On the estimation of thermal resistance of laser diodes

A standard technique to evaluate the thermal resistance of laser diode is based on the temperature dependence of forward biased diode junction voltage. The device is pulsed biased and thermal resistance is estimated from the voltage drop across the junction at the falling edge of heating pulse. However, this technique may give rise to erroneous results due to circuit transients, which may arise due to sudden removal of heating current. In order to evaluate the thermal resistance more correctly, a methodology has been discussed in this paper that separates out this circuit transient from the temperature- induced decay and correctly evaluates DUT thermal resistance.