gave the plenary presentation at our ‘Silicon Photonics: Academia and Industry Working Together’ conference in October.
19
| Photonics for the next generation
Outreach and public engagement brings photonics research to diverse audiences outside academia, from pupils and teachers in schools, to community groups like the Girl Guides and the general public. We aim to: ■
■
■
i ncrease public understanding of photonics and its vital role in everyday life; r aise the number of people studying STEM subjects; and,
In 2019 we have reached nearly 5,000 people at 37 events. Our key audiences were members of the public at festivals and large-scale events (3,390), and school pupils (900 in 27 schools), predominantly in Key Stages 3 (11-14 years) and 4 (aged 14-16 years).
2019 Outreach and public engagement audience groups
1%
Professionals
1% Teachers
We have taken photonics to schools, colleges, sciences fairs and arts festivals, a cathedral, and even a pub. With support from the European Commission, the Institute of Physics, the Royal Academy of Engineering, the University of Southampton’s Widening Access Team and the Public Engagement with Research Unit (PERu), we have delivered a highly differentiated suite of activities, engaging a wide variety of audiences.
elp our own researchers h develop valuable skills, such as communication and project management.
Nearly 1,000 school pupils and teachers have taken part in our hands-on workshops. These include the Photonics Music project, designed by Hub PhD student
710
Other Audiences
20
900
School children
5%
Key Stages 5
19% 14% Key Stages 3
Andrei Donko, and ‘Phablabs 4.0’, which draws on the growing network of ‘Maker’s Labs’ to provide space for young people to develop practical skills. Outside of the classroom, we have worked with thousands of members of the public at festivals such as Southampton Science and Engineering Day, Winchester Cathedral Science Fair, ‘Light Up Poole!’ and the ‘Pint of Science’. All of our activities are designed to spark an interest in photonics amongst people of all ages and backgrounds. Our goal is to inspire
Key Stages 4
60% General public
people either to personally consider pursuing STEM subjects or to encourage others in their lives who may be thinking about further study. We evaluated our activities to see how much participants had enjoyed them; what they had learned and whether the activities had wider impact. Participants gave our workshops an average of 8/10 for enjoyment; over 70% agreed that they had learned something new about physics and photonics; and more than 60% said they would share the experience with their friends and family. Participants learned new skills with electronics and computer programming during our workshops.
3,390
General public
21
| Photonics for the next generation: photonics music case study
PhD researcher Andrei Donko has been using sound and music to inspire young people to learn about photonics and gain practical engineering skills. With funding from a Royal Academy of Engineering’s Ingenius grant, Andrei and his team of engineers invented three fullyplayable, musical instruments - the Light Harp, Laser Guitar and Rhythm Kit. The instruments were designed to make sound using fundamental principles of photonics and could be constructed from basic hardware, typically found in Andrei’s own research environment.
The team created 100 DIY kits for schools, containing all the materials needed to make the instruments in a series of five, one-hour workshops. Between March and July 2019, the team delivered 19 workshops in four secondary schools, helping pupils build the instruments while developing practical skills in soldering, electronics, programming, problem solving and independent working. 116 pupils participated in the school workshops, 85% from underserved audiences.
“The sessions were excellent, they were engaging for the students and gave them insight into engineering and problem solving. They also fitted in well with our scheme of work at school as they had been learning about light at the time in lessons.”
A further 295 school pupils, aged 11-16, took part in workshops while attending ‘Why Higher Education?’ visit days. These events, held at the University of Southampton, were organised by the Widening Participation team to engage with pupils from areas with typically low university participation. The instruments created during the project were displayed at the ‘Light Up Poole! digital arts festival, and Southampton Science and Engineering Festival. Of the 2,177 people who interacted with instruments at these events, 90% reported having learnt something new and 80% said they had a better understanding of how our research could affect their lives.
