New photodetector with cascaded waveguide photodiodes and resonant electrode structures for millimeter-wave subcarrier optical fiber link system

This paper presents a new photodetector operating at millimeter-wave range. The waveguide photodetector structure and a brief principle of the electrode design are described in this paper. By taking the advantages of narrow band operation in millimeter-wave subcarrier optic fiber link system, the proposed photodetector is designed to have cascaded resonant structures and a reflector to achieve high RF output. Resonators and reflector are realized by using one-fourth wavelength shorted stubs and an open stubs of coplanar waveguide, respectively. Velocity matching between optical waves and detected millimeter wave signals are performed by introducing an S-shaped meandering transmission line for the photocurrents.