Integrated Photonics Archives

02 October 2023 - 04 October 2023

9:30 am - 4:30 pm

EFFECT Photonics #547

Discover Where Light Meets Digital at ECOC2023

Join us from October 2nd-4th, 2023 at ECOC Exhibition in Sec, Glasgow, Scotland, the largest optical communications exhibition in Europe at stand #547.

In the News

June 9, 2023

CEO Marcoccia: EFFECT Photonics combineert het beste van twee werelden Micro-elektronica uit de VS, fotonica uit Nederland

– Link Magazine

Insights

May 31, 2023

Building a Sustainable Future with Fully Integrated PICs

Article first published 27 September 2021, updated 31st May 2023. The demand for data and…

Article first published 27 September 2021, updated 31st May 2023.

The demand for data and other digital services is rising exponentially. From 2010 to 2020, the number of Internet users worldwide doubled, and global internet traffic increased 12-fold. By 2022, internet traffic had doubled yet again. While 5G standards are more energy-efficient per bit than 4G, the total power consumption will be much higher than 4G. Huawei expects that the maximum power consumption of one of their 5G base stations will be 68% higher than their 4G stations. These issues do not just affect the environment but also the bottom lines of communications companies.

Keeping up with the increasing data demand of future networks sustainably will require operators to deploy more optical technologies, such as photonic integrated circuits (PICs), in their access and fronthaul networks.

Integration Impacts Energy Efficiency and Optical Losses

Lately, we have seen many efforts to increase further the integration on a component level across the electronics industry. For example, moving towards greater integration of components in a single chip has yielded significant efficiency benefits in electronics processors. Apple’s recent M1 and M2 processors integrate all electronic functions in a single system-on-chip (SoC) and consume significantly less power than the processors with discrete components used in their previous generations of computers.

Mac Mini Model	Power Consumption (Watts)
Mac Mini Model	Idle	Max
2023,M2	7	5
2020, M1	7	39
2018, Core i7	20	122
2014, Core i5	6	85
2010, Core 2 Duo	10	85
2006, Core Solo or Duo	23	110
2005, PowerPC G4	32	85

Table 1: Comparing the power consumption of a Mac Mini with an M1 SoC chip to previous generations of Mac Minis. [Source: Apple’s website]

Photonics is also achieving greater efficiency gains by following a similar approach to integration. The more active and passive optical components (lasers, modulators, detectors, etc.) manufacturers can integrate on a single chip, the more energy they can save since they avoid coupling losses between discrete components and allow for interactive optimization.

Let’s start by discussing three different levels of device integration for an optical device like a transceiver:

Discrete build – The transceiver components are manufactured through separate processes. The components are then assembled into a single package using different types of interconnections.
Partial integration – Some components are manufactured and integrated on the same chip, but others are manufactured or sourced separately. For example, the transceiver laser can be manufactured separately on a different material and then interconnected to a chip with the other transceiver components.
Full integration – All the components are manufactured on a single chip from a single material simultaneously.

While discrete builds and partial integration have advantages in managing the production yield of the individual components, full integration leads to fewer optical losses and more efficient packaging and testing processes, making them a much better fit in terms of sustainability.

The interconnects required to couple discrete components result in electrical and optical losses that must be compensated with higher transmitter power and more energy consumption. The more interconnects between different components, the higher the losses become. Discrete builds will have the most interconnect points and highest losses. Partial integration reduces the number of interconnect points and losses compared to discrete builds. If these components are made from different optical materials, the interconnections will suffer additional losses.

On the other hand, full integration uses a single chip of the same base material. It does not require lossy interconnections between chips, minimizing optical losses and significantly reducing the energy consumption and footprint of the transceiver device.

Figure 1: Example of integrating a laser to other photonic components through different integration approaches.

More Integration Saves Scarce Resources

When it comes to energy consumption and sustainability, we shouldn’t just think about the energy the PIC consumes but also the energy and carbon footprint of fabricating the chip and assembling the transceiver. To give an example from the electronics sector, a Harvard and Facebook study estimated that for Apple, manufacturing accounts for 74% of their carbon emissions, with integrated circuit manufacturing comprising roughly 33% of Apple’s carbon output. That’s higher than the emissions from product use.

