Highlights from a packed PIC International show in Brussels, charting progress in DWDM systems, a wishlist for future optical modules, and more...
Features Editor, PIC International Magazine
Welcome to issue #5 of PIC International magazine. We’re delighted to bring you more industry insight on the hot topic of photonic integration, including innovation in DWDM systems, uniting lasers and detectors in GaN, plus a look at key collaborations in chip design and simulation.
In our cover story, Harald Bock - VP of Network & Technology Strategy at Coriant - highlights how silicon photonics and other integration approaches are translating into increased equipment density and lower power consumption. And we catch up with Sven Otte - CEO of Sicoya - to find out why we need PICs to deliver high-speed transceivers in the large quantities that customers are calling for.
Eric Loos, with 20 years of experience alternating between network engineering, architecture design and operational roles, share’s his wishlist for driving out costs from tomorrow’s internet.
Stepping into the lab courtesy of our sister title Compound Semiconductor we take a look at progress in integrating multiple functions on the same chip - work that paves the way for advancing a range of applications, including smart lighting, displays and visible light communication.
In our show report, we bring you a flavour of PIC International 2017 and further capture the energy of the event in a photo feature celebrating the PIC Awards, which reveals all of this year’s winners across six categories - as voted for by the industry.
It takes talent to deliver today’s optical chips, and Jonathan Marks of Photon Delta travels to travels to Enschede in the Netherlands to see what’s inspiring tomorrow’s engineers.
Also, if you haven’t done so already, do check out the updated speaker profiles at PIC International to catch up on the latest additions to our sister conference. The two-day show offers the perfect venue for discovering the latest industry breakthroughs and finding key contacts. I’ll be at the event both days and look forward to meeting you there.
Plus, we catch up with PhoeniX Software to find out more about their PIC Award’s win and to get their thoughts on the road ahead to support the future needs of the device community.
Dates for your diary
PIC International 2018 will take place 10-11 April at the Sheraton Airport Hotel, Brussels. Secure your place by registering your interest today - visit https://picinternational.net/register.
Enjoy the issue!
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Optical functions that represent the building blocks of modern networks can now be squeezed into highly compact pluggable units. Harald Bock, VP of Network and Technology Strategy at Coriant, looks at how silicon photonics and other integration approaches translate into increased equipment density and lower power consumption.
Existing data and cloud networks, the distribution of video content, and new applications such as IoT, Smart Home, and 5G mobile are all driving the escalating demand for networking capacity. In fact, the total energy consumption of communications devices and networks has been increasing faster than the world energy consumption overall1 and already has a share higher than 6% of energy consumed today. With this growth, reducing the costs associated with increasing power consumption and footprint have become a major objective for network operators as well as equipment manufacturers. Key technologies supporting this need to evolve networks more efficiently are electronic and photonic integration with silicon photonics (SiP) in particular driving innovation in this field.
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In this article, we are going to look at different approaches that enable more efficient optical data transmission networks as well as explore a few examples of how those technologies translate into increased equipment density and lower power consumption. We do not intend to reproduce the chip-level discussion between different approaches that is well covered in books2 or research papers3. In other words, we will perform a reality check on photonic and electronically integrated components from a DWDM systems perspective and provide a future outlook for this technology.
Advancing optical systems
Innovation in small form factor and low power consumption almost to this day has always been based on a combination of several technologies and elements including electronic integration, photonic integration, and miniaturization. A wide range of technologies is available that helps with the integration of functions required to reduce the size and power consumption of a full optical system. And a number of different elements are often used simultaneously.
Photonic integration was, and still is, a mix of different approaches. Different material systems are used for single chip integration including Indium Phosphide (InP), silica on silicon, polymers, etc. Those materials differentiate through their optical properties, allow for different functional elements, and require different packaging technologies. This means that the different materials are each used in their own sweet spot applications. InP is particularly well established for optical interface applications4, whereas Silicon or CMOS Photonics has recently started to enter the market as an important alternative.
In most use cases, hybrid photonic integration becomes important as functionalities implemented in separate blocks, sometimes using a variety of technologies, need to be combined into a single entity within a package. Examples are die-to-die integration of lasers or semiconductor optical amplifiers with a SiP die or monolithic integration of different material systems during wafer processing.
To complement the benefits of photonic integration, micro-optics and miniaturization are used to further increase density while reducing the number of separately packaged entities required. Progress through miniaturization strongly relies on innovation in alignment and manufacturing processes.
On the system level of an optical transmission system, electronic integration has been the major tool to reduce size and power consumption for a long time. This has been particularly important with the introduction of coherent transmission systems that need digital processing in their transceivers. Communications chipsets are using the progress in semiconductor processing with feature sizes of 16 nm today and a roadmap to 11 and even 7 nm technology. Today, digital processing chipsets and framing devices usually transmit 400G per chipset with newer generations in development that will provide more than 1T of bidirectional throughput in a single chip. In parallel, the capacity of switching chipsets is increasing and matches this new level of transmission speed. Today, packet switching chipsets provide up to 64 x 100GE or 6.4 Tbps capacity.
In recent developments, the integration of electronics and photonics into a single device, e.g., the integration of analog drive circuitry into an optical chipset or the hybrid integration of an optical interface technology with a digital processing chip into a single package, will drive the capacity and density of functions within a single package to entirely new levels.
Now what does photonic integration offer on the level of an optical network transmission system?
We know that the main benefit of any kind of photonic as well as electronic integration is a reduction in the power and size of systems. But it is always useful to look back to understand just how fundamental those improvements are. Figure 1 illustrates the increase in equipment density achieved from the previous days of 10G/wavelength WDM systems to the current >100G/channel DWDM networks based on coherent transmission.
