A controller (110) for controlling the reverse-bias voltage of an avalanche photodiode in a transceiver or receiver. The controller (110) includes memory (120, 122, 128) for storing information related to the avalanche photodiode, and analog to digital conversion circuitry (124, 127) for receiving an analog signal corresponding to the temperature of the avalanche photodiode, converting the received analog signal into a digital value, and storing the digital value in a predefined location within the memory (128). Control circuitry (134) in the controller controls the operation of the avalanche photodiode in accordance with the digital value corresponding to the temperature of the avalanche photodiode and a temperature lookup table (122) stored in the memory. A serial interface (121) is provided to enable a host device to read from and write to locations within the memory. The invention is also implemented as a method for controlling the reverse-bias voltage of an avalanche photodiode in a transceiver or receiver and a method for calibrating a transceiver or receiver having an avalanche photodiode.