Figure 2: Apple’s carbon-emission breakdown. Manufacturing accounts for 74% of total emissions, and hardware use accounts for 19%. Carbon output from manufacturing integrated circuits (i.e., SoCs, DRAM, and NAND flash memory) is higher than that of hardware use. [Source: ]

Early Testing Avoids Wastage

Testing is another aspect of the manufacturing process that impacts sustainability. The earlier faults can be found in the testing process, the greater the impact on the use of materials and the energy used to process defective chips. Ideally, testing should happen not only on the final, packaged transceiver but in the earlier stages of PIC fabrication, such as measuring after wafer processing or cutting the wafer into smaller dies.

Figure 3: Package level (top row) vs. die level (bottom row) testing. Manufacturers can find faults earlier by testing at the die level, which avoids wasting packaging materials.

Discrete and partial integration approaches do more of their optical testing on the finalized package, after connecting all the different components together. Should just one of the components not pass the testing process, the complete packaged transceiver would need to be discarded, potentially leading to a massive waste of materials as nothing can be ”fixed” or reused at this stage of the manufacturing process.

Full integration enables earlier optical testing on the semiconductor wafer and dies. By testing the dies and wafers directly before packaging, manufacturers need only discard the bad dies rather than the whole package, which saves valuable energy and materials.

Full Integration Drives Sustainability

While communication networks have become more energy-efficient, further technological improvements must continue decreasing the cost of energy per bit and keeping up with the exponential increase in Internet traffic. At the same time, a greater focus is being placed on the importance of sustainability and responsible manufacturing. All the photonic integration approaches we have touched on will play a role in reducing the energy consumption of future networks. However, out of all of them, only full integration is in a position to make a significant contribution to the goals of sustainability and environmentally friendly manufacturing. A fully integrated system-on-chip minimizes optical losses, transceiver energy consumption, power usage, and materials wastage while at the same time ensuring increased energy efficiency of the manufacturing, packaging, and testing process.

Download Article – PDF

Tags: ChipIntegration, Data demand, DataDemand, EFFECT Photonics, Energy consumption reduction, energy efficiency, EnergySavings, Environmental impact, Fully Integrated PICs, Green Future, GreenFuture, Integrated Photonics, Integration benefits, Manufacturing sustainability, Optical technologies, OpticalComponents, photonic integration, PIC, PICs, ResponsibleManufacturing, sustainability telecommunication, Sustainable, Sustainable future, SustainableNetworks, Transceiver optimization

The Fabrication Process Inside a Photonic Foundry

Insights

May 24, 2023

The Fabrication Process Inside a Photonic Foundry

Photonics is one of the enabling technologies of the future. Light is the fastest information…

Photonics is one of the enabling technologies of the future. Light is the fastest information carrier in the universe and can transmit this information while dissipating less heat and energy than electrical signals. Thus, photonics can dramatically increase the speed, reach, and flexibility of communication networks and cope with the ever-growing demand for more data. And it will do so at a lower energy cost, decreasing the Internet’s carbon footprint. Meanwhile, fast and efficient photonic signals have massive potential for sensing and imaging applications in medical devices, automotive LIDAR, agricultural and food diagnostics, and more.

Given its importance, we should discuss the fabrication processes inside photonic semiconductor foundries.

Manufacturing semiconductor chips for photonics and electronics is one of the most complex procedures in the world. For example, back in his university days, EFFECT Photonics co-founder Boudewijn Docter described a fabrication process with 243 steps!

Yuqing Jiao, Associate Professor at the Eindhoven University of Technology (TU/e), explains the fabrication process in a few basic, simplified steps:

Grow or deposit your chip material
Print a pattern on the material
Etch the printed pattern into your material
Do some cleaning and extra surface preparation
Go back to step 1 and repeat as needed

Real life is, of course, a lot more complicated and will require cycling through these steps tens of times, leading to processes with more than 200 total steps. Let’s go through these basic steps in a bit more detail.

