Monolithic integration of InP-based waveguide photodiodes with MIM capacitors for compact coherent receiver

We have demonstrated monolithic integration of InP-based waveguide photodiodes (WGPDs) with metal-insulator-metal (MIM) capacitors using the 3-inch diameter wafer process. The uniformity of MIM capacitance and the dielectric breakdown voltage of the capacitor obtained within +/-2 % and over 100 V, respectively. The dark current of WGPDs was less than 3 nA at a reverse voltage of 1.6 V, owing to the InP passivation structure formed on WGPD surface. The fabricated integrated chip size was 2.0 mm × 5.1 mm. These results indicate that integrated WGPDs can provide both smaller and easier assembly for the compact coherent receiver.