Silicon photonic switch-based optical equalization for mitigating pulsewidth distortion

Optical transmitters typically require electrical pre-amplification using driver amplifiers to optimize the optical modulation depth. To enhance the detection sensitivity and optimize the overall link budget, equalization is required to compensate for undesired signal distortion induced by the transmitter. In this paper, we propose and demonstrate a novel optical equalization scheme using a silicon photonic micro-ring resonator (MRR)-based switching circuit for mitigating driver-amplifier-induced pulsewidth distortion. The switching circuit simultaneously functions as a spatial optical switch as well as a two-stage optical bandpass filter for optical equalization. The experimental results indicate a 4.5-dB detection sensitivity enhancement at a data rate of 12.5 Gbits/s. The proposed approach is robust to different levels of pulsewidth distortion without additional signal processing, and has possibilities to support higher data rates by adjusting the MRR parameters.