School pupils making holograms in a photonics workshop
Teacher participating in a Photonics Music workshop
22
23
| Photonics for the next generation: pop-up Photon Shop case study
A team of physicists and optical engineers transformed an empty store unit into a pop-up Photon Shop, packed with handson activities for the public to experiment with light technologies. As part of ‘Light Up Poole!’, a three-day digital arts festival, the Photon Shop used interactive fibre optics, holograms, smartphone 3D projectors and LED musical instruments to capture the public imagination around fundamental physics and photonics in everyday technologies. The shop welcomed 1,070 visitors during its nine hours of opening. Many adults attended alone or in family groups, as either parents or grandparents accompanying young children. Half of all visitors were under the age of 16.
“We learned how the internet worked with lasers.” Female Photon Shop visitor
24
The shop created a space to engage with audiences that may not be considering higher education, either as an option for themselves or for their children. 30% of visitors were from Central Poole, an area where the majority of postcodes fall within POLAR4 quintiles 1-3, the lowest higher education participation areas, and have multiple deprivation indices. When asked what new learning they would take away from the shop, most visitors reported discovering for the first time that lasers are used in powering the internet. The festival also featured on ‘BBC South Today’ news, where it was watched by some 500,000 people.
Visitors to Photon Shop
35%
under 6 year olds or 60 year olds
30% 6-11 year olds
35%
30-59 year olds Pop-up Photon Shop, ‘Light Up Poole!’
25
| Communications
We continue to focus on clear and timely communications with other academics, industry and the wider public. Telling our stories through the media In 2019, we issued a series of seventeen press releases to academic and scientific media outlets, announcing our latest research developments and events in our national leadership programme of activity.
Image courtesy of Christopher Pledger, The Telegraph.
26
We were approached by The Telegraph’s Technology News Editor, Ellie Zolfagharifard in August to provide expert opinion for an article on UK hotspots for technology innovation. ‘Why Southampton has what it takes to lead the UK’s tech revolution’ featured interviews with Professor Sir David Payne, Professor Dave Richardson and Professor Graham Reed on pioneering tech start-ups such as Southampton spinout and Hub collaborator SPI Lasers. The piece, which was published both online and in print, also highlighted the cutting-edge capabilities of the University’s multi-million-pound cleanrooms.
Raising our profile through our internationally renowned research team Hub Co-Investigators have continued to receive recognition for their outstanding contributions to photonics research and industry innovation. Professor Graham Reed won the PIC Individual Contributor Award, voted for by industry peers and influencers at the 2019 Silicon Photonics PIC International Conference in Brussels. Professor Nikolay Zheludev featured in the Clarivate Analytics’ Highly-Cited Researchers. This esteemed accolade recognises researchers whose publications are in the global top 1% of citations, reflecting the significant influence of Professor Zheludev’s career over the past two decades. In October, Nikolay was also recognised by the United States National Academy of Engineering (NAE) for his leadership and technical contributions to optical materials and nanophotonics, becoming only the 43rd UK-based engineer to be named as a member.
Professor Dave Richardson and Professor Zheludev were both elected as Royal Society fellows in 2019. These prestigious accolades recognise individuals who have made a substantial contribution to the improvement of natural knowledge, including mathematics, engineering science and medical science. Amplifying messages through digital media We sent a regular electronic newsletter to our subscribers throughout the year, keeping them informed of the latest news, events, funding opportunities and expert opinion pieces. The publication’s open and click-through rates continued to be more than double those of manufacturing sector benchmarks for email communications, with average open rates of 42% and click-through rates of more than 12%. The @ PhotonicsHub Twitter account continues to actively engage a growing following as we work to use the channel to share news and participate in the vibrant, diverse online community.
