Power law temporal dependence of InGaAs/InP SPAD afterpulsing

Abstract

The characterization and analysis of afterpulsing behavior in InGaAs/InP single photon avalanche diodes (SPADs) is reported for gating frequencies between 10 and 50 MHz. Gating in this frequency range was accomplished using a matched delay line technique to achieve parasitic transient cancellation, and FPGA-based data acquisition firmware was implemented to provide an efficient, flexible multiple-gate sequencing methodology for obtaining the dependence of afterpulse probability P _ap on hold-off time T _ho. We show that the detrapping times extracted from the canonical exponential fitting of P _ap(T _ho) have no physical significance, and we propose an alternative description of the measured data, which is accurately fit with the simple power law behavior P _ap ∝  with α ∼ 1.2 ± 0.2. We discuss the physical implications of this functional form, including what it may indicate about trap defect distributions and other possible origins of this power law behavior.

Keywords:

• single photon avalanche diode
• SPAD
• photon counting
• Geiger mode
• InGaAs/InP
• afterpulsing

Acknowledgements

We are grateful to Alessandro Restelli, Josh Bienfang, Joe Campbell, Naota Namekata, and Massimo Ghioni for providing us with raw data from afterpulsing measurements made in their respective laboratories to analyze for this study. We also thank Prof. Ghioni for insightful discussions concerning afterpulsing in silicon SPADs.