Figure 1: The timeline for the optical network industry to reduce size and power consumption on a system level
It was around the turn of the millennium when optical network nodes consisted of racks of equipment. DWDM systems alone filled several racks, while switching equipment filled additional ones. Individual optical functions required cards in several slots – and often full shelves were used for ROADMs or for a single add/drop function.
Around 2006, a new generation of DWDM systems reduced power consumption and size substantially. With these advances, optical functions were integrated on cards. For example, full add/drop functionality was available on a single card or a full network node was contained in a single shelf. And technology advances did not stop there. Looking at where we are today, optical functions are not on cards but in pluggables and network nodes are located in a flatpack or pizza-box format with up to 3.2 Terabits of bidirectional interface capacity in 1RU. This represents impressive progress with very compelling economic benefits that are playing out in key applications such as Data Center Interconnect (DCI).
This rather impressive track record of integrating optical functions from shelves into cards and still further into optical pluggables, as well as the increase of line rate per slot from 10G to several times 100G is enabled by a combination of technologies and approaches such as photonic and electronic integration as well as miniaturization. Before looking at the next technology steps that will bring us to >1 Tbps per slot, let us explore some of the photonic chip level integration technologies that have been instrumental in getting us to our current level of integration.
PLCs in optical layer integration
Some optical modules do not require the integration of active optics, i.e., laser sources or waveguide optical amplification. These modules can be manufactured using a choice of very low insertion loss materials. For example, planar lightwave circuits (PLCs) have been used for a long time to create arrayed waveguide gratings (AWGs) that act as optical multiplexers and demultiplexers. Additional functionalities were integrated with those AWGs, such as arrays of variable optical attenuators that allow for the setting of optical power levels in the system or even some more complex structures, resulting in the first optical networking functionalities on a single chip.
Figure 2 shows two examples that helped reduce node size from full racks to a single shelf in the 2005 to 2010 timeframe:
Figure 2a – Integration of WSS and add/drop filters into a single card carrying a single PLC chip – size is based on the number of connectors
Figure 2b – Integration of 40 channel mux with 40 VOAs reduces footprint from 7 to 2 slots
From 10G to 400G
The integration of optical interface technology, particularly for DWDM transmission across wide area networks, targets increasing throughput. Here as well, the progress achieved through electronic and photonic integration is best demonstrated by taking a look at card faceplates (Figure 3) from 10G interface cards in 2005 to the 400G line cards available today.
Figure 3: Faceplates of DWDM line cards evolving from 10 Gbps in 2005 to 400 Gbps today
The transition to coherent 100 Gbps and 400 Gbps transmission with digital signal processing involves a significant level of electronic integration. When the integration of active components such as lasers, amplifier, and electro-optical modulators is required, InP is the key material system used. A significant part of transceiver modules rely on InP today, and InP as a material system offers substantial benefits, particularly around optical performance/reach, but there are a number of drawbacks versus other materials. For instance, InP requires special fabrication and is sensitive to environmental conditions including humidity. Nevertheless, analysts expect InP to continue to be the key material system for photonic integration into the future5.
The rise of silicon photonics
We have seen that multiple approaches help to reduce size and power consumption per capacity in transmission systems. The promise of silicon photonics technology has been discussed for a long time in this context. Why is there so much interest in silicon photonics as a technology right now?
As highlighted in a research report by LightCounting in 20175, new technologies often start to gain pragmatic traction only after overzealous industry expectations (i.e., hype) begin to fade.
Figure 4: Industry hype cycle (LightCounting)
Following the peak of hype around SiP (approximately 20125), reality kicked in, and in the years since, tough questions have been asked about the promises and the reality of SiP.
So where does that leave us today? Although the high-level picture has remained unchanged, in recent years, there are a number of optical components based on SiP that have been introduced into the market. This trend continues today, with most work right now focused on integration of Tx/Rx in pluggable interface modules.
While the major commercial ramp is only beginning, progress in the industry has continued to chart a viable course across the proverbial chasm of technology adoption since the SiP hype cycle. A large part of this progress is due to the development efforts and funding focused on the application of SiP in other (non-optical networking) industries, particularly in the IT and µprocessor industries. IBM, Intel, and others have helped drive innovation in chip-to-chip optical interconnect technologies, which have positive implications for SiP advances in the optical networking arena.
By now, SiP technology has become the basis of market success for companies such as Acacia Communications or Skorpios Technologies as well as new players entering this market such as Elenion Technologies, a company that emerged from stealth mode earlier this year and has introduced next-generation photonic integrated circuit technologies and solutions for a broad range of datacom and telecom applications.
Now what are the next key steps in integration that will translate into significant benefits on a system level? Here, we should look at two key areas: optical interface and optical layer technology.
Optical interfaces are the main focus of innovation as they represent the major part of the system level space and power requirements. Combining the electronic integration of 400 Gbps into a single digital processing chipset with silicon photonics integration into CFP2-ACO pluggable interfaces provides the highest density and lowest power optical DWDM technology available today (Figure 5).
Figure 5: Coriant Groove™ G30 DCI Platform with 3.2 Tbps per rack unit of throughput at 450 W / 100 Gbps of power consumption
The industry is working to increase the efficiency of optical interfaces further through the following methods:
The optical transmission layer follows this evolution by optimizing to new line rates. Also, a transition to truly open line systems removes vendor lock-in and speeds up the introduction of new optical interface technologies.
