Low-noise single-photon detection at wavelength 1.55 mu m

The photon-counting performance of commercially available InGaAs/InP avalanche photodiodes operated in Geiger mode was investigated at temperatures between 77 and 260 K. In particular, their noise equivalent power was measured to be 4 × 10-17 WHz-1/2 at 77 K. The implications of these results in the context of a quantum cryptography application are discussed.