HIGH-POWER HIGH-FREQUENCY TRAVELING-WAVE HETEROJUNCTION PHOTOTRANSISTORS WITH INTEGRATED POLYIMIDE WAVE-GUIDE

A high-power high-speed phototransistor has been demonstrated using a traveling-wave (TW) structure with an integrated polyimide optical wav eguide, In our configuration, optical power transfer is distributed al ong the length of the device via leaky mode coupling of light from the polyimide waveguide to the active region of the phototransistor. The TW electrode design allows for an electrically long structure while ma intaining high bandwidths. Due to the increased absorption volume, the optical power handling capabilities of the TW-heterojunction phototra nsistors (TW-HPT's) are improved over that of conventional lumped-elem ent HPT detectors. The experimental results show no saturation of the fundamental at 60 GHz up to 50 mA of dc photocurrent.