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Single-photon detector operates at telecom wavelengths

08 Nov 2007

A Chinese research team has demonstrated an integral gated-mode single-photon detector that monitors the charge number of an avalanche pulse rather than the peak current.

Avalanche photodiodes (APD) are commonly used in single-photon detectors (SPDs) for quantum cryptography techniques. Currently, the most effective performance mode for APDs is gated-mode operation. Although this method works well, the use of short-gate pulses leads to the production of two transient spikes that obscure the photon-induced avalanche pulses.

The researchers describe the design and fabrication of an integral gated-mode single-photon detector (IGSPD) in which the transient spikes in conventional gated-mode operation are cancelled completely by integrating. This allows improved performance of a single photon detector while using the same avalanche photodiode (J. Phys. D: Appl. Phys. 40 6922).

The team has demonstrated that at telecom wavelengths the system achieves a detection efficiency of 29.9% at a dark count probability per gate equal to 5.57x10−6/gate (1.11 × 10−6 ns−1) at 1550 nm.

The developed IGSPD shows improved performance over traditional gated mode SPDs, and is expected to be helpful in future device design.

AltechnaSPECTROGON ABNIL TechnologyPhoton Engineering, LLCDelta Optical Thin Film A/SAUREA TECHNOLOGYLBP Optics Ltd
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