Silicon photonics to feed growing appetite for bandwidth

Belgium-based research institute IMEC has developed a platform that uses silicon photonics in high-speed optical links to support the growing bandwidth needs of cloud datacentres.

According to IMEC, which is holding a technology forum in Singapore in September 2017, the most advanced cloud datacentres are currently using optical links and transceivers with a capacity of 100Gbps. By 2019, this is expected to increase to 400Gbps, followed by 1.6Tbps by 2022.

This increase in demand for bandwidth requires a rethink of optical link technology. Not only do these links need to support a range of at least 500 meters, they also need to be made at a lower cost and in greater quantities.

In recent years, there has been growing interest in the use of silicon photonics to produce optical components for data links.

“The big benefit of this technology is that the optical components can be produced using the same advanced devices with which microchips are also made,” IMEC said.

“This makes silicon photonics components relatively cheap. Better still, they make a high integration density possible, while consuming less energy and guaranteeing a high yield,” it added.

According to 451 Research, the technology will also have a clear impact on large datacentre cost and enable new ‘rack-scale’ system and application architectures.

IMEC are not the only ones exploring the use of silicon photonics in optical data links. Intel, Oracle and IBM are doing so as well. In 2016, Intel unveiled its PSM4 silicon photonics optical transceiver that can deliver 100Gbps over a distance of 2km.

IMEC’s technology, however, is capable of supporting a bandwidth of 896Gbps, by integrating photodetectors and modulators on a single transceiver chip, and using space division multiplexing.

The modulators have a bandwidth of 56Gbps per wavelength in the NRZ-OOK format and capability for 100Gbps per wavelength in the PAM-4 format.

Besides data links, IMEC said silicon photonics also has strong potential for a variety of sensing applications, including Lidar sensors used by autonomous vehicles and chemical (spectroscopic) sensing.

In Singapore, a research team from the Institute of Microelectronics under the Agency for Science, Technology and Research clinched a President’s Technology Award in 2010 for their progress in developing silicon photonic devices with applications in high-speed optical interconnects and light-emitters.