Figure 1: Basic steps of a semiconductor fabrication process that are repeated in a single fabrication cycle. An entire wafer manufacturing process requires tens of these cycles.

1. Layer Epitaxy and Deposition: Different chip elements require different semiconductor material layers. These layers can be grown on the semiconductor wafer via a process called epitaxy or deposited via other methods, such as physical or chemical vapor deposition.

Figure 2: Simplified example of PIC elements and their required material layers. Source: Smit et al. (2014)

2. Lithography (i.e., printing): There are a few lithography methods, but the one used for high-volume chip fabrication is projection optical lithography. The semiconductor wafer is coated with aphotosensitive polymer film called a photoresist. Meanwhile, the design layout pattern is transferred to an opaque material called a mask. The optical lithography system projects the mask pattern onto the photoresist. The exposed photoresist is then developed (like photographic film) to complete the pattern printing.

Figure 3: Comparison of different optical lithography approaches. Contact and proximity printing keeps the mask in contact with or close to the sample. Projection printing keeps the mask further away and is initially more expensive, but it is the technology of choice for high-volume manufacturing. Source: J. Shen, University of Waterloo Ph.D. Thesis (2018)

3. Etching: Having “printed” the pattern on the photoresist, it is time to remove (or etch) parts of the semiconductor material to transfer the pattern from the resist into the wafer. Etching techniques can be broadly classified into two categories.

Dry Etching: These processes remove material by bombarding it with ions. Typically, these ions come from a plasma of reactive gases like oxygen, boron, chlorine, etc. This approach is often used to etch a material anisotropically (i.e., in a specific direction).
Wet Etching: These processes involve the removal of material using a liquid reactant. The material to be etched is immersed in the solution, which will dissolve the targeted material layers. This solution usually consists of an acid, such as hydrofluoric acid (HFl), to etch silicon. Wet etching is typically used for etching a material isotropically (i.e., in all directions).

Figure 4: Example of what a semiconductor wafer with resist (red color) on top of it looks like before and after an etching step.

4. Cleaning and Surface Preparation: After etching, a series of steps will clean and prepare the surface before the next cycle.

Passivation: Adding layers of dielectric material (such as silica) to “passivate” the chip and make it more tolerant to environmental effects.
Planarization: Making the surface flat in preparation for future lithography and etching steps.
Metallization: Depositing metal components and films on the wafer. This might be done for future lithography and etching steps or, in the end, to add electrical contacts to the chip.

Figure 5 summarizes how an InP photonic device looks after the steps of layer epitaxy, etching, dielectric deposition and planarization, and metallization.

Figure 6 Cross-section of a semiconductor wafer structure — Figure 5: Cross-section of a semiconductor wafer structure after (a) epitaxial growth, (b) etching, (c) passivation and planarization, (d) metallization.

After this fabrication process ends, the processed wafers are shipped worldwide to be tested and packaged into photonic devices. This is an expensive process we discussed in one of our previous articles.

Takeaways

The process of making photonic integrated circuits is incredibly long and complex, and the steps we described in this article are a mere simplification of the entire process. It requires tremendous knowledge in chip design, fabrication, and testing from experts in different fields worldwide. EFFECT Photonics was founded by people who fabricated these chips themselves, understood the process intimately and developed the connections and network to develop cutting-edge PICs at scale.

Tags: Agricultural, Carbon Footprint, Chip Material, Cleaning, Communication Networks, Deposition, Energy Cost, Epitaxy, Etching, Fabrication Process, Food Diagnostics, Integrated Photonics, LIDAR, Lithography, Manufacturing, Medical Devices, Metallization, Photonic Foundry, Photonics, Semiconductor, Sensing and Imaging, Surface Preparation

Insights

May 3, 2023

The Promise of Integrated Quantum Photonics

Today’s digital society depends heavily on securely transmitting and storing data. One of the oldest…

Today’s digital society depends heavily on securely transmitting and storing data. One of the oldest and most widely used methods to encrypt data is called RSA (Rivest-Shamir-Adleman – the surnames of the algorithm’s designers). However, in 1994 mathematician Peter Shor proved that an ideal quantum computer could find the prime factors of large numbers exponentially more quickly than a conventional computer and thus break RSA encryption within hours or days.

