Novel silicon photonics product for next-generation data centres For use in optical communications, optical systems should be designed to be compact and efficient in terms of power and bandwidth. EU-funded researchers successfully developed novel silicon photonics technology that keeps pace with the requirements driving the datacom industry. Digital Economy © Purestock, Thinkstock Coherent detection with wavelength-division multiplexing is a promising method for achieving high spectral and power efficiency in long-haul communications. The technique involves mixing an input signal with a local oscillator in a non-linear device. The resulting mixing product is detected after filtering out the original signal and the local oscillator frequency. However, the coherent detection scheme requires very good control of the local oscillator optical frequency. Mode-locking techniques that solely involve tuning a pair of pump lasers and on-chip microresonators are a powerful way of controlling light pulses. Within the EU-funded project COWDM (Compact silicon photonics coherent WDM transceiver), researchers developed an optical transceiver-receiver pair utilising optical frequency combs generated in on-chip resonators containing non-linear elements. Optical parametric oscillators – consisting of an optical resonator and an optical non-linear system – hold great promise for compact sources of coherent light. The team successfully designed transmitter and receiver subsystems based on integrated silicon photonics technology. Newly developed ring modulators, hybrid couplers and reconfigurable add-drop multiplexers were all integrated in the silicon photonics transceivers. In addition, the team produced microresonators (microtoroids) and assessed their suitability for different transceiver architectures. Reducing power consumption and space in data centres, the innovative silicon photonics transceiver solution is expected to play a key role in next-generation data centre interconnects. Project results were disseminated in three papers. Keywords Silicon photonics, data centres, oscillator, microresonators, COWDM, transceiver-receiver
