Photon Number Resolving Detector At Telecommunication Wavelength.

A photon number resolving detector is a fundamental device for realizing quantum computing, to say nothing of improving quantum key distribution. It is considered possible to establish a multipurpose optical quantum computer by combining of a photon number resolving detector and non-classical light such as a single photon or squeezed light in a feedback system. We are developing a photon number resolving detector at the telecommunication wavelength of 1.5 μm, in which the attenuation ratio of optical fiber is minimum. We adopt a InGaAs pin photodiode and a GaAs JFET in a charge integration amplifier, that is cooled to 4.2 K to reduce thermal noise and leak current. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]