While practical quantum computers are likely decades away from implementing Shor’s algorithm with enough performance and scale to break RSA or similar encryption methods, the potential implications are terrifying for our digital society and our data safety.

Given these risks, arguably the most secure way to protect data and communications is by fighting quantum with quantum: protect your data from quantum computer hacking by using security protocols that harness the power of quantum physics laws. That’s what quantum key distribution (QKD) does.

*Figure 1: Example of a communications link encrypted via QKD* *[Source:* *TU Eindhoven*]

The quantum bits (qubits) used by QKD systems can be photons, electrons, atoms, or any other system that can exist in a quantum state. However, using photons as qubits will likely dominate the quantum communications and QKD application space. We have decades of experience manipulating the properties of photons, such as polarization and phase, to encode qubits. Thanks to optical fiber, we also know how to send photons over long distances with relatively little loss. Besides, optical fiber is already a fundamental component of modern telecommunication networks, so future quantum networks can run on that existing fiber infrastructure. All these signs point towards a new era of quantum photonics.

Photonic QKD devices have been, in some shape or form, commercially available for over 15 years. Still, factors such as the high cost, large size, and the inability to operate over longer distances have slowed their widespread adoption. Many R&D efforts regarding quantum photonics aim to address the size, weight, and power (SWaP) limitations. One way to overcome these limitations and reduce the cost per device would be to integrate every QKD function—generating, manipulating, and detecting photonic qubits—into a single chip.

Integration is Key to Bring Lab Technology into the Market

Bringing quantum products from lab prototypes to fully realized products that can be sold on the market is a complex process that involves several key steps.

One of the biggest challenges in bringing quantum products to market is scaling up the technology from lab prototypes to large-scale production. This requires the development of reliable manufacturing processes and supply chains that can produce high-quality quantum products at scale. Quantum products must be highly performant and reliable to meet the demands of commercial applications. This requires extensive testing and optimization to ensure that the product meets or exceeds the desired specifications.

In addition, quantum products must comply with relevant industry standards and regulations to ensure safety, interoperability, and compatibility with existing infrastructure. This requires close collaboration with regulatory bodies and industry organizations to develop appropriate standards and guidelines.

Photonic integration is a process that makes these goals more attainable for quantum technologies. By taking advantage of existing semiconductor manufacturing systems, quantum technologies can more scale up their production volumes more easily.

Smaller Footprints and Higher Efficiency

One of the most significant advantages of integrated photonics is its ability to miniaturize optical components and systems, making them much smaller, lighter, and more portable than traditional optical devices. This is achieved by leveraging micro- and nano-scale fabrication techniques to create optical components on a chip, which can then be integrated with other electronic and optical components to create a fully functional device.

The miniaturization of optical components and systems is essential for the development of practical quantum technologies, which require compact and portable devices that can be easily integrated into existing systems. For example, compact and portable quantum sensors can be used for medical imaging, geological exploration, and industrial process monitoring. Miniaturized quantum communication devices can be used to secure communication networks and enable secure communication between devices.

Integrated photonics also allows for the creation of complex optical circuits that can be easily integrated with other electronic components, to create fully integrated opto-electronic quantum systems. This is essential for the development of practical quantum computers, which require the integration of a large number of qubits (quantum bits) with control and readout electronics.

Economics of Scale

Wafer scale photonics manufacturing demands a higher upfront investment, but the resulting high-volume production line drives down the cost per device. This economy-of-scale principle is the same one behind electronics manufacturing, and the same must be applied to photonics. The more optical components we can integrate into a single chip, the more can the price of each component decrease. The more optical System-on-Chip (SoC) devices can go into a single wafer, the more can the price of each SoC decrease.

Researchers at the Technical University of Eindhoven and the JePPIX consortium have done some modelling to show how this economy of scale principle would apply to photonics. If production volumes can increase from a few thousands of chips per year to a few millions, the price per optical chip can decrease from thousands of Euros to mere tens of Euros. This must be the goal for the quantum photonics industry.