27
Technology reports Hollow-core fibre efficient power launching schemes
30
Novel forms of interconnection and device integration for emerging multicore and hollow core fibres
33
Developing efficient thulium and holmium-doped silica fibres for high power lasers at 2 microns
35
Active and hollow core fibres based on non-silica glasses
37
Mid-infrared silicon photonics components for low cost sensing systems
39
Wafer-scale manufacturing protocols for emerging 2D materials
41
Developing integrated mid-infrared on-chip photonics
43
Images in University of Southampton’s £200m Cleanrooms
28
29
| High Performance Silica Optical Fibres
| High Performance Silica Optical Fibres
Hollow core fibre efficient power launching schemes Challenge
Progress
Photonic bandgap and anti-resonant hollow core fibres have revolutionised data centres and telecommunications, and provided a new impetus in high power delivery for industrial applications. Joining these new hollow core fibres to more conventional solid core types is an important issue. Whilst a number of different techniques have been demonstrated, they are mainly limited to lower powers.
We have developed two joining techniques which are scalable to high powers and enable solid core and hollow core fibre to be robustly spliced together. They are also suitable for efficiently launching both fundamental and higher order modes. Our first method, shown in Figure 2b, involves creating a properly truncated taper in the solid core fibre, enabling it to be inserted into the central air gap of the hollow core. The tapering provides adiabatic mode transformation and mode field diameter (MFD) matching, thereby minimising scattering losses and backreflections. Critically, it is capable of high power operation and long distance delivery.
Co-Investigator contact: Professor Michalis Zervas mnz@soton.ac.uk
Figure 1: A solid core to hollow core fibre joint by (a) butt-coupling, (b) tapering. Most current approaches rely on direct butt-coupling, as shown in Figure 1a, or bulkoptics imaging systems matched to the fibre’s guided modes. However, both these techniques can be problematic. Direct butt-coupling inevitably results in excess radiation losses and ~4% back-reflections, whilst bulk-optics demand fine alignment and can be less stable long-term. The challenge is to achieve efficient launching of high power in the kilowatt to multi-kilowatt range.
30
Figure 2: (a) Truncated taper MFD vs taper tip cladding diameter; (b)(e) selected output mode images.
Figure 2a shows very good agreement between the experimental and theoretical MFD at the truncated taper tip output, plotted against the taper cladding diameter. The maximum MFD of 18.5 μm is achieved with a cladding outer diameter of 35 μm, making this truncated taper suitable for launching into a 35 μm hollow core fibre. The optimum taper tip size corresponds to the inner core diameter, showing fast MFD expansion and results in the maximum possible MFD size. Further decreasing the outer diameter of the taper results in a smaller MFD size. The 35 μm tip makes the truncated taper mechanically robust and importantly, overcomes the mechanical stability problems associated with extra-thin tips (down to 200-300 nm) previously reported in the literature.
31
| High Performance Silica Optical Fibres
| High Performance Silica Optical Fibres
Another key feature of our method is that it can produce a variety of tip sizes and MFDs to suit hollow core fibres with different air gap cores. We achieved this by using solid core fibres with different initial core and cladding diameters.
Novel forms of interconnection and device integration for emerging multicore and hollow core fibres
Figure 3 plots the MFD variation at the taper tip against the initial outer cladding diameter, varying between 125 – 200 μm. We have shown that increasing the initial untapered cladding diameter from 125 μm to 200 μm, increases the MFD from ~15 μm to ~23.5 μm. This is suitable for launching into hollow core with air guiding holes varying between 35 μm and 45 μm. Our second, alternative method involved using truncated tapers in conjunction with long period gratings to turn fundamental into higher order cladding modes (HOMs) adiabatically at the tip, and then subsequently exciting HOMs in the hollow core fibre. Using a large truncated taper tip provides mechanical rigidity and therefore enhances stability and robustness. Our initial tests with the truncated tapers shown in Figure 2 have resulted in efficient launching into short lengths of hollow core fibre. We are now undertaking extensive experimental work using tapered fibres with different initial core and cladding diameters, tailored to launch into suitable anti-resonant hollow core fibre, made in Southampton.
Challenge Developing innovative ways to interconnect new, emerging varieties of optical fibre with more established fibre types and functional components.
Figure 3: MFD variation at the taper tip versus the taper tip cladding diameter, for different initial untapered core/cladding diameters.
