Modulation method for measuring heterodyne characteristics of photodetectors

An intensity-modulation method is suggested for measuring the parameters of photodetectors operated under optical heterodyne conditions. It is shown that the operation of a photodetector recording modulated radiation does not differ from the heterodyne operation. A description is given of apparatus for measuring heterodyne characteristics of photodectors at a wavelength of 10.6 μ in the range of radiation modulation (beat) frequencies up to 2 GHz. The results of measurements of the conversion efficiency and threshold power of doped photoresistors are compared with calculated values.