Figure 2: Modelling of photonic integrated chip (PIC) cost as a function of aggregate number of PICs produced per year. Exponential increases in production lead to an exponential decrease in cost. Source: Model and graph provided by Prof. Meint Smit, TU Eindhoven.

By integrating all optical components on a single chip, we also shift the complexity from the assembly process to the much more efficient and scalable semiconductor wafer process. Assembling and packaging a device by interconnecting multiple photonic chips increases assembly complexity and costs. On the other hand, combining and aligning optical components on a wafer at a high volume is much easier, which drives down the device’s cost.

Takeaways

Overall, bringing quantum products to market requires a multi-disciplinary approach that involves collaboration between scientists, engineers, designers, business professionals, and regulatory bodies to develop and commercialize a high-quality product that meets the needs of its target audience. Integrated photonics offers significant advantages in miniaturization and scale-up potential, which are essential in taking quantum technologies from the lab to the market.

Tags: Economy-of-scale, EFFECT Photonics, Integrated Photonics, miniaturization, Photonics, Photons, Quantum, Quantum products, Qubits, RSA encryption, Wafer Scale Photonics

In the News

April 21, 2023

King Willem Alexander gets a taste of the future in Eindhoven via a deep dive into the world of integrated photonics

– InnovationOrigins

Press Releases

April 20, 2023

Emerging Photonics Ecosystem at the Heart of King’s Visit to Holst Centre and PhotonDelta

Eindhoven, The Netherlands During King Willem-Alexander’s visit to the High Tech Campus in Eindhoven on…

Eindhoven, The Netherlands

During King Willem-Alexander’s visit to the High Tech Campus in Eindhoven on April 20, he gained insight into the value chain of integrated photonics in the Netherlands and Europe from various perspectives. This emerging chip technology is accelerating thanks to a €1.1 billion program led by PhotonDelta. With demonstrations at Holst Centre and roundtable discussions at PhotonDelta, the King learned about the essence of the technology, its applications, and its importance for the future of the Netherlands and Europe.

Ewit Roos, CEO of PhotonDelta, is very pleased with the day’s outcome.

The King’s visit is a tremendous honor for the ecosystem. It underlines once again the importance of integrated photonics for our country. We told him about the applications of integrated photonics for innovations in medical diagnostics, autonomous driving, the agricultural sector, and data communications. PhotonDelta and Holst Centre are central to the development of this new value chain. For the King, this was certainly a wonderful opportunity to get the most complete picture possible of the quality of the unique position of the ecosystem and all the opportunities that still lie ahead.

Ewit Roos, CEO at PhotonDelta

Photonics is all about the interaction between light (photons) and matter. Through photonics, data can be transmitted at the speed of light, reducing energy consumption and increasing efficiency. Integrated photonic chips, considered a key technology worldwide, enable the development of smaller, faster, and energy-efficient devices. This will lead to innovations that will help solve the major challenges of our time and contribute to a healthy and sustainable future.

National Growth Fund

The Netherlands has recognized the opportunities of integrated photonics through the National Growth Fund. PhotonDelta, the ecosystem of organizations in photonic chip technology, has mobilized public and private investment totaling 1.1 billion euros through this fund to transform the Netherlands into a leader in the next generation of semiconductors.

The investment consists of 470 million euros through the growth fund, with the rest coming from other partners and stakeholders. It is all part of the Dutch government’s plan to strengthen the country’s position as a world leader in integrated photonics.

Demonstrations and Roundtable Discussion

The King first visited Holst Centre, a collaboration between the research centers imec and TNO. Researchers from different disciplines develop new technology for photonic chips and prototypes that companies can use for their production process and new products.

The King was given a tour of Holst Centre’s laboratory and attended demonstrations of the application of photonics in various sectors. Representatives from Signify, EFFECT Photonics, Delta Diagnostics, Quix Quantum, and Lionix explained the different stages in the value chain. During this tour, the main focus was on the applications that help solve society’s critical challenges.

