High receiver responsivity and low dark current of InP-based pin-photodiode array monolithically integrated with 90° hybrid and spot-size converter using selective embedding regrowth

Abstract

The InP-based pin-photodiode array monolithically integrated with a 90° hybrid and spot-size converters was realized using selective embedding regrowth for compact 100 Gb/s coherent receivers. The low dark current of less than 500 pA up to 85 °C was attained by InP passivation effect in four-channel pin-photodiodes. As a receiver using these photodiode arrays, a receiver responsivity including total loss of 6.7 dB in the 90° hybrid and intrinsic loss of 3 dB in the polarization beam splitter was higher than 0.060 A/W between −5 °C and 85 °C through the integration of the spot-size converter. Responsivity imbalance of the In-phase and Quadrature channels was also less than 0.5 dB over the C-band.