High-Optical-Power, Wideband Distributed Photodetectors for Optical RF Interconnects

We propose, in this Phase I program, to study the feasibility of InP-based Velocity Matched Distributed Photodetectors (VMDP) for operation at 1.55 ¿m wavelength. The VMDP offers the possibility of high-power (100 mW), Wide bandwidth (up to 100 GHz) operation by combining the outputs of many photodetector elements along a transmission line. The basic concept has been demonstrated for the GaAs-based system for operation at 860 nm using MSM detector elements and e-beam lithography. We will investigate the adaptation to the InP-based system and the use of Schottky photodetector elements that do not require e-beam lithography to reach 100 GHz speeds. The approach is to design, model, and fabricate a series of test structures that allow the optical waveguide, electrical transmission line, photodetector, and integration challenges to be fully assessed. A successful program will provide sufficient data to evaluate feasibility of the InP-based VMDP structure, compare the MSM and Schottky diode approaches, and plan a technology development program for Phase II.