Integrated photonics is one of the pillars of Holst Centre’s strategy. By combining the expertise of imec and TNO, many aspects needed in the development and production process can be offered, such as design, prototyping, testing, and manufacturing. We combine the photonic microchip technology of imec in Belgium, the complementary photonic platforms in the Netherlands, the design expertise of imec in the Netherlands, and the optics and systems integration knowledge of TNO to help develop new sustainable solutions in different industries.
Kathleen Philips, director of imec at Holst Centre

The subsequent visit to PhotonDelta, also at the High Tech Campus, began with a presentation on the ecosystem. In recent years, PhotonDelta has grown this community from 12 to 60 stakeholders who together form a value chain that conceives, develops, and makes photonic chips and solutions based on them. The roundtable discussion covered topics such as industrialization, application technology, and European cooperation. Phix Photonics Assembly, Smart Photonics, and Trumpf Photonics Components addressed the challenges and possible solutions in scaling up the most crucial industrialization processes. Following this talk, Synopsys NL and NXP discussed the challenges around application strategies: creating a library of easy-to-use building blocks for new applications. Finally, the European playing field came into focus through PhotonDelta itself and the Ministry of Economic Affairs. This covered Europe’s ambitions around strategic autonomy and the impact of the European Chips Act. Photonic chips have been designated as a key technology by the European Commission. Security of supply for digital technology is the guiding principle in the Chips Act.

Strategic autonomy does not mean developing a copy of the global semiconductor value chain in Europe, but taking unique European positions in these chains where we can be ‘world-class’. This implies interdependence through quality and capacity rather than taking over one-to-one what is already happening elsewhere. Integrated photonics is one such position where Europe can excel.
Ton van Mol, Director TNO at Holst Centre

About PhotonDelta

PhotonDelta is an ecosystem of organizations that conceive, develop and make solutions based on photonic chips. PhotonDelta supports the system by stimulating collaboration between stakeholders, providing funding, and connecting them to the market.

About Holst Centre

Holst Centre, a collaboration of imec and TNO, brings together expertise in wireless sensor technologies and flexible electronics under one roof. The sharing of specific knowledge in an open structure enables the alignment of research and innovation with societal issues in health and vitality, energy and climate, and mobility and industry 5.0.

# # #

More information:

PhotonDelta
Jorn Smeets, Chief Marketing Officer
M: 06 – 1147 8812
E: jorn@photondelta.com
W: www.photondelta.com

Imec at Holst Centre
Carolien van der Leegte, Communicatiemanager imec NL
M: 06 – 1760 4841
E: carolien.vanderleegte@imec.nl
W: www.holstcentre.com
W: www.imec-int.com

TNO at Holst Centre
Sara Joosten, Project Manager Marketing & Communications
M: 06 – 2915 6716
E: sara.joosten@tno.nl
W: www.holstcentre.com
W: www.tno.nl

Tags: €1.1 billion program, autonomous driving, chip technology, data communications, Delta Diagnostics, EFFECT Photonics, Europe, Holst Centre, Integrated Photonics, King Willem-Alexander, Lionix, National Growth Fund, Netherlands, PhotonDelta, Quix Quantum, Semiconductors, Signify

Insights

April 12, 2023

When will the Network Edge go Coherent?

Article first published 27 July 2022, updated 12 April 2023. Network carriers want to provide…

Article first published 27 July 2022, updated 12 April 2023.

Network carriers want to provide communications solutions in all areas: mobile access, cable networks, and fixed access to business customers. They want to provide this extra capacity and innovative and personalized connectivity and entertainment services to their customers.

Deploying only legacy direct detect technologies will not be enough to cover these growing bandwidth and service demands of mobile, cable, and business access networks with the required reach. In several cases, networks must deploy more 100G coherent dense wavelength division multiplexing (DWDM) technology to transmit more information over long distances. Several applications in the optical network edge could benefit from upgrading from 10G DWDM or 100G grey aggregation uplinks to 100G DWDM optics:

Mobile Mid-haul benefits from seamlessly upgrading existing uplinks from 10G to 100G DWDM.
Mobile Backhaul benefits from upgrading their links to 100G IPoDWDM.
Cable Access links could upgrade the uplinks of existing termination devices such as optical line terminals (OLTs) and Converged Cable Access Platforms (CCAPs) from 10G to 100G DWDM.
Business Services could scale enterprise bandwidth beyond single-channel 100G grey links.