Figure 6: Coriant Groove™ G30 Open Line System Configuration
Integration of the optical system layer has reached a level where a full line system terminal fits into a 1RU pizza box including mux/demux and optical amplification as well as dispersion compensation if required (Figure 6). We can expect that additional optical layer functionality will be integrated into the same footprint.
Overall, the good news for optical networks is that progress in electronic and photonic integration enables a continuous evolution towards ever more efficient and scalable networking equipment. Silicon photonics integration has started to play an important role in this context and will become an increasingly important alternative to other technologies. This innovation evolution coincides with the long term vision of full custom SiP optical ASICs enabled by the fabless technology model. With increasing investments into SiP technology, we can expect a significant contribution from this disruptive technology in the years to come.
 Sofie Lambert and Mario Pickavet, "Can the Internet Be Greener?" Point of View, Proceedings of the IEEE, vol. 105, no. 2 (February 2017): 179-182.
 Lukas Chrostowski and Michael Hochberg, Silicon Photonics Design (Cambridge University Press, 2015).
 Christopher R. Doerr, "Silicon Photonics integration in telecommunications," Frontiers in Physics, (August 5, 2015), doi: 10.3389/fphy.2015.00037.
 Meint Smit et al, "An introduction to InP-based generic integration technology," Semiconductor Science & Technology, vol. 29, no. 8 (2014): 41.
 "Integrated Optical Devices, Is Silicon Photonics a Disruptive Technology?" LightCounting, January 2017.
 "Coriant Announces Silicon Photonics-Powered Short Reach CFP2-ACO Pluggable for Groove Network Disaggregation Platform," Coriant press release, March 9, 2017. http://www.coriant.com/company/press-releases/Coriant-Announces-Short-Reach-Pluggable.asp
 "Acacia Communications Samples Industry's First Coherent CFP2-DCO," Acacia Communications press release, November 7, 2016. http://ir.acacia-inc.com/phoenix.zhtml?c=254242&p=irol-newsArticle&ID=2220222
Harald Bock is VP of Network & Technology Strategy at Coriant and has more than 20 years of experience in optical and data networking. Before joining Coriant, he was R&D project leader DWDM at Nokia Siemens Networks and has held positions at Marconi and Ericsson.
In 2017, Sicoya -- a Germany-based developer of highly-integrated silicon photonics and spin-out of TU Berlin -- launched its first products into the data centre market. Sven Otte, the firm’s CEO, explains why we need Photonic Integrated Circuits (PICs) to deliver high-speed transceivers in the large quantities that customers are calling for. Interview by James Tyrrell.
Q1 - What do you see as the big benefits of PICs and how is Sicoya applying this technology to deliver attractive solutions to its customers?
We are now going into an era in which we need ultra-high speed transceivers. Huge demand is being driven by both machine-to-machine communication and mobile communication, but applying discrete manufacturing approaches to 100x higher volumes is impractical - the cost doesn’t scale with volume any further and quality can be affected. Photonic integrated circuit (PIC) technology addresses these challenges - the volume constraints quality and cost.
Co-integration solution: Sicoya’s transceiver chips feature analog electronics and optics fabricated, using SiGe-BiCMOS process technology.
There is some debate in the industry about which PIC technology to use – for example, are silicon (Si) or indium phosphide (InP) PICs better suited for future solutions? But we see different PIC platforms becoming commercially available and that’s good because each technology addresses a specific problem. Silicon is the better material system from a manufacturing point of view. It is, practically speaking, available in abundance and offers outstanding material properties when, for example, looking at the number of crystal dislocations or the surface quality. As a result, the cost of Si is 10x lower than InP. In addition epitaxial growth and lithography processes in Si outperform their InP counterparts. From here we can easily see why processing 300mm Si wafers with very high yields is achievable while the size of InP wafers is limited to 80mm and yields are lower.
Silicon devices, both the electrical and the photonic components, tend to be much smaller because of the lithography processes and the material properties - for example, we can build very high-speed modulators that are less than 100 micrometers long in Si while in InP the same modulator is around a centimetre in length. Overall, this leads to a situation where all building blocks that can be achieved in Si will be made using Si eventually. Obviously, Si is an indirect semiconductor and hence cannot generate photons. So, consequently, we will continue to use InP, but only where needed - for example, to create the laser.
However, even lasers can be broken down into subparts such as the gain medium and the grating. Gratings can be made in silicon and for the gain medium a thickness of a few hundred nanometres is sufficient, which can be integrated in a CMOS process. Indium phosphide may therefore become a complementary material in an overall Si wafer manufacturing flow just like germanium is in today’s BiCMOS processes, for example. This however is in the future. Today InP and silicon photonics co-exist.
At Sicoya, we bring the integration approach to the boil and we are combining entire transceivers into a single Si chip, which we call ‘Module-in-Chip’ (MiC) technology. All electrical transceiver functions such as clock and data recovery, control loops, amplifiers, modulator drivers and all optical functions including modulators, multiplexers and photodetectors are integrated in one small chip.
We benefit from the manufacturing technology of our commercial BiCMOS foundry and achieve the same quality and cost data compared with conventional BiCMOS processes – that is a promise that has been made in the past already and is now a reality. Additionally, we have developed a 3D packaging concept which allows us to put our MiC engines very much like standard semiconductor packages.
Another element of our know-how are the devices itself. In semiconductors one can differentiate by the way transistors and resistors are put together inside the chip - that is, by the circuit design. Photonic circuits are in comparison much simpler and differentiation is only possible on device level. At Sicoya it took us more than 10 years to develop and patent the devices that we are now using in our products.
