Silicon Photonics for 100Gbaud

We reviewed recent breakthroughs on silicon photonic for 100Gbaud operation. Recent progress on high-speed Ge photodetector and carrier depletion modulator promises 100Gbaud optical transceivers with all-silicon material platform for commercial applications. We achieved high performance high-speed all-silicon photonics carrier-depletion Mach–Zehnder modulation by co-optimization of doping and device design assisted with an accurate electro-optical (EO) model. We reported all-silicon Mach–Zehnder modulator with a measured 6 dB EO bandwidth of >60 GHz by using a medium doping and 2 mm long phase shifter. We experimentally demonstrated 120Gbaud QPSK and 100Gbaud 32QAM operations using a high performance all-silicon in-phase/quadrature (IQ) modulator with extinction ratio of >25 dB, moderate
${{\boldsymbol{V}}_{\boldsymbol{\pi }}}$
of 6.3 V, and 6 dB electro-optic bandwidth of 50 GHz employing practical Nyquist filter and linear compensation in commercial arbitrary wave generator (AWG) and optical modulation analyzer (OMA). We studied both performance optimization and limitation. Our results show that BER performance can be optimized by pre-equalization (Pre-EQ) method for bandwidth-limited silicon photonic modulators. However, the performance on BER and modulation loss is strongly affected by the equalization bandwidth due to peak-to-average-power-ratio (PAPR). The frequency at fast roll-off of transmitter response is more critical than 3 dB electro-optic bandwidth when Pre-EQ is used for bandwidth compensation.