The Traveling Fringes Photoconductor Principle And Optimization

Optoelectronic processing of microwave signals' requires photodetectors with both high speed and high saturation level. The low optical saturation intensities of classical high-speed photodiodes limit the delivered microwave power to few tenths of microwatts" ', '. In order to increase the saturation level of microwave photodetectors, we have proposed an original application of the synchronous drift, in a photoconductor, of photogenerated carriers with a moving interference pattern', '. This traveling fringes photodetector (TFP) provides a large detection volume that could be suitable for efficient generation of microwave signals. In this paper, we discuss on the influence of contacts on the TFP performances. We also present experimental results obtained with an optimized forward bias p.i.n GaAs sample that shows a sensitivity of 1 A" at resonance.