How Silicon Photonics Are Helping Data Centers Keep Up with the IoT, Big Data, and Cloud Computing

The use of photonics in networking and electronics has been considered one of many possible solutions for handling the growing demand on data centers, where Moore’s Law is rapidly becoming obsolete. Here's a look at some of the photonics hardware and projects being implemented in the industry.

It is becoming increasingly more expensive to operate data centers and keep up with networking demands. Widespread IoT functionality, machine learning applications, and cloud computing are increasing demands on networks. Because of this, the ability to lower power costs while simultaneously increasing speed is precisely the solution needed for data center capacity and computing capability to continue to increase.
Many top computing companies have been researching possible solutions, with silicon photonics rising to become a major focus.

Rockley Photonics Hybrid Integrated Circuit Solution

Rockley Photonics was recognized recently with the 2017 Frost & Sullivan Global Data Center Networking Infrastructure Technology Innovation Award for the company’s silicon-photonics integrated circuits, which combine photonic packet switching and CMOS technology.
This hybrid packet switching integrated circuit combines the functions of ASIC switches for packet processing/buffering/switching, optical transceivers, digital packet processing chips, and photonic interfacing into one device. The ICs are capable of lane rates of 25 Gbps and Ethernet speeds of 100 Gbps.

Image courtesy of Rockley Photonics

Rockley Photonics anticipates that this one-component solution will lower the cost of data center upgrades to photonic-based interfacing, while simultaneously decreasing the power demands of data centers and improving networking capacity in mega data centers.

IBM’s Approach to Overcoming Challenges

There have been many challenges in the development of viable silicon photonics that have made the technology transition a relatively slow process. One of the solutions IBM is looking toward is taking advantage of already existing micro-electronic manufacturing capacities and developing silicon photonic devices which can be manufactured in these facilities.
There are two main challenges IBM faces in this respect: overcoming mode transformation between photonic waveguides and single-mode optical fibers (similar to the concept of impedance matching), and achieving the precision required for the assembly of silicon photonics which only has a tolerance of 1-2 um for single-mode optics.

Images courtesy of IBM Research

IBM’s solution to both of these problems includes using adiabatic mode evolution by propagating light through a specialized homogenous medium and designing components so that they are self-aligning during the assembly process.

Intel’s Silicon Photonics Solutions

Intel can boast that they announced the first hybrid silicon laser a decade ago. They also currently have two silicon photonic optical transceivers commercially available for data centers which began shipping in August 2016. Microsoft has been utilizing the technology in its Azure data centers since June 2016.
The transceivers are said to be fabricated “just like CMOS chips”, making production relatively low cost.

Intel's 100G CWDM4 QSFP28 and 100G PSM4 QSFP28 silicon photonic optical transceivers. Images courtesy of Intel.

The 16-year effort by Intel to develop silicon photonic devices is outlined in great detail in a report published by 451 Research, an information technology research and advisory group. In the report, the group highlights Intel’s choice in making use of already-existing manufacturing facilities and techniques and adapting them to manufacture optical transceivers.
Check out their projected roadmap of how the technology will be adapted in the future.



Featured image courtesy of Intel.