Hybrid III-V on Si Photonic Integrated Circuits for High-Speed Optical Communications: Roadmap and Perspectives

We review some of our latest contributions for on-chip high-speed optical communications using the hybrid III-V-on-Si platform. Fast tunable lasers for metro-access networks are demonstrated, showing wavelength switching of around ~ 1 ns, a tunable wavelength span of 45 nm and a coupled output power greater than 1 mW. Additionally, fully integrated coherent transceivers for long-haul telecommunications are also discussed, providing the first experimental demonstration of an integrated coherent transceiver that comprises, for the transmitter i) the laser, ii) the high-speed Mach-Zehnder modulator and iii) the semiconductor optical amplifier. For the receiver: i) the coherent 90° hybrid mixer, ii) the local oscillator and iii) an array of photodiodes. A figure of merit of V _π L _π = 2.2 V cm was measured for the Mach-Zehnder modulator, with a 3 dB electro-optical bandwidth of 14 GHz and an open eye diagram (6.7 dB of extinction ratio) at 25 GHz. Regarding the coherent receiver, a maximum photodiode responsivity of 0.9 A/W was retrieved, with an in-quadrature symbol constellation presenting a quality factor of around 11.1 dB at 28 GBd. These results put in perspective the potential of the hybrid III-V on Si platform to implement compact on-chip high-speed communication systems that include the gain-chip components (lasers and SOAs) with unprecedented performance.