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Q2 - Can you talk about the journey from idea to device - what do you see as the challenges in making the most out of PIC-based platforms?
Our journey began 2006 when we started to develop the basic process and device technology. This was research at its best and we are grateful for all the support which was coming from national and EU resources. Now we are entering the commercial stage, and development cycles for new products need to come down from 10 years to 1-2 years. This represents a challenge from various aspects.
To highlight one area, PIC platforms generally tend to have a research background with outstanding technology capabilities, but at the same time it’s important to also have the internal processes to support agreements on delivery, price and quality details. Assume, one develops a product on a PIC platform, which cannot support a commercial business. It would mean that the design must be transferred to another foundry, which typically isn’t possible over a short time frame. We are in a fortunate position to have an EPIC (Electronic-Photonic-Integrated Circuit) platform which supports both research and high-volume commercial business and I expect that more platforms follow this example in future. It’s worth adding that this example is not limited to PIC foundry platforms - it applies to packaging services as well.
Q3 - 2017 is sounding like a very exciting year for the company with the launch of your first chips for use in data centres. Looking ahead, what's your vision for future internet services? Where could PIC technology take us?
Yes, indeed – 2017 is a super exciting year for Sicoya and we are getting great feedback across the globe. Our initial 100Gb/s products are just the beginning as we keep pushing the possibilities and features of the EPIC technology. It’s an amazing start and you can expect much more to come in the next 1-2 years.
If we look at industry trends, data rates are moving from 100Gb/s to 400Gb/s and we can achieve this at lower cost and with better performance. We are also actively driving a change in the way standards are written. When you have all optical and all electrical signals available in one chip, this opens up the possibility for new types of products. As photonic AISICs become available in a semiconductor package why not eliminate a few switch hierarchies in a data centre? I am not talking about a one-by-one replacement of copper with optics. Rather, it’s a change in the architecture of data centre in which servers and storage devices are connected to the network optically without copper and switches in between.
We also see interesting things happening in the IoT and sensor area where PICs can be an enabling technology for new products. The future for (E)PICs is bright and we are glad to be part of it.
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Eric Loos, with 20 years of experience alternating between network engineering, architecture design and operational roles, share his perspective on being stuck between a rock and a hard place at the twilight zone between analogue and digital. And draws up a wishlist for driving out costs from tomorrow’s internet.
It was my pleasure to attend the PIC International 2017 conference held in Brussels recently as the event was a great reminder of the incredible technology that contributes to leaps of advancement in service provider oriented products. In turn, telecoms operators will configure those products into an end-to-end service based on various architectural choices, customized for the geography and the particular challenges in their market. By the time in the product & service lifecycle that someone actually sets out to use it, several layers of abstraction have generally significantly filtered the information.
From a business point of view, there might be capabilities that are extremely valuable to me, but that remain undetected since equipment vendors have not seen a large enough market for them and very likely those same business requirements may not filter down to companies creating the actual integrated photonics.
In this article, I will dive into the world view of one company, grappled in a battle for business against a dozen or so other service providers in an extremely competitive Western European wavelength services market.
Accommodating traffic growth
The internet is ubiquitous. Over the past two decades the Northern hemisphere has evolved to the point where most people over the age of twelve are constantly tethered to data centres worldwide, providing them with the next nudge, communication or music track to listen to. Pocket-sized devices have evolved from basic phones to the latest generation of smartphones capable of providing high-definition video and sound, as well as considerable computing resources. And the appeal of smart TV’s, laptops and smartphones is soon limited without a constant connection to digitized, internet-hosted content.
Last year, 70% of all internet content consumed by North American internet users, measured in terms of network bandwidth, was served out of only 10 global internet connected networks. It is no surprise to see names like Amazon, Facebook, Microsoft, Google or Netflix in this list. These household names have become synonymous to the internet for many consumers.
This has transformed the role of internet service providers (ISP), eroding their value added services portfolio to the point that the value creation of most ISP’s is primarily basic connectivity. The move of traditional communications like voice and SMS to Over The Top (OTT) solutions and similar trends in providing content via online services, have further accelerated the reduction of triple and quadruple-play offerings to a dual-play bundle based on delivering data over fixed and mobile networks.
In parallel, consumers expect better and cheaper services. In this equation with flat or declining revenues, service providers must find a way to accommodate the 30% year-over-year traffic growth knowing that at most 10-15% of cost-savings can come from a reduction in equipment pricing. As a result, other initiatives inside the internet service providers such as automation, evolving architectures, economies of scale and self-service portals, must further allow the service providers to save at least another 15% in costs.
Considering network infrastructure
There are several dimensions to the network infrastructure cost, if it is considered end-to-end. Equipment vendors have focused largely on increasing the throughput through the existing fibre plant as a way to increase the efficiency of the network. A key consideration in long-haul networks is the reach, both in terms of reach between amplification and the reach before regeneration becomes required.
Especially the need for regeneration drives up the cost significantly because it is a per service requirement, unlike the amplification which applies to all services on the same fibre.
Supporting a granular footprint with a ubiquitous service feature parity is another compounding challenge because service providers buying such long haul services have come to expect that features such as protection and restoration are coming at virtually no extra cost. It is commonplace that even for services routed over a single 2.000km fibre, repair targets are set to 30 minutes - a target impossible to achieve in case of a fibre cut. The simplicity of the network is also a requirement to keep the costs of automating service delivery down and key in enabling the integration of IP and Optical networks. This integration is achieved by deploying Software Defined Network technologies, which offer centralized control over the traffic flows in data networks. This is seen as one of the approaches to drive out costs through the elimination of independent layers of redundancy and the introduction of a vertically integrated end-to-end multi-layer redundancy scheme.
