The id400 single-photon-detection module released by id Quantique SA has a detection head that contains a cooled InGaAsP/InP avalanche photodiode (APD) optimized for 1064-nm single-photon detection and a fast sensing and quenching electronic circuit. The control unit provides APD temperature control and regulation, power supply, gate generation and dead-time settings from 0 to 100 μs. It also provides connectors for input/output signals and a USB interface for Labview communication. The device operates in free-running and internal or external gating modes. Gate width is adjustable from 500 ps to 1 μs in 100-ps increments. Internal gating frequency is adjustable from 1 Hz to 10 MHz, and the delay is adjustable from 500 ps to 1 μs in increments of 10 ps.