Zero-bias high-speed and high-output-voltage operationof cascade-twin unitravelling-carrier photodiode

A novel cascade-twin unitravelling-carrier photodiode (UTC-PD), which is suitable for zero-bias high-speed and high-output-voltage operation, is achieved by monolithically integrating two UTC-PDs and a 3 dB optical beam splitter. Under zero-bias conditions, the fabricated device exhibits high output voltages of 0.75, 0.5 and 0.25 V with 3 dB bandwidths of 20, 40 and 60 GHz, respectively.