Progress
Co-Investigator contact: Professor David Richardson djr@orc.soton.ac.uk
Using multicore, few mode fibre, (7 cores x 6 modes), we have developed integrated components including microcollimator-based 7 core x 6 mode isolators and pump beam dumps, designed to reduce excess pump power in cladding pumped MCF devices. We have incorporated these components into two high channel count multicore fibre (MCF) erbium-doped fibre amplifiers (42 spatial channels), which were successfully deployed in various data transmission experiments by our collaborators at NTT Laboratories, Japan (1 L-band and 1 C-band amplifier). We have also produced and shipped various prototype MCF couplers and few mode amplifier assemblies to our industrial partner Phoenix Photonics.
Figure 4: MFD variation at the taper tip, versus taper tip cladding diameter.
Figure 1: Example meta devices.
32
We have concentrated on integrating the two main kinds of novel fibres developed by our fellow researchers: multicore optical fibres, which incorporate many spatial paths within the fibre cross-section, and hollow core fibres, including hollow core photonic band gap (HC-PBGF) and anti-resonant fibre variants.
We have made progress in integrating MCF with metamaterials, developing a device with 7 cores incorporating meta-surfaces for polarisation analysis and control (see Figure 1). This device has shown good coupling performance and individual core access. Furthermore, we have demonstrated a coherent absorber device using an integrated meta-surfaced fibre with a micro-optic collimator assembly.
33
| High Performance Silica Optical Fibres
| High Performance Silica Optical Fibres
Developing efficient thulium and holmium-doped silica fibres for high power lasers at 2 microns Micro-collimator technology was also used in conjunction with digital micromirror display devices to demonstrate a number of low cost functional components. These included a MCF attenuator which can be tuned on a per core basis, i.e. as needed for independent channel gain control in an MCF amplifier, and a similar device for few mode fibres, offering differential attenuation on a per-mode basis. We are now in the final stages of working on a low cost beam measurement system based on the same DMD technology. Our latest results have shown excellent performance across a wide range of wavelengths, from one to beyond two microns. In collaboration with Czech Technical University in Prague, we have developed a gluing based technique to reduce losses at the interconnection of hollow core and single mode fibre to less than 0.3 dB per joint. Our method is compatible with low temperature processing and has been applied successfully to both HC-PBG and anti-resonant fibre,, whilst also achieving low back reflection values. In addition, we have demonstrated a range of functional hollow core fibre components, including two-port devices such as integrated optical isolators and filters, and three and four port devices, such as a beamsplitters and WDM couplers (see Figure 2). Excess losses are currently between 0.5-1 dB with <-30dB levels of back reflection and <25 dB high order mode excitation. Over the next year, wewill continue to explore integration in both of these major new fibre types, aiming to reduce losses even further and increase device functionality.
34
Challenge The market for high power fibre lasers is dominated by sales into the manufacturing sector. For many years, lasers operating in the ~1 μm wavelength region have been used for materials processing applications. However, more recently interest has been growing in processing certain kinds of materials, such as plastics, using 2 μm lasers.
Co-Investigator contact: Professor Jayanta Sahu jks@orc.soton.ac.uk
Figure 2: Example hollow core fibre components.
μm provides the optimal absorption characteristics in plastics for controlled material 2μ processing. In contrast, absorption in the wavelength regions offered by ytterbium fibre and CO2 lasers,that operate at wavelength of ~1 μm and ~ 10 μm respectively, is either too low or too high in many plastics. 2 μm lasers are also capable of performing efficient superficial tissue ablation and therefore present attractive solutions for laser based surgery. Both thulium (Tm) and holmium (Ho)-doped silica fibre lasers emit in the target 2 μm waveband. Tm-doped fibre lasers provide excellent performance around 2 μm, though achieving efficient operation above ~2100 nm is a challenge, whilst Hodoped fibre lasers provide extended coverage into the atmospheric transmission window between 2100 and 2250 nm. This window is of interest for free-space beam propagation applications, such as remote sensing. Eye safety is an important consideration in such applications and 2 μm emission is strongly preferred over more conventional 1 μm sources. In-band pumping using Tm-doped ~1.95 μm fibre lasers is one of the most common pumping schemes for high power Ho-doped fibre lasers. In this kind of architecture, the wall-plug efficiency of the laser (i.e. the electrical to optical power efficiency) depends directly on the efficiency of the Tm-fibre. In-band pumping also brings additional challenges to Ho-doped fibre fabrication since an all-glass structure must be used. This is due to the high absorption of standard low-index polymers typically used in double clad fibres at 2 μm.
