Pulse response characterization of the mid-infrared photodetectors in nonlinear vector network analyzer system (Conference Presentation)

We describe a new system for broadband characterization of mid-infrared (MIR) photodetectors, manufactured by the VIGO System and encapsulated in TO-8 can. The system comprises a high repetition rate pulsed quantum cascade laser source, stimulating a detector in a special test fixture that is connected to ports of a vector network analyzer (VNA) with a pair of cables. The system operates in a mode of nonlinear VNA, i.e. it is capable of measuring magnitude and phase spectra of harmonic signals up to 5 GHz of bandwidth. This approach enables recovering sub-nanosecond differential pulses of amplitudes below 1 mV and speed up performance evaluation of MIR detectors tested.