However, network providers have often stuck to their 10G DWDM or 100G grey links because the existing 100G DWDM solutions could not check all the required boxes. “Scaled-down” coherent 400ZR solutions had the required reach and tunability but were too expensive and power-hungry for many access network applications. Besides, ports in small to medium IP routers used in most edge deployments often do not support the QSFP-DD form factor commonly used in 400ZR modules but the QSFP28 form factor.

Fortunately, the rise of 100ZR solutions in the QSFP28 form factor is changing the landscape for access networks. “The access market needs a simple, pluggable, low-cost upgrade to the 10G DWDM optics that it has been using for years. 100ZR is that upgrade,” said Scott Wilkinson, Lead Analyst for Optical Components at market research firm Cignal AI. “As access networks migrate from 1G solutions to 10G solutions, 100ZR will be a critical enabling technology.”

In this article, we will discuss how the recent advances in 100ZR solutions will enable the evolution of different segments of the network edge: mobile midhaul and backhaul, business services, and cable.

How Coherent 100G Can Move into Mobile X-haul

The upgrade from 4G to 5G has shifted the radio access network (RAN) from a two-level structure with backhaul and fronthaul in 4G to a three-level structure with back-, mid-, and fronthaul:

Fronthaul is the segment between the active antenna unit (AAU) and the distributed unit (DU)
Midhaul is the segment from DU to the centralized unit (CU)
Backhaul is the segment from CU to the core network.

Figure 1: Simplified diagram that shows and compares the building blocks of 4G (left) and 5G (right) access networks and the links between these blocks.

The initial rollout of 5G has already happened in most developed countries, with many operators upgrading their 1G SFPs transceiver to 10G SFP+ devices. Some of these 10G solutions had DWDM technology; many were single-channel grey transceivers. However, mobile networks must move to the next phase of 5G deployments, which requires installing and aggregating more and smaller base stations to exponentially increase the number of devices connected to the network.

These mature phases of 5G deployment will require operators to continue scaling fiber capacity cost-effectively with more widespread 10G DWDM SFP+ solutions and 25G SFP28 transceivers. These upgrades will put greater pressure on the aggregation segments of mobile backhaul and midhaul. These network segments commonly used link aggregation of multiple 10G DWDM links into a higher bandwidth group (such as 4x10G). However, this link aggregation requires splitting up larger traffic streams and can be complex to integrate across an access ring. A single 100G uplink would reduce the need for such link aggregation and simplify the network setup and operations. If you want to know more about the potential market and reach of this link aggregation upgrade, we recommend reading the recent Cignal AI report on 100ZR technologies.

Cable Migration to 10G PON Will Drive the Use of Coherent 100G Uplinks

According to Cignal AI’s 100ZR report, the biggest driver of 100ZR use will come from multiplexing fixed access network links upgrading from 1G to 10G. This trend will be reflected in cable networks’ long-awaited migration from Gigabit Passive Optical Networks (GPON) to 10G PON. This evolution is primarily guided by the new DOCSIS 4.0 standard, which promises 10Gbps download speeds for customers and will require several hardware upgrades in cable networks.

To multiplex these new larger 10Gbps customer links, cable providers and network operators need to upgrade their optical line terminals (OLTs) and Converged Cable Access Platforms (CCAPs) from 10G to 100G DWDM uplinks. Many of these new optical hubs will support up to 40 or 80 optical distribution networks (ODNs), too, so the previous approach of aggregating multiple 10G DWDM uplinks will not be enough to handle this increased capacity and higher number of channels.

Anticipating such needs, the non-profit R&D organization CableLabs has recently pushed to develop a 100G Coherent PON (C-PON) standard. Their proposal offers 100 Gbps per wavelength at a maximum reach of 80 km and up to a 1:512 split ratio. CableLabs anticipates C-PON and its 100G capabilities will play a significant role not just in cable optical network aggregation but in other use cases such as mobile x-haul, fiber-to-the-building (FTTB), long-reach rural scenarios, and distributed access networks.