35
| High Performance Silica Optical Fibres
| High Performance Silica Optical Fibres
Active and hollow core fibres based on non-silica glasses In contrast, thulium-holmium (Tm:Ho) co-doped fibres can benefit from direct high power laser diode pumping at around ~793 nm. Prior to this work, efficiencies of up to 42% had been reported for cladding-pumped Tm:Ho co-doped silica fibre lasers.
Progress We have focused on engineering core glass compositions for Tm and Tm:Ho codoped silica fibres, suitable for efficient high power laser operation at 2 μm, when diode-pumped at 793 nm. We have fabricated fibres using a novel hybrid gas phasesolution doping process in conjunction with the modified chemical vapour deposition (MCVD) technique pioneered by our team in Southampton. This method for fabricating speciality optical fibres is easy for fibre manufacturing industries to adapt. We have demonstrated Tm-doped fibres with an effective two-for-one cross-relaxation process when cladding pumped at 793 nm, and have achieved laser efficiencies at 2 μm exceeding 72% (90% of the theoretical efficiency). We have also investigated varying the Tm concentration and Tm to Ho ratio in Tm:Ho co-doped fibre lasers operating beyond 2.1 μm. Our aim is to achieve an efficient two-for-one cross-relaxation process in Tm, coupled with an efficient Tm to Ho energy transfer process. To date, we have achieved laser efficiencies of 56%, using a Tm concentration of 5.5 wt% and ~ 1:10 Tm:Ho ratio.
36
Challenge To exploit the advantages of compound glass over more conventional silica varieties to produce hollow core and active solid core fibres, suitable for applications in super compact optical amplifiers and the mid-infrared wavelength region.
Progress Our research into anti-resonant hollow core microstructured fibre (AR-HCF) has focused on two different types of glass: a Tellurite composition, developed in-house and a commercially-sourced chalcogenide glass alternative (IG3, Ge30As13Se32Te25). Tellurite is durable and non-toxic. It has a transmission edge extending well beyond silica, providing a mean for low-loss AR-HCF for power delivery applications extending to ~6 μm. Chalcogenide glass AR-HCF could potentially combine a low loss and high power laser delivery capability up to 12 μm.
Co-Investigator contact: Professor Francesco Poletti frap@orc.soton.ac.uk
We have developed and perfected a single step preform extrusion fabrication method which reliably produces regular preforms, incorporating a fluorinated polymer coating co-drawn with the fibre. This technique protects the glass from the external environment and addresses safety concerns arising from glass toxicity. It has also enabled us to improve the mechanical properties of the fibre, including strength and flexibility. We have been routinely drawing fibre with a symmetrical structure suitable for guiding light in the near-IR at attenuation levels of a few dB/m, and with good single mode properties.
