Uni-traveling-carrier photodiodes

A photodiode (PD) that can provide both high speed and high saturation output is of great importance for the development of future large-capacity fiber-optic communication systems and ultrafast measurement systems. A high output PD combined with an erbium-doped fiber amplifier can eliminate the need for a broadband electronic post-amplifier and thus enables us to construct photoreceivers with a much faster response. We recently developed a uni-traveling-carrier photodiode (UTCPD) that satisfies these requirements. We describe the characteristic features and photoresponse performance of the InP/InGaAs UTC-PD, and outline its application to fiber-optic communication systems.