Towards 100G Coherent and QSFP28 in Business Services

Almost every organization uses the cloud in some capacity, whether for development and test resources or software-as-a-service applications. While the cost and flexibility of the cloud are compelling, its use requires fast, high-bandwidth wide-area connectivity to make cloud-based applications work as they should.

Similarly to cable networks, these needs will require enterprises to upgrade their existing 1G Ethernet private lines to 10G Ethernet, which will also drive a greater need for 100G coherent uplinks. Cable providers and operators will also want to take advantage of their upgraded 10G PON networks and expand the reach and capacity of their business services.

The business and enterprise services sector was the earliest adopter of 100G coherent uplinks, deploying “scaled-down” 400ZR transceivers in the QSFP-DD form factor since they were the solution available at the time. However, these QSFP-DD slots also support QSFP28 form factors, so the rise of QSFP 100ZR solutions will provide these enterprise applications with a more attractive upgrade with lower cost and power consumption. These QSFP28 solutions had struggled to become more widespread before because they required the development of new, low-power digital signal processors (DSPs), but DSP developers and vendors are keenly jumping on board the 100ZR train and have announced their development projects: Acacia, Coherent/ADVA, Marvell/InnoLight, and Marvell/OE Solutions. This is also why EFFECT Photonics has announced its plans to co-develop a 100G DSP with Credo Semiconductor that best fits 100ZR solutions in the QSFP28 form factor.

Figure : Comparison between QSFP-DD and QSFP-28 form factors for 100G applications. — Figure 2 : Comparison between QSFP-DD and QSFP-28 form factors for 100G applications.

Takeaways

In the coming years, 100G coherent uplinks will become increasingly widespread in deployments and applications throughout the network edge. Some mobile access networks use cases must upgrade their existing 10G DWDM link aggregation into a single coherent 100G DWDM uplink. Meanwhile, cable networks and business services are upgrading their customer links from 1Gbps to 10Gbps, and this migration will be the major factor that will increase the demand for coherent 100G uplinks. For carriers who provide converged cable/mobile access, these upgrades to 100G uplinks will enable opportunities to overlay more business services and mobile traffic into their existing cable networks.

As the QSFP28 100ZR ecosystem expands, production will scale up, and these solutions will become more widespread and affordable, opening up even more use cases in access networks.

Tags: 5G, access, aggregation, backhaul, capacity, DWDM, fronthaul, Integrated Photonics, LightCounting, metro, midhaul, mobile, mobile access, network, optical networking, optical technology, photonic integrated chip, photonic integration, Photonics, PIC, PON, programmable photonic system-on-chip, solutions, technology

In the News

April 7, 2023

Delta Dialogues – April 2023 – Looking back at OFC San Diego ’23

– PhotonDelta

In the News

March 23, 2023

Roberto Marcoccia – Interview at OFC 2023

– LightwaveOnline

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Integrated Photonics

Explore Our ECOC2023 Demos:

Integration Impacts Energy Efficiency and Optical Losses

More Integration Saves Scarce Resources

Early Testing Avoids Wastage

Full Integration Drives Sustainability

Takeaways

Integration is Key to Bring Lab Technology into the Market

Smaller Footprints and Higher Efficiency

Economics of Scale

Takeaways

Eindhoven, The Netherlands

National Growth Fund

Demonstrations and Roundtable Discussion

About PhotonDelta

About Holst Centre

How Coherent 100G Can Move into Mobile X-haul

Cable Migration to 10G PON Will Drive the Use of Coherent 100G Uplinks

Towards 100G Coherent and QSFP28 in Business Services

Takeaways

Telecom/Datacom

Emerging Industries

DSP & FEC

Ultra Pure Light Sources

Ecosystems

Pluggable Modules – Direct Detect

Pluggable Modules – Coherent

Sub-Assemblies

ASICs

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Insights

Press Releases

In the News

Events

Careers

Knowledge Center

Company Info

Contact Us