37
| High Performance Silica Optical Fibres
| Silicon Photonics
In the field of active, solid core fibre, our aim was to develop a simpler alternative to pure or doped silica, for use in producing highly doped fibres using non-silica glass hosts. Such fibres have promise in compact amplifier applications as they can amplify very short pulses of high peak energies, without introducing undesired nonlinear effects. Preform extrusion fibre fabrication Tellurite glass billet 28x37mm
Extruded tellurite preform
Fabricated tellurite fibre
36cm long preform Extruded IG3 preform
IG3 glass billet 28x37mm 33cm long preform
Figure 1: Hollow core extruded tellurite and chalcogenide fibres
Fabricated IG3 fibre
We have significantly improved on last year’s reported Tm3+ doped germanate glass single mode fibres. We achieved a Tm3+ doping concentration of 8.5 x 1020 ions/cm3, the highest ever reported in this glass type. Through optimising the composition and Tm-doping concentration, we have produced highly stable glasses, able to withstand the double thermal cycle necessary for fibre fabrication without any signs of crystallisation. This ensures long lifetime and excellent overall amplifier/laser performance in the shortest possible fibre device. The fibre’s low-numerical aperture (NA = 0.07), large mode area (core diameter of 17 μm), and double cladding were designed to facilitate its use in a cladding-pumped configuration. Our initial experiments using this fibre as the last amplification stage in a 2 μm laser master oscillator power amplifier (MOPA) chain have yielded encouraging results and show promise for future high power ultrashort fibre device applications. We will continue to focus on improving both these fibre types. Our aims are to achieve hollow core fibres with ~dB/m loss in the mid-IR and demonstrate the advantages of double clad germanate fibres in practical ultra-short pulse amplification.
Figure 2: Highly Tm-doped Germante double clad fibre.
38
Mid-infrared silicon photonics components for low cost sensing systems Challenge The mid-infrared (mid-IR) spectral region is of interest for applications in gas, chemical and biomedical sensing. We have focused on tackling three key research challenges to enable the realisation of inexpensive, handheld and robust optical sensing systems. These challenges are: integrating active photonic components, such as Quantum Cascade Lasers, with passive circuits based on a Ge-on-Si platform; realising suspended Ge platforms for broadband spectral operation; and fabricating high speed optical modulators suitable for longer wavelengths.
Progress
Co-Investigator contact: Professor Goran Mashanovich g.mashanovich@soton.ac.uk
We have focused on integrating Quantum Cascade Laser (QCL) bars, fabricated by the team in Sheffield, with our Ge-on-Si based platform developed in Southampton. Integrating QCLs allows for more complex circuits to be realised on a chip. We have designed Ge photonic circuits and devised an integration scheme, shown in Figure 1. The fabrication is currently in its final stage and the flip-chip integration of QCLs with Ge waveguides will be completed soon. This will provide a proof-of-concept for future work integrating several QCLs, emitting at different wavelengths. Figure 1: Schematic of a QCL flip-chip bonded to a Ge-on-Si platform.
39
| Silicon Photonics
| Large-Scale Manufacturing of Metamaterials and 2D Materials
Building on our previous research into suspended Si devices with sub-wavelength gratings (SWG) and metamaterial lateral cladding, we have developed a suspended Ge platform (See Figure 2). This has enabled us to make significant progress towards demonstrating suspended Ge waveguides at 3.8 μm and 7.7 μm. Our new geometry is simple to manufacture and requires just one dry etch step to define the SWG array and one wet etch step to remove the SiO2 layer. This fabrication method enables the thickness of the air gap to be precisely controlled, which is important when operating at longer wavelengths (8-12 μm). Our design also ensures that the waveguide core can be surrounded by an analyte, thereby increasing the sensitivity of potential sensors.
Figure 2: SEM image of a suspended Ge waveguide with metamaterial lateral cladding.
We have fabricated a new batch of Si optical modulators operating at 2 μm and increased their data rate from 20 Gb/s, reported last year, to 25 Gb/s, another worldleading result. We have also significantly reduced the insertion loss of these modulators, paving the way for Si-based transmitters and transceivers in this extended wavelength range.
Wafer-scale manufacturing protocols for emerging 2D materials Challenge To achieve CMOS compatible, wafer scale processing of 2D materials for optoelectronics applications.
Progress Our research has focused on optimising the electrical properties of uniform, wafer scale, atomically thin molybdenum disulphide (MoS2) for use in developing nextgeneration transistor devices and large scale transition metal dichalcogenide (TMDC) monolayers for photonics applications.
