Optical Networking, Redefined.
March 16, 2023

Key Takeaways From OFC 2023:  Interoperability is Key 

Jennifer Grace, Technical Writer at Precision OT, attended OFC 2023 in San Diego, California. Here are her main takeaways from the highly anticipated event.


In the OFC Plenary session on Tuesday morning, 3 distinguished speakers delivered a message about global digitalization and what it means in terms of people, technology, and our environment.   

Patricia Obo-Nai, CEO of Vodafone Ghana, emphasized the need for digitalization to be accessible to all.  Highlighting some key barriers to digital connectivity in Africa, Patricia pointed to poor network coverage, low device penetration, low digital literacy, and a lack of relevant digital content.   She emphasized that success can only be achieved through partnership.  Urging the OFC community to consider network accessibility for everyone when discussing challenges in optical fiber communications, she said, “No one agency or company can address this problem. We must all work together to ensure that we leave no one behind.”  

Arista CEO Jayshree Ullal spoke of pushing the limits of electrical and soon, optical technology, with artificial intelligence (AI). The petascale era of cloud networking puts increasing demands on the systems and optics required to run new AI/ML-driven network architectures.  Starting with processors having Terabits of GPU,  and very, VERY high end servers that continue to get faster and faster and denser and denser,  AI is already powering nearly everything we do online.  1.6TB and higher networking requires a new class of optical transceivers,  advanced silicon technology, new optical materials and advanced Linear Drive (LD) interfaces. 

Corning CEO Wendell Weeks expressed his faith in OFC’s collaborative capabilities.  “Create an obstacle for THIS crowd, and we will find a way.”  Framed in Mr. Weeks’ office is a purchase order of the first sale of glass for manufacturing light bulbs, signed by Thomas Edison himself. Edison had come to Corning and asked “How do I make [lightbulbs] economical?”Now, as a network of optical fiber has become vital to our daily lives and advancement, Weeks called to mind the multitude of obstacles in the optical fiber communications industry that we’ve already overcome and those we’ll overcome in the future.   We need to use less energy/bit while at the same time increasing capacity and speed.  We have to make the right decisions (environmentally) as we move forward, ideally expending less than a pico joule of energy per bit.  Soon “the obstacles will become THE WAY”,  Weeks said. “We are expanding the bandwidth of human potential.” 

OIF 400ZR Interoperability Demo 

Throughout the conference, interoperability was mentioned as a key for mass adoption of new technology.   Precision OT was excited and proud to participate in the 400ZR Interoperability Demo organized by the Optical Internetworking Forum (OIF). As an OIF standard, 400ZR coherent optics provide 400Gbps of bandwidth over a single optical wavelength using DWDM. This technology enables point to point 400GbE data center interconnect (DCI) for distances up to 80-120km with the use of amplifiers but without the need for specialized optical transport equipment. The 400ZR standard was born out of a hyperscale need for enhanced DCI performance using small form factor pluggable modules like QSFP-DD and OSFP.  OIF celebrated their 25th anniversary with a reception at their very popular booth hosting the 400ZR Interoperability Demo. 

Coherent Optics in the Access Network 

 While 400G ZR was widely discussed and applauded at OFC’23, it’s recognized that not everyone is ready to jump onboard.  What’s preventing some folks from rushing to 400G ZR?  In addition to its high power requirement, it requires the purchase of routers and switches with 400G ports, (ie. new capital expenditures & upgrades).   As a result of their findings in a study of Coherent at the Network EdgeCignal AI’s forecast for 100ZR module shipments was doubled for 2025This is mostly driven by the fact that select transceiver companies have come out with a QSFP28 version of 100G coherent.  The original forecast was based on QSFP-DD which is a relatively high power device so it doesn’t fit a lot of applications the way a coherent QSFP28 would.  Not every location needs 400G coherent and not all hosts will support QSFP-DD 400G pluggable optics. With the QSFP28 ZR, 100G coherent signals are possible utilizing existing equipment/ports and in some cases, avoiding equipment expenditures while conserving power.  400ZR works very well for DCI applications and/or small volume.  But to go out into the Access space where power is critical, having a way to do this in a QSFP28 form factor is a real paradigm shift.   

Passive Optical Network (PON): Coming To a Room Near You! 

PON continues to expand its reach further into the Access space with one of the most recent applications, Fiber to the Room (FTTR).  High data traffic and increasing numbers of smart devices within the home put a strain on traditional Wi-Fi technology.  No longer is it enough to have fiber to the “last mile”.  Many homes now need it to the “last meter”.  A subset of ITU Study Group 15 (SG15), the G.fin project in ITU-T SG15 Q18 specifies FTTR use cases, architecture, PMD and protocols.  As described in an OFC  short course by Dr. Yuanqiu Luo, the path from each G.fin user consists of two parts: home PON and access PON, where the home PON includes Optical Network Units (ONUs) in multiple rooms within the house.  Room ONUs,  also called G.fin end-points, provide the advantages of fiber connectivity to each user.  A G.fin head-end within the home is the gateway to connect room ONUs to the Optical Line Terminal (OLT). 

Photonic Integrated Circuits (PICs) 

PICs were another hot topic at OFC ’23.  Containing 100s of optical components on a single chip, photonic integrated circuits (PICs) offer more functionality, reliability, and scalability than their discrete optical component predecessors.  The most sophisticated PICs to date contain over 1000 optical components on single chipPICs can and have been created by leveraging the same manufacturing processes as the far more mature electrical integrated circuit (EIC) industry.  While Datacom/Telecom applications are the highest volume application for the narrow linewidth silicon substrates used in PICs,  several other high volume applications help drive economy of scale including LIDAR, Optical Gyroscopes, AR/VR, Optical and Quantum Computing and Biosensors. The field itself is growing, with approximately 6000 papers published per year on silicon photonics and registering a CAGR of 28.81% during the forecast period 2022-2027 per a market analysis by Mordor Intelligence.  Some of the research presented at OFC is supported by DARPA’s EPIC program which has had a significant impact on advancing PICs for router technology in particular.   

Final Thoughts

While this summary merely scratches the surface of all the technology discussed and demonstrated at OFC ‘23, rest assured the systems engineering and integration experts at Precision OT are up to speed and ready to answer your optical networking questions.  Contact us!  

About The Author: Jennifer Grace is a Technical Writer at Precision Optical Technologies with more than 20 years’ experience in product development, manufacturing and business strategy. With an extensive background in optical and electrical components and systems, Jennifer is focused on sharing Precision OT’s knowledge of optical fiber communications products and technology.