Silicon Photonics: Datacom, yes, but not only…

Article By : Yole Développement

Silicon photonics is expected to be a key technology for network switches in the next five years with CPO, and will enable new applications. The number of companies interested in silicon photonics is impressive...

Silicon photonics market shows a sustained growth and keeps attracting new players, especially with co-packaged emerging technologies. Yole Développement (Yole) expects an overall silicon photonics market reaching US$3.9 billion in 2025.

In 2019, shipments of silicon photonic transceivers for datacenters reached almost 3.5 million units, for revenues worth US$364 million. And the success story does not stop there… “Indeed, this is an impressive growth since most products appeared in 2016 and 2017,”reminds Alexis Debray, Technology & Market Analyst at Yole Développement. And he explains: “Silicon photonic transceivers are reported to have better reliability and lower price than transceivers using legacy optics. And we see lot of new companies that are focusing their activities on the development of transceivers to penetrate the silicon photonics world for telecom/datacom applications.” And this growth is expected to continue in coming years, explains Yole in its Silicon photonics report, 2020 edition, Silicon Photonics Market & Technology 2020.

So what does this story make so successful?

The main reason is focused on the global network traffic. Therefore, it doubles every three years thanks to applications in Cloud, video streaming, and IoT. As a result, the silicon photonic transceiver market is directly impacted. Yole’s analysts expect this industry to be worth US$3.6 billion in 2025 with 24 million units shipped.

In parallel, the development of silicon photonic transceivers as an industry with millions of units shipped has resulted in the emergence of an ecosystem with PDKs , design rules, simulation software, testing equipment, and foundries. This ecosystem is enabling new companies to easily access this technology and enter new applications. Genalyte, a Californian company, releases immunoassays using silicon photonics this year. A first announcement has been done last week: read it on i-Micronews. Fiber optic gyroscopes using silicon photonics were announced for this year by KVH. Electronic noses, LiDARs, and OCT , all relying on silicon photonics, are under development and expected in coming years.

Yole and its partner System Plus Consulting, in collaboration with Jean-Louis Malinge, a world-renowned telecommunication & photonics expert, investigate the silicon photonics industry and deliver significant analyses dedicated to the silicon photonics technologies and its industry. System Plus Consulting proposes a special case study focused on Intel’s silicon photonic transceiver to illustrate latest innovations and technical choices made by the leading company: Intel Silicon Photonic 100G CWDM4 QFSP28 Transceiver report.

Silicon photonics is a great technology for optical communications, allowing more reliable and cheaper products, and enabling the high data rate densities that will be needed in five years for switches. It has attracted important players in datacom infrastructure.

Cisco acquired Lightwire in 2012 for US$217 million, and in 2019 it bought both Luxtera for US$660 million and Acacia for US$2.6 billion. Luxtera has 35% of the market share in silicon photonic transceivers for datacom, while Acacia is the main player for silicon photonic transceivers for long haul.

Intel, which is marketing servers, has 60% market share in silicon photonic transceivers for datacom. Intel is one of the leading Silicon photonics companies, without doubts. Indeed, in just a few short years, Intel has already shipped more than 3 million units of its 100G pluggable transceivers.

“With its CWDM4 100G technology, Intel is the first in the world to offer a silicon photonic solution up to 10km for direct detection,” explains Sylvain Hallereau, Senior Technology & Cost Analyst, System Plus Consulting. “The 100G PSM4 and CWDM4 represent the first step, with Intel’s 200G and 400G products expected to enter volume production in the second half of 2020.”
Intel’s transceiver reuses a part of the PSM4 technology, but many other facets represent new approaches from the leading company.

The transceiver comes with two separated lines with several dies. The transmitter silicon photonic die integrates four InP lasers for the four wavelengths, in a different configuration than the PSM4. On the same die, a Mach-Zehnder modulator is added to modulate the signal, but the CWDM MZI is more complex. Light extraction is performed by the edge of the die and not by a mirror. Other components have been added to the system in order to focus or isolate the signal. Data is processed by using a four-channel 25G optical CDR component from MACOM.

The receiver function is performed by four germanium photodiode dies and a TIA circuit. The Ge photodiodes are manufactured on a dedicated SOI substrate, and an optical demultiplexer is assembled between the SiGe photodiodes and the fiber optic.

System Plus Consulting’s analysts describe and analyze Intel’s potential in terms of packaging and photonics. Within a very small form factor, Intel has successfully managed to integrate four lasers, a photonic driver, optical modules, CDR functionality, high-performance photo-diodes, two advanced substrates, and materials for optic. This report clearly points out the impressive technology developed by Intel by showing how the chipset configuration is implemented and describing in detail the transmitter and receiver line.

“This tendency of vertical integration is continuing, and silicon photonics seems to be an opportunity for system companies to enter the transceiver market”,asserts Eric Mounier, PhD. Fellow Analyst at Yole. “This is the case for Juniper Networks, a leader in routers and switches, which acquired Aurrion in 2016 for US$165 million and which is preparing 400ZR silicon photonics transceivers. Fujitsu Optical Networks is proposing 400ZR silicon photonic transceivers. Nokia acquired Elenion in February 2020.”

However, diversity is key for businesses to operate smoothly. Other companies like Inphi and NeoPhotonics are proposing silicon photonic transceivers with strong technologies. HPE is developing a platform for the development of silicon photonics with several partners. China also has strong ambitions for 5G and Cloud datacenters. Several Chinese companies are entering the silicon photonic market, usually with Western companies. Alibaba Cloud is collaborating with Elenion, Hengtong with Rockley Photonics, and Broadex with Sicoya.

Silicon photonics has shipped millions of units of optical transceivers. It is expected to be a key technology for network switches in the next five years with CPO. The number of companies interested in silicon photonics is impressive. Silicon photonics has become an established industry and will enable new applications in coming years.

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