Co-Investigator contact: Professor Dan Hewak dh@orc.soton.ac.uk
We have successfully employed an industry compatible, volume scalable atomic layer deposition technique to prepare uniform coatings of atomically thin precursor layers on a variety of substrates, including SiO2/Si, quartz and sapphire wafers up to eight inches in diameter. Using a dedicated annealing process, we were then able achieve MoS2 with the electrical properties required for transistor device applications. We have developed a Van der Waals Epitaxy method to fabricate large scale TMDCs, including MoS2 and WS2 monolayers and their heterostructures, which we have deposited on to CMOS compatible substrates, such as SiO2/Si, quartz and sapphire. We have also conformally deposited these monolayers on to microstructured silica fibres. Our international network of collaborators will further investigate the potential applications of these materials using the samples we have distributed to them under a Material Transfer Agreement. In parallel to developing these new manufacturing protocols for emerging 2D materials, we have developed a large scale transfer process to facilitate their integration with a wide range of flexible optoelectronics, silicon photonics, optical fibre and III-V devices.
40
41
| Large-Scale Manufacturing of Metamaterials and 2D Materials
Progress We are now routinely fabricating transistor devices for biosensing applications based on MoS2 in a process which optimizes electrical performance. In collaboration with industry partners, we have benchmarked the performance of MoS2 transistors for flexible optoelectronics applications and are currently focusing on further enhancing the technology. Our large scale WS2 monolayers have also shown promise for applications in radiation sensing. Working with a collaborator in Brazil, we have achieved a world-first demonstration of ferromagnetism in WS2 monolayers following their the exposure to a low dose of radiation.
Future plans We are collaborating with industry partners to upgrade the manufacturing process for MoS2 transistors to full wafer scale. Working with Sheffield, we plan to integrate these TMDC materials with III-V compatible technologies and explore commercial licensing opportunities.
| Integration
Developing integrated mid-infrared on-chip photonics Challenge To integrate semiconductor devices, such as lasers, LEDs and detectors, on a single chip for use in the functional manipulation of mid-infrared light. Our ultimate aim is to demonstrate a new generation of integrated, smart photonic chips, such as sensors, spectrometers, quantum processors and lab-on-a-chip diagnostic devices. To achieve this goal, we must first develop new manufacturing methods which enable photonic components, such as lasers, LEDs and detectors, to be integrated with passive semiconductor components, for example waveguides, modulators and interferometers on GaAs, silicon or silicon/Ge platforms.
Co-Investigator contact: Professor Jon Heffernanjon jon.heffernan@sheffield.ac.uk
Progress We have united the University of Southamptonâ&#x20AC;&#x2122;s expertise in mid-IR photonics with the University of Sheffieldâ&#x20AC;&#x2122;s experience in epitaxy and device fabrication to explore two approaches to the technological challenge of creating integrated mid-infrared on-chip photonic devices and systems. Together, we have made substantial advances in semiconductor processing technology. We have developed a flip-chip approach suitable for combining large scale Quantum Cascade Laser (QCL) structures, epitaxially-grown on indium phosphide substrates with silicon/germanium photonic chips. The process incorporated heat flow management in and around the lasers, removing a critical barrier to integrating the separate technologies. Using this technique, we have produced integrated QCLs with optimal on-chip optical efficiencies, emitting in the 5.6 Îźm waveband region required to detect gases such as ammonia.
42
43
| Integration
(a)
Figure 1: Schematic of an on-chip Fourier Transform Interferometer based on buried GaAs waveguides.
