Optimization of Balanced Detector for Coherent Receiver on Generic InP Platform by Particle Swarm Optimization

The balanced photodetector (BPD) is an important component for high-speed coherent receiver. An optimization strategy of waveguide-based multi-quantum well (MQW) BPDs, operating at 1550 nm is demonstrated on a generic InP platform. Design parameters of BPD are optimized towards achieving the highest bandwidth for a responsivity through an algorithm based on Particle Swarm Optimization (PSO). We do so by establishing an equivalent circuit model of BPD and analyzing its opto-electronic transfer function through numerical modelling. We address the major bottlenecks of high-speed BPDs: transit time of generated carriers and RC loading in our model. The algorithm is able to provide multiple combinations of design parameters with the same output characteristics. The design methodology to integrate laser with optimized BPD is presented to successfully implement a coherent receiver.