IBM Takes A Further Step Towards Integrated Photonics

IBM engineers in New York and Zurich, Switzerland and IBM Systems Unit have designed and tested a fully integrated wavelength multiplexed silicon photonics chip, which the company says will soon enable manufacturing of 100Gbps optical transceivers.

The chip, the product of 15 years of silicon photonics research, demonstrates transmission and reception of high-speed data using four laser channels each operating as an independent 25Gbps optical channel. The reference design targets datacentre interconnects with a range up to 2km.

"The lasers are brought in from off-chip in order to be modulated, but eventually we hope to incorporate III-V lasers right on the chip," Will Green, manager of the silicon photonics group at IBM Research told the electronics paper EE Times.

Most of the optical interconnect solutions employed within datacentres as of today are based upon VCSEL technology, where the optical signals are transported via multimode optical fibre.

Demands for increased distance and data rate between ports, due to cloud services for example, are driving the development of cost-effective single-mode optical interconnect technologies, which can overcome the bandwidth-distance limitations inherent to multimode VCSEL links.

IBM say its CMOS Integrated Nano-Photonics Technology provides an economical solution to extend the reach and data rates of optical links. The essential parts of an optical transceiver, both electrical and optical, can be combined monolithically on one silicon chip, and are designed to work with standard silicon chip manufacturing processes.