Making the correct trade-off presents an ever moving target, forcing long-haul service providers to make an uneasy compromise between the ubiquity and simplicity of a homogenous network platform architecture and the individually cost-optimized, end-to-end solutions across minimalistic common open line system infrastructure.
Most pricing models today are based on accounting for fixed costs of the underlying platform infrastructure such fibre plant, rack space, power, muxes and equipment chassis to which unitary costs for transponders, optics and patching are added. The shared cost portion taken into account to price each individual service is usually based on longer term network utilization forecast.
So where do we go from here?
Driving out costs from the system can come in a variety of ways, most of which are not necessarily feasible today, but I’d like to highlight the following for consideration -
Eric Loos joined BICS in 2007, holding positions as architect of the Carrier Ethernet Service Network and manager of the expert team in the operations department before taking up a role as Senior Product Manager Capacity & IP at the end of 2011. He has over 20 years of experience in the Service Provider segment, alternating between network engineering, architecture design and operational roles. Familiar with all stages of a network lifecycle, Eric has a unique perspective on the challenges faced by service providers and carriers. In addition, he is a board member of the Amsterdam Internet Exchange and a contributor to the PeeringDB project.
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Packed speaker sessions, industry awards debut, and a lively exhibit. James Tyrrell shares his notes on this year’s conference and highlights important dates for your diary.
Photonic integration was top of the agenda as industry experts gathered in Brussels in early-March for a busy two-days of technical talks, exhibits and networking. PIC International’s popular format offers a unique snapshot of the industry, diving deep into the technology, design flow and production, as well as delivering a broad perspective on application opportunities from data centres to diagnostics.
Here are just a few of the highlights, together with dates for your diary so that you can add next year’s show to your calendar.
Featuring all-new themes for 2017, PIC International’s technical track began by examining how PICs can support data centre growth. Keynote speaker Richard Pitwon of Seagate highlighted how today’s data landscape is fundamentally changing IT. Eight out of ten computing devices are phones and tablets, and it’s estimated that 70% of all data will be stored remotely by 2020. One of the key questions is - how far can optics penetrate into the system?
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The EU is pushing hard through a raft of PIC-based projects to take the technology to the next level, and firm’s such as Seagate are partnering in areas such as data centre network architecture. At the same time there’s scope for international standards to help accelerate the commercial adoption of integrated photonics.
Bert Offrein of IBM showcased scalable integration concepts aimed at driving down the cost of data centre photonics. Developers are working hard on this theme as features such as directly integrated light sources and smart approaches to assembly could bring about savings in the range 60% - 80%.
It’s no surprise to hear that exponential data growth represents a challenge for networks, but Intel’s Robert Blum added some important detail by flagging up the huge increase in machine-to-machine traffic. Internal data centre traffic can be fives times higher than global internet traffic, which is why unconstrained optical connectivity has become a major goal.
A packed conference room, including delegates from all the leading companies involved in the PIC industry.
Production progressMonolithic integration paves the way for very low light loss between device elements, and progress in on-wafer testing is a key part of realizing optical systems on a chip at volume quantities. Graham Reed of Southampton University’s Optoelectronics Research Centre gave delegates a preview of solutions in the pipeline such as erasable grating couplers. And firm’s such as Kaiam, are helping to streamline optical alignment and bring about important cost-savings. Henk Bulthuis, team leader of optics design Europe, gave examples of how MEMS-assisted coupling is being deployed by the company at its production sites.
A packed exhibition hall, promoting networking and creating new business opportunities.
There was a strong design contingent at the conference with on-topic technical sessions led by Cadence Design Systems, VPIphotonics and PhoeniX Software, to give just a few examples. Speakers highlighted the ‘heavy lifting’ that today’s layout and simulation packages can perform for users, and tools for capturing fab data to accommodate process variations into the process.
“PIC technology has reached the tipping point,” Twan Korthorst told the session audience. “Many companies are expanding their device teams and increasing the number of design starts.”
Data centres and telecoms networks are major drivers of PIC technology today, but the conference also makes room for emerging applications. At this year’s event, Liesbet Lagae of imec highlighted the opportunity for SiN biophotonic integrated circuits in the life sciences sector. Bio is big business, but in order for PICs to play a major role the community needs to figure out a mature supply chain. Lagae is a key member of the PIX4life co-ordinating team, which aims to provide a bridge to manufacturing through its open-access manufacturing platform for photonic integrated circuits.
Space is another exciting prospect for PIC technology and Iain McKenzie of the European Space Agency presented a long list of potential uses for photonic chips onboard spacecraft. Key metrics are size, weight and power, which plays into the hand of lightweight, mechanically robust and energy-efficient PIC devices.
I filled a whole notebook with highlights from this year’s show, and this write-up is just a glimpse at the opportunities for major PIC platforms such as silicon photonics. The conference, which includes an exhibit held over both days, gives attendees the perfect chance to quiz providers of manufacturing equipment, find custom solutions and hear from end-users such as network providers to build a spec-sheet for future products.
Dates for your diary
PIC International 2018 will take place 10-11 April at the Sheraton Airport Hotel, Brussels. To make sure that you don’t miss out - register your interest today by visiting https://picinternational.net/register. We have numerous speaking and sponsoring/exhibiting opportunities available for PIC International 2018 - if you would like to find out more, please contact the Event Director, Sukhi Bhadal at:
firstname.lastname@example.org or +44 (0)24 76718970.
