Integrated photon counting gain and bias control system

This paper describes the integration of an automatic gain and bias control circuit for avalanche photodiodes with the Sensl PCMPLusX photon counting module. The combination is a self contained module with integrated sensor, power supply, cooling and full microprocessor control system. The sensors can be configured remotely via a PC enabling the user to optimize the sensor performance for a particular application. The system has four channels which can be configured either in photon counting mode or gain control mode. With the photon counting module enabled the user can optimize detector characteristics such as quantum efficiency, dark count, amplification and operating temperature for specific applications. With the gain control module enabled the system allows the user to program the sensor to a desired multiplication gain factor and the circuit to automatically adjust for fluctuations in supply voltage.