Adoption of Silicon Photonics is Reaching an Inflection Point
LightCounting Releases the 6th Edition of Integrated Optical Devices Report
Many in the industry have predicted that silicon photonics (SiP) will enable inexpensive, mass-produced optical connectivity, radically changing the optical components and modules industry. Forecasting the timing of such transitions is most challenging. Just like with many other radical changes, nothing seems to happen for a while until suddenly a change is prominent. We might be reaching such an inflection point in the adoption of SiP and the transformation of our industry.
The figure below shows our latest forecast for optical transceivers, AOCs and EOMs, illustrating the growing share of SiP-based products. It is projected to increase from 14% in 2018-2019 to 45% by 2025, as the market returns to double-digit growth over the next 5 years. The industry seems to be prepared for such a radical transition. Customers want it, and suppliers are ready to deliver.
Figure: Global market for optical transceivers, AOCs and EOMs by technology
Why now? It took almost a decade for the majority of customers to warm up to SiP technology and recognize the limitations of InP and GaAs optics in terms of speed, reliability, and integration with CMOS electronics. Massive adoption of optical engines co-packaged with switching ASICs and FPGAs seems to be just around the corner. Even if it continues to be within reach for the next decade, there are several optical transceivers on the market now, enabled by 2.5D and 3D multi-chip integration. Not all of these co-packaged chips are based on CMOS technology, but the share of CMOS is growing, and it's impacting the optics as well.
Acacia’s latest version of high-speed coherent DWDM transceivers is a great example. It combines a SiP-based photonic integrated circuit (PIC) with a CMOS-based DSP into a single 3D-stacked assembly, which also includes a modulator driver and TIA chips. The chips are interconnected by vertical copper pillars, to reduce power losses on RF connectors and increase speed. It's powered by an external narrow-linewidth tunable laser, which requires temperature stabilization, but the SiP-based PIC works fine in one stack with the hot ASIC.
The first 3D stacked design of an Ethernet transceiver was introduced by Luxtera (now Cisco) a few years ago. 2.5D integration combines multiple chips by placing them on a common substrate rather than stacking them vertically. This approach is more suitable for integrating chips made of different materials while offering similar benefits of higher speed and lower power. However, the better performance and reliability of high-speed SiP-based modulators tilts the scale in favor of this technology for both 2.5D and 3D integration.
The first 400GbE transceivers, sold in 2019-2020, use InP-based devices, but we expect that SiP-based 400GbE products will gain share in 2021-2025. LightCounting’s list of TOP 10 transceiver suppliers included three switch vendors in 2019: Broadcom, Cisco, and Intel. All these companies are committed to CMOS and SiP technologies, and they will be among the leading suppliers of 400GbE transceivers.
Some of the first coherent DWDM 400ZR modules will also use InP modulators, but a majority will be based on SiP, as sales of this product will start in 2020. Apart from Acacia, which is now becoming part of Cisco, Ciena, Huawei, Infinera, Nokia, and ZTE also plan to manufacture 400ZR and ZR+ modules. Most of these companies are likely to use SiP for 400ZR/ZR+ designs.
LightCounting’s Integrated Optical Devices Report provides an in-depth analysis of the impact made by integration on the market for optical transceivers and related components in 2010-2019. It also presents a forecast for shipments and sales of discrete and integrated products based on InP, GaAs, and SiP technologies for 2020–2025. The forecast is segmented by main applications, including Ethernet, WDM, Active Optical Cables (AOCs), Embedded Optical Modules (EOMs), and a few others. Products are sorted by data rate, reach, and form factor into more than 150 categories. The report also discusses the supply chain for SiP products and profiles of many start-up companies developing integrated optical devices. Additionally included is a forecast for the adoption of co-packaged optics in 2023-2028.
More information on the report is available at: https://www.lightcounting.com/products/IOD