High-efficiency uni-travelling-carrier photomixer at 1.55 μm and spectroscopy application up to 1.4 THz

The fabrication of InGaAs/InP uni-travelling-carrier photodiodes integrated with broadband horn antennas and demonstration of photomixing up to 1.8THz are reported. A radiated power of 1.1 mu W at 940 GHz was measured for a photocurrent of only 2.75 mA (50 mW optical power), demonstrating the high efficiency of the device. The conversion efficiency obtained has been increased by more than a decade compared to the best reported values in the literature. The photomixer is used to identify the 1411 GHz water vapour absorption line at atmospheric pressure.