Electro-thermal parameter extraction of avalanche photodiode using quasi-DC optical pulses [pulsed laser radar applications]

For pulsed laser radar applications, the accuracy of measured distance depends largely on the rise time of received pulses. Due to nonlinearity of the avalanche photodiode in its breakdown region, the rise time of avalanche response changes with incident peak optical pulses. An accurate model of the avalanche photodiode is needed to predict correctly the time of arrival of incident pulses. In this work, we describe one experiment-based method of characterization of avalanche photodiodes to predict electrothermal parameters when used with pulsed laser radar. We applied pulsed optical power of 5 /spl mu/s duration, 5% duty cycle, and measurement was carried out during the 'on' period so that reliable measurement is possible without affecting the device thermal time constants.