Space qualified four channel Si SPAD detector

We report on the development and performance of a continuous operation four channel silicon Single-Photon Avalanche Diode (SPAD) detector, which is based on the K14 design that has a long and successful history of deployment in space missions. The four channel design makes this detector attractive for applications in quantum communication, particularly ones facilitated via satellites. Overall, this detector is uniquely suited for missions in space, which comes not only because of its radiation ruggedness, low mass and power consumption, but importantly also, because it is capable of stable operation in temperature range from -55 to +50 °C using only passive compensation. Specifically, this new detector package integrates four independent K14 SPADs, each with a 25 µm active area, and each SPAD is equipped with separate active quenching circuit that allows for operation at excess bias voltage ranging from 0,5 to 2,5 V above breakdown. Moreover, the detector package has integrated voltage converter, which generates and regulates identical bias voltage for all channels. At 2 V above breakdown the detector possesses roughly 36% detection probability for wavelength range of 500 to 800 nm and timing resolution better than 40 ps RMS. A new advancement in the detector’s design is an increase in its maximum detection rate of up to 3 MHz, a 50% improvement over its predecessor. Additionally, we have recently achieved a modest reduction in DCR, a reduction in power consumption and simplification of the detector’s connections.