The phase-sensitivity of a Mach-Zehnder interferometer for the Fock state inputs

Abstract

Phase-sensitivity of some different measurement schemes with a Mach-Zehnder interferometer is studied. The input light is considered to be in a photon number state and the detectors are assumed to be ideal with quantum efficiency of unity. Direct calculation of the operators corresponding to the measurement schemes shows that the uncertainty of the phase-shift measurement can be reduced to the Heisenberg limit of 1/N (N is the total number of the photons in the input state) with certain measurement schemes. (C) 1998 Elsevier Science B.V. All rights reserved.