Characterization of sub-THz photonic-transmitters based on CaAs-AlGaAs uni-traveling-carrier photodiodes and substrate-removed broadband antennas for impulse-radio communication

Abstract

A novel photonic transmitter for wireless terahertz (THz) impulse-radio (IR) communication is realized by monolithic integration of a GaAs-AlGaAs-based uni-traveling-carrier (UTC) photodiode with a substrate-removed broadband antenna. The device can radiate strong sub-THz pulses (20-mW peak-power) with a narrow pulsewidth (< 2 ps) and wide bandwidth (100 similar to 250 GHz). The maximum average power emitted by our device, under the same THz time-domain spectroscopic setup, is around ten times higher than that of the low-temperature-grown GaAs-based photoconductive antenna, while with a much lower dc bias (9 versus 35 V). The bias-dependent peak output powers of our devices suggest their suitability for application as a data modulator/emitter for photonic THz IR communication.