Measurement of nonlinear dispersive parameters of avalanche photodiode using pulsed RF signal and quasi-DC optical stimulus

In this work we report on a measurement system using pulsed RF signal and extracted results of nonlinear parameters of large signal dispersive model of avalanche photodiode. Nonlinear model of the avalanche photodiode (Si, SSO-AD-230, Silicon Sensor GmhH, Germany) was considered as two-port network and vector reflection measurement was carried out using Microwave Transition Analyzer (HP 70820A) in pulsed RF mode. Square wave optical stimulus of 5 )IS width (FWHM) and 5 kHz PRF (quasi-DC) were synchronized with the pulsed RF excitation using a synchronization circuit. Nonlinear parameters of large signal model of the avalanche photodiode were extracted from the small signal vector reflection measurement at different bias point and optical conditions. Thermal impedance of the device limits the CW measurement up to 0.1 mW of optical power, whereas using present method it was possible to characterize the device up to 1.3 mW of peak optical power.