About the author
James Tyrrell is a freelance science and technology writer working with Angel Business Communications on PIC International magazine and its sister conference PIC International.
The photonics sector is fuelled by bright ideas and smart thinking. AIM’s academy program and other key organizations such as imec run popular training courses to update engineers on photonic integration, but can companies do more to bring skilled workers into the field? Jonathan Marks travels to Enschede in the Netherlands to visit two technology universities that have partnered with photonics firms to deliver industry-focused courses in optical chip design and manufacturing.
The established money-making machines at Amazon, Microsoft and Alphabet (parent company of Google) are very different from each other. But as the New York Times reported in April, their Q1 2017 earnings report revealed that cloud computing is becoming financially more important to all three of them.
Advertisement: PIC International Conference, 10th - 11th April 2018, Brussels, Belgium. The must attend event for the integrated photonics industry - www.picinternational.net.
Amazon, the leader in online retailing, said the $890 million in operating income from Amazon Web Services accounted for most of its overall profits. Microsoft, the No. 2 player in cloud computing is steadily making the transition to that business. The Azure cloud hosting business grew by 93 percent from the year-earlier quarter.
Alphabet has told analysts that the Google cloud platform is one of the company’s “fastest-growing businesses”. Although the parent company offered no details, Urs Hoelzle of Google revealed the extent of growth at this year’s Optical Fiber Communication Conference. In the last 10 years, Google's infrastructure has scaled by TWO orders of magnitude. 1 billion hours of YouTube video are watched every day - that means 10,000 hours a second.
But although things appear to be booming right now in the photonics sector, large international corporations are warning that change is needed. With 10X growth in the data centre market over the last 3 years, different approaches will be needed so that companies can make the most of this opportunity.
Positioning photonics as the smartest career move
In the run-up to the World Technology Mapping Forum in June, PhotonDelta has launched a wake-up call for academia. “If Europe is going to maintain its lead in photonics, then its academic institutions need to do much more to position photonics as a smart career path.” says Ewit Roos, MD of PhotonDelta. “Other industry sectors are already aware of the acute shortage of students with qualifications in high tech related subjects. Some, like artificial intelligence, robotics and automotive have benefited from public awareness through TV and social networks and movies on subjects like code-breaking. That’s more difficult with a key-enabling technology like photonics. But now is the time to make a clearer case for optics.”
“There are a growing number of study portals where students can compare courses and find the best universities and colleges. It's worrying that when you enter the word photonics or even nanotechnology into these new search engines, very little, often incomplete information comes back. We’re putting out a European-wide call to fix that.”
“At the same time, there is good news from the East of The Netherlands, where high-tech photonics companies have taken a different approach. They persuaded the University of Twente and Saxion University of Applied Sciences to build complementary courses to supply the Netherlands with the right kind of high-tech skills that are needed. We believe there is a need for more initiatives like this across Europe. And we’re always interested in what colleagues in other countries have built and how they get the word out. If you’re interested, get in touch by emailing - email@example.com."
What does it take to support the application of photonic integrated circuits? The PhoeniX Software team recaps the company’s origins and growth in optical design, highlights key collaborations, and shares its thoughts on the road ahead to support the future needs of the industry.
In March of this year, PhoeniX Software of Enschede, The Netherlands was selected to receive the Design and Packaging Award given at the PIC Awards 2017 ceremony held at the PIC International Conference in Brussels. This is a prestigious award with over 6000 votes cast from the PIC ecosystem worldwide. The award recognized PhoeniX Software’s role and positive impact that they have had in PIC design and packaging.
In fact, PhoeniX has been a major force in the development of the PIC ecosystem starting as far back as 1991 when several of its founders first started optical design work for Akzo Nobel for thermo-optic digital optical switches. By 1995 the group formed a commercial software entity known as BBV Software that offered photonic design automation products such as Thor, Selene, Prometheus and OympiOS. In 2000, BBV and another company, Twente MicroProducts were acquired and merged into Kymata where their photonics work moved from a research-centric focus to being product-centric, having to deal with the impact of mask quality and process variations on product performance and yield. During the tumultuous early years of the 2000’s, the group survived multiple acquisitions and management buyouts to finally emerge as PhoeniX Software in 2003.
During the first decade of the 2000’s PhoeniX Software worked on a new integrated photonics design platform known as OptoDesigner. Optodesigner is an object oriented, parametric, script-based design environment that enables designers to quickly create and assembly high quality layouts of their photonic designs. The tool suite enables designers to describe their photonic functions as a collection of interconnected technology-agnostic photonic building blocks. Those building blocks are automatically mapped onto a set of technology-specific building blocks (or built from scratch) based upon a targeted fabrication process. This process allows designers to be able to re-map the same design onto multiple different fabrication processes to find the best match for their specific application. The output of OptoDesigner is a set of mask layouts in GDSII format targeted to a specific foundry process that will be used to pattern the designer’s intent onto a medium of choice (e.g. photonic wafer or interposer, glass or polymer etc.). This mapping process is what is known as photonic synthesis. Photonic synthesis is a key technology in that it allows the designers to work at higher levels of abstraction, relieving them of having to spend weeks meticulously hand drawing photonic layouts.
Additionally, OptoDesigner also includes photonic simulation engines that can be used to design, characterize and optimize a photonic circuit. OptoDesigner simulations include advanced mode solving, thermo-optic and electro-optical effects, stress effects, and fast beam-propagation simulations, with or without reflections and coupling effects, that can be used in tightly integrated loops to automatically optimize circuits layouts to meet specific design constraints.
