Design, implementation and testing of an integrated active quench circuit compatible with Geiger-mode APD arrays

An integrated active quench and reset circuit (AQRC) for accurately controlling the hold-off time in Geigermode avalanche photodiodes (GM-APDs) is designed. The circuit was fabricated using a conventional 0.15 μm CMOS process and evaluated using a packaged GM-APD. Experimental results show that the hold-off time can be precisely varied from nanoseconds to microseconds. This allows for selection of the optimal `afterpulse-free´ hold-off time for GM-APDs using digital inputs or additional signal processing circuits. Additionally, the APD is automatically reset following the end of the hold-off period, thus simplifying the control circuit. The circuit was also implemented for a 2 × 2 APD array. Results show that the hold-off time for individual APDs in the arrays can be accurately set via the circuit. The total layout area is about 130 μm × 200 μm using the 0.15 μm CMOS process. The layout area can be reduced further with smaller dimension CMOS processes opening up the possibilities for larger scale integrated photon counting arrays.