Improving phase sensitivity of a hybrid interferometer with the two-mode squeezed coherent state

Abstract

We investigate the enhancement of phase sensitivity of a nonlinear-
linear hybrid interferometer with the input of the two-mode squeezed coherent state
(TMSCS). With the TMSCS produced by four-wave mixing, the quantum Cram er-
Rao bounds (QCRB) can beat the Heisenberg limit (HL). Under the phase matched
conditions, the optimal phase sensitivity with the balanced homodyne detection
measurement can beat the HL and approach QCRB. The e ects of internal and external
losses on the measurement accuracy are also discussed. The results demonstrate that
