Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Time-domain measurements of afterpulsing in InGaAs/InP SPAD gated with sub-nanosecond pulses



Alessandro Restelli, Joshua C. Bienfang, Alan L. Migdall


We experimentally investigate afterpulsing in an InGaAs single-photon avalanche diode (SPAD) operating in the biasing and sensing regime of periodic-gating techniques. These techniques support single-photon counting at rates in the 100 MHz range with low afterpulse probability and are characterized by sub-nanosecond active gates that limit total avalanche-charge flows to the 100-fC range or less. We achieve comparable gating and sensing performance with a system using non-periodic gates and are able to make traditional double-pulse afterpulse measurements from 4.8 ns to 2 s in this new low-avalanche-current regime. We find that with a 0.50-ns gate duration the per-gate afterpulse probability at 4.8 ns is 0.008, while with a 1.5-ns gate it is almost two orders of magnitude higher. We provide a quantitative connection between afterpulse probability and total avalanche charge, and between the performance observed in traditional gating techniques for InGaAs SPADs and those observed with periodic gating techniques.
Journal of Modern Optics


Optical instrumentation and technology, single photon detectors, avalanche photodiodes, near infrared.


Restelli, A. , Bienfang, J. and Migdall, A. (2012), Time-domain measurements of afterpulsing in InGaAs/InP SPAD gated with sub-nanosecond pulses, Journal of Modern Optics, [online], (Accessed May 28, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 28, 2012, Updated November 10, 2018