Building the PIC Ecosystem
The fledgling company struggled through the first decade of the 2000’s while the rest of the world went through multiple financial crisis and stagnation. The time however was well spent as it was through these years that the integrated photonic ecosystem started to take shape. PhoeniX Software took the lead in developing partnerships with multiple European R&D centers both for PIC manufacturing and PIC computer-aided design software. One of the key developments during this period was the introduction of the concept of standardized photonic building blocks and what became known as Photonic Process Design Kits (PDKs). These collaborative efforts eventually led to standardized design flows for integrated photonics with PhoeniX Software’s OptoDesigner tool being the physical design hub for many PICs designed since the resurrection of integrated photonics technology in the last couple of years. The combination of photonic synthesis and foundry PDKs was a marriage made in heaven and truly helped the photonic designers jump from laboratory experiments to production designs during this time.
Explosive Growth for PIC Design
Over the last five years (2012 – 2016) there has been explosive growth in integrated photonic design. During this time PhoeniX Software saw a clear shift of design activities from academia to commercial entities (see chart – figure 4). This was also reflected by PhoeniX Software’s own sales growth (25% CAGR over this period as shown in figure 5) with OptoDesigner for PIC design being the growth engine with a 49% CAGR during the same period with the lion’s share of that revenue coming from commercial entities. During this time PhoeniX Software led the industry by example, offering free industry education and support and expanding their reach outside of Europe with a direct sales channel in North America and with partners in Asia. One of the things that led to their winning of the PIC Award for Design and Packaging this year is PhoeniX Software’s overall philosophy that collaboration is key to both their customers’ and their own success. They understood early on that no one company owned all the capabilities required to successfully enable designers to field PICs and as such they went out of their way to lead the industry into a collaborative model. PhoeniX Software’s customers recognized these efforts and voiced their appreciation through their PIC Awards votes.
Figure 4 and 5
The Integration of Photonic & Electronic Design
There are many areas that must be addressed for integrated photonics to be a cost-effective alternative to electronics-only solutions. The first of these is to enable the integration of electronic and photonic systems. This implies an integration of design methodologies and CAD platforms for both worlds.
Again, PhoeniX Software is making great strides as an early photonic collaborator with the Electronic Design Automation (EDA) world. In addition to collaborations with Photonics Design Automation tool providers like VPIphotonics, Lumerical Solutions, and Photon Design, PhoeniX Software has announced partnerships with the “big-3” EDA companies, Cadence Design Systems, Synopsys and Mentor Graphics (now a Siemens company). PhoeniX Software has introduced integrated electronic-photonic design flows in collaboration with each of the three big EDA players enabling true electronic and photonic co-design.
An example of this collaboration can be seen in the work that PhoeniX Software has been doing with Cadence Design Systems as shown in figure 6. Cadence holds a leadership position in the EDA market with their Virtuoso custom design tool suite. Cadence and other EDA companies have long espoused the use of top-down schematic-driven-layout (SDL) flows for analog, custom and mixed signal designs. The PhoeniX-Cadence collaboration builds on the strengths of both tool suites enabling the integration of both electronics and photonics within the same design system. Cadence has augmented their CAD framework to include both electronic and photonic capabilities by partnering with both PhoeniX Software and Lumerical Solutions. Cadence supplies the tools for designing the electro-optical system including schematic capture, electrical spice simulation and a SDL-based layout flow complete with correct-by-construction layout capabilities with cross checking and cross probing between the schematic and layout worlds. PhoeniX supplies the native curvilinear shape engine used by Virtuoso to create curvilinear photonic waveguides and photonic modules while Lumerical Solutions provides a circuit level simulation capability for simulation of the photonic portions of the system.
PhoeniX Software is also looking to contribute in other areas that must be addressed to enable cost-effective photonic designs including design-for-manufacturing and design-for-test. It is PhoeniX Software’s desire to leverage from over four decades of electronic design automation learning in these areas to more rapidly bring these solutions to PIC design. And as before, they plan to collaborate with partners to bring these solutions to bear for designers. They already have a good start on the manufacturing front given their deep back ground in fab management software used for managing manufacturing processes and improving yields. They are also collaborating with Mentor Graphics’ Calibre team as shown in figure 7. PhoeniX and Mentor are collaborating in the areas of design-for-manufacturing by advancing the use of equation-based design rule checking for curvilinear photonic designs and design implementation methods for lithography-friendly photonic designs.
Next Generation PIC Design Methodologies
Added to this integration efforts between electronic and photonic design solutions is a new R&D activity to better enable photonic systems-in-a-package design. This will be the first integration method for photonic system designs where multiple electronic and photonic dice will be connected through die stacking and electronic-photonic interposers all within a single package as shown in figure 8.
PhoeniX Software has also embarked on another set of ideas to help PIC system designer productivity. As already mentioned, PhoeniX enables what they call photonic synthesis, whereby they designers can capture designs using technology-agnostic building blocks and then automatically synthesize the layout for those blocks using foundry-specific design rules and GDS layers. PhoeniX is now moving this up another level of abstraction. This is very much like what happened in digital design with the advent of logic synthesis in the early 1990s. PhoeniX Software has started with a toolbox for synthesizing photonic filter designs and is now working on expanding this concept into other photonic domains. If they get this right it has the potential to make photonic design take off like digital electronic design did in the 1990’s.
When and if that happens, you can expect several more awards being put in the PhoeniX Software trophy case.
