Single-photon detection beyond 1 micro m: performance of commercially available inGaAs/InP detectors

Commercially available InGaAs/InP avalanche photodiodes, designed for optical receivers and range finders, can be operated biased above the breakdown voltage, achieving single-photon sensitivity. We describe in detail how to select the device for photon-counting applications among commercial samples. Because of the high dark-counting rate the detector must be cooled to below 100 K and operated in a gated mode. We achieved a noise equivalent power of 3 x [10.sup.-16] W/[Hz.sup.1/2] to a 1.55-[[micro]meter] wavelength and a time resolution well below 1 ns with a best value of 200-ps FWHM. Finally we compare these figures with the performance of state-of-the-art detectors in the near IR, and we highlight the potentials of properly designed InGaAs/InP avalanche photodiodes in single-photon detection. Key words: Photon counting, photon timing, avalanche photodiodes, single-photon detection, InGaAs/InP detectors.