In a new area of research, we have been working to demonstrate an on-chip Fouriertransform infrared spectrometer for spectral analysis in the mid-IR region. The principle for this device is founded an on-chip Mach Zehnder interferometer with thermally tuneable waveguides (see Figure 1) and relies on gallium arsenide (GaAs) technology. We have made significant advances in epitaxial regrowth by metalorganic vapourphase epitaxy and have fabricated the on-chip FTIR device using a ‘buried waveguide’ method. Our process developments have focused on overcoming the challenges associated with waveguiding in the mid-IR region of ~4 μm. We have established the capability to produce the very thick (>5 μm) GaInP clad region needed for guiding the mid-IR target wavelength, ensuring the high optical and structural integrity of the cladding material by lattice-matching it to GaAs. Having produced the GaInP cladding to the required specification, we were then able to bury the waveguides inside; Figure 2a shows an SEM image of a successfully grown GaAs waveguide with GaInP overgrowth.
44
(b)
Samples of our high quality regrowth, developed in Sheffield, have now been passed to the team at Southampton for optical guiding measurements; Figure 2b shows a camera image of our GaAs waveguide successfully guiding mid-IR light. Whilst we are continuing to develop and measure optical losses in the waveguides, they have been shown to be of high optical quality in our initial tests; for example, the waveguides depicted in Figure 2b show no signs of scattering or optical leakage. We have also completed a mask for use in fabricating the full FTIR spectrometer over the coming months. Furthermore, we are currently exploring a second approach to producing an integrated on-chip sensor, based on the fully homogenous integration of different photonic components onto a single III-V semiconductor substrate.
Figure 2: (a) Electron microscope image of a GaAs waveguide for mid-IR optical guiding. The square GaAs waveguide has been grown on 5 μ m of GaInP, etched into a 2.5 μ m wide ridge and then buried in 4.3 μ m of GaInP. The top GaInP layered required significant development of epitaxial regrowth technology to ensure smooth conformal coating required for low optical losses. (b) Top view of optical guiding of mid-IR light. There is no sign of any scattering along the length of the waveguide indicating good optical quality of the buried GaAs waveguide.
45
| The team
| Industry partners
Deputy Director and Manager: Professor Gilberto Brambilla, University of Southampton
Business Development Manager: Tom Carr, University of Southampton
Co-Investigator: Professor Martin Charlton, University of Southampton
Coordinator: Ruth Churchill, University of Southampton
Deputy Director: Professor Jon Heffernan, University of Sheffield
Co-Investigator: Professor Dan Hewak, University of Southampton
Public Engagement Leader: Pearl John, University of Southampton
Industrial Liaison Manager: Dr John Lincoln
Co-Investigator: Professor Goran Mashanovich, University of Southampton
Michelle Mitchell, Research and Relationship PR Officer
Co-Investigator: Dr Senthil Murugan Ganapathy, University of Southampton
Principle Investigator and Director: Professor Sir David Payne, University of Southampton
Co-Investigator: Professor Francesco Poletti, University of Southampton
Co-Investigator: Professor Graham Reed, University of Southampton
Co-Investigator: Professor David Richardson, University of Southampton
With special thanks to:
Co-Investigator: Professor Jayanta Sahu, University of Southampton
46
Yvette Melia, Research and Relationship PR Officer
Co-Investigator: Professor Michalis Zervas, University of Southampton
Co-Investigator: Professor Nikolay Zheludev, University of Southampton
arbon Trust, Huawei, Honeywell Aerospace, II-VI Photonics, IQE, IS Instruments, Lightpoint Medical, Lumenisity, Merck, C Microsoft, NorthLab Photonics, Northrop Grumman, Oclaro, Phoenix Photonics, PragmatIC Printing, QinetiQ, Rockley Photonics, Seagate Ireland, Sestosensor, SPI Lasers, Breakthrough Prize, Defence Science and Technology Laboratory (DSTL), European Office of Aerospace Research & Development, Engineering and Physical Sciences Research Council (EPSRC), European Commission, Horizon 2020, Innovate UK, Royal Academy of Engineering, Royal Society
If youâ&#x20AC;&#x2122;d like to know more about the Future Photonics Hub, or find out how we can work together, please contact us: +44 (0)23 8059 9536 contact@photonicshubuk.org www.photonicshubuk.org Follow us @PhotonicsHub