More information – http://www.phoenixbv.com/index.php
Making its debut this year and voted for by the photonics industry, the PIC Awards programme was a big hit at the 2017 show - celebrating advances in optical chip design, manufacture, assembly and characterisation. Trophies were also presented to recognise key technology pushing integration to the next level and a lifetime achievement benefiting today’s PICs. Images from the event tell the story.
Applause and cheering filled the venue as the results of PIC International’s awards programme -- a new feature of the 2017 conference -- were announced. Voted for by the photonics community, thousands participated online to highlight industry achievements across six categories and winners faced tough competition for the top spot.
Clutching their PIC 2017 Awards it was all smiles from the winners, which included Kaiam - a firm advancing silicon photonics integration to address data centre demands.
James Regan, CEO of EFFECT photonics, keeps a firm grip on the trophy. Founded in 2010, EFFECT has been busy commercializing its optical system-on-chip technology for a range of applications, including data centre interconnects and metro networks.
It takes years of dedication to deliver the tools, services and equipment that help developers overcome the many complex challenges involved in producing high-performance PICs. During the ceremony, it was clear that award winners such as PhoeniX Software appreciated the recognition shown by community.
The six award winners (joined by EPIC’s Jose Pozo, who read out the nominations, and PIC conference chair Michael Lebby) on stage. From left to right, trophies were presented to Oclaro (Device Characterization), EFFECT Photonics (Advances in Integration), Meint Smit (Lifetime Achievement Award), SMART Photonics (Advances in Manufacturing), Kaiam Corporation (PIC Platforms) and PhoeniX Software (Design & Packaging).
The PIC Award’s programme will return in 2018, recognizing key achievements in advancing photonic integrated circuits. Make sure to look out for the call for nominations later in the year, and don’t forget that you can join in the celebrations by attending next year’s PIC International conference, which takes place 10-11 April, 2018 at the Sheraton Airport Hotel, Brussels.
Integrating multiple functions on the same chip paves the way for advancing a range of applications, including smart lighting, displays and visible light communication. PIC International’s sister title -- Compound Semiconductor magazine -- reports on a collaboration between KAUST, UCSB and KACST that’s making headway by bringing together a III–nitride waveguide photodetector with a laser diode emitting at 405 nm.
A collaboration between researchers in the US and Saudi Arabia has integrated a GaN laser and photodetector on the same chip, to create a device that offers optical power monitoring and on-chip communication.
The team believes that their device is the first to operate in the visible spectrum and deliver photonic integration via the use of the same InGaN/GaN quantum-well active region.
“Such a device is important for achieving a feedback loop to enable constant luminous lighting and realising high date rate, visible light communication systems – a step towards high-quality, smart lighting,” argues corresponding author Boon Ooi from King Abdullah University of Science and Technology.
One of the merits of the work is that it avoids the strong internal electric field on the c-plane, which causes a large separation between the absorption and emission peaks. The approach of Ooi’s group, working with researchers at the University of California, Santa Barbara, and King Abdulaziz City for Science and Technology, is to fabricate their photonic chip on the semi-polar plane of GaN.
Their chip features a 505 mm-long, 405 nm laser. Near its rear facet, separated by 5 mm, is a 90 mm long waveguide photodiode. Between the laser and photodiode is an isolation trench, formed by focused ion beam milling. This allows the two devices to operate independently, thanks to an isolation resistance of about 1 MW.
Measurements from the front facet of the laser, which is operated continuously, reveal a threshold current of 130 mA and a slope efficiency of 0.4 W/A. This is in good agreement with measurements of the waveguide photodiode at zero bias, which show a significant increase in photocurrent when the laser diode’s current is increased to 130 mA. At higher drive currents, lasing kicks in, and there is a significant increase in the photocurrent in the waveguide photodiode. This behaviour shows that the waveguide photodiode can be used for on-chip power monitoring.
Biasing the photodiode leads to enhanced optical responsivity. When driving the laser with 5 ms pulses at a 10 percent duty cycle to minimise heating, an increase in the bias from 0 V to 10 V leads to an increase in responsivity – the ratio of the photocurrent to the incident optical power – from 0.0018 A/W to 0.051 A/W. According to the team, this figure of merit is far higher than that for equivalent photodiodes on the c-plane, which have a responsivity of 0.001 A/W to 0.01 A/W.
Frequency measurements on the waveguide photodiode indicate a 3 dB bandwidth of 230 MHz. This is vastly superior to GaN Schottky barrier photodiodes and p-i-n photodiodes, which have figures of 5.4 MHz and 10-20 MHz. Ooi attributes the far higher frequency of their waveguide photodiodes their small size, stemming from the narrow ridge design, and the higher responsivity in the semi-polar plane. The higher speed is claimed to showcase the potential of the chip as an integrated receiver for on-chip communication and visible light communication.
Even higher levels of performance should be possible. According to Ooi, the DC and high frequency photoresponse characteristics of the waveguide photodiode could be improved by optimising the design, including the form factor and the facet angle. “By reducing the junction capacitance to about 5 pF, a 3-dB bandwidth of more than 500 MHz is expected.” Meanwhile, the efficiency of the laser could be increased by optimising the facet and turning to high-quality high-reflection coatings.
Plans for the future include the development of a multiple-section integration technology. This could enable complex monolithic on-chip integration of III-N light emitters and receivers for smart lighting, displays, and visible light communication.
Adding more functionalities could lead to photonic integrated circuits for optical switching, clocking and optical interconnects.Integrating a GaN laser and waveguide photodetector could aid smart lighting, by allowing the monitoring of optical power.
B. Ooi et. al. Appl. Phys. Express 10
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