  Balanced photodetector (BPD) is an important component for high-speed
coherent receiver. Optimization strategy of waveguide-based multi-quantum well
(MQW) BPDs, operating at 1550 nm is demonstrated on 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. Design
methodology to integrate laser with optimized BPD is presented to successfully
implement coherent receiver.
