Emission characteristics of ion-irradiated In(0.53)Ga(0.47)As based photoconductive antennas excited at 1.55 microm.

We present a detailed study of the effect of the carrier lifetime on the terahertz signal characteristics emitted by Br(+)-irradiated In(0.53)Ga(0.47)As photoconductive antennas excited by 1550 nm wavelength femtosecond optical pulses. The temporal waveforms and the average radiated powers for various carrier lifetimes are experimentally analyzed and compared to predictions of analytical models of charge transport. Improvements in bandwidth and in average power of the emitted terahertz radiation are observed with the decrease of the carrier lifetime on the emitter. The power radiated by ion-irradiated In(0.53)Ga(0.47)As photoconductive antennas excited by 1550 nm wavelength optical pulses is measured to be 0.8 muW. This value is comparable with or greater than that emitted by similar low temperature grown GaAs photoconductive antennas excited by 780 nm wavelength optical pulses.

Photomixing at 1.55 microm in ion-irradiated In(0.53)Ga(0.47)As on InP.

We report the first demonstration of a terahertz photomixer made of ion-irradiated In(0.53)Ga(0.47)As lattice-matched to InP and fiber-optic coupled with the drive lasers. A continuous-wave radiation is generated at frequencies up to 0.8 THz by photomixing two continuous-wave laser diodes around 1.55 microm. The measured 3dB-down bandwidth of 300 GHz yields a carrier lifetime of 0.53 ps, in agreement with the value of 0.41 ps measured in pump probe experiments. The detected signal is at the most 15 dB lower than the one obtained from similar photomixers fabricated from low-temperature-grown GaAs.