PROCEEDINGS ARTICLE | February 4, 2013
Proc. SPIE. 8631, Quantum Sensing and Nanophotonic Devices X
KEYWORDS: Human-machine interfaces, Photodetectors, Sensors, Calibration, Single photon, Field programmable gate arrays, Control systems, Head, Picosecond phenomena, Multiplexers
We present a photon-counting module based on InGaAs/InP SPAD (Single-Photon Avalanche Diode) for detecting
single photons up to 1.7 μm. The module exploits a novel architecture for generating and calibrating the gate width,
along with other functions (such as module supervision, counting and processing of detected photons, etc.). The gate
width, i.e. the time interval when the SPAD is ON, is user-programmable in the range from 500 ps to 1.5 μs, by means of
two different delay generation methods implemented with an FPGA (Field-Programmable Gate Array). In order to
compensate chip-to-chip delay variation, an auto-calibration circuit picks out a combination of delays in order to match
at best the selected gate width. The InGaAs/InP module accepts asynchronous and aperiodic signals and introduces very
low timing jitter. Moreover the photon counting module provides other new features like a microprocessor for system
supervision, a touch-screen for local user interface, and an Ethernet link for smart remote control. Thanks to the fullyprogrammable
and configurable architecture, the overall instrument provides high system flexibility and can easily
match all requirements set by many different applications requiring single photon-level sensitivity in the near infrared
with very low photon timing jitter.
