Design of a hold-off time control circuit for geiger-mode avalanche photodiodes

Abstract

A high-resolution hold-off time control circuit for Geiger-mode avalanche photodiodes (GM-APDs) that enables linear changes to the hold-off time from several nanoseconds to microseconds is presented. The resolution of the hold-off time can be varied from nanoseconds to tens of nanoseconds with a range up to microseconds to cater for a variety of GM-APDs. This circuit allows setting of the optimal 'afterpulse-free' hold-off time for any GM-APD through digital inputs or additional signal processing circuitry. With this circuit, the APD is automatically reset following the end of the hold-off period that further simplifies the end-user’s control. A layout of this circuit is designed using a conventional 0.15 μm complementary metal oxide semiconductor (CMOS) process, resulting a area of 95 μm × 55 μm which makes it suitable for use with APD arrays.