Abstract: Existing photodiodes in an optical component used for monitoring input light levels are used to measure the internal temperature of the optical component. Electrical measurements are taken across the photodiode while it is slightly forward biased, and the approximate temperature is determined according to pre-measured current-voltage characteristics of the optical component calibrated at different temperatures. By adjusting its parameters to compensate for the temperature, the performance of the optical component can be optimized. An external microprocessor system controls biasing of the photodiode, electrical measurement of the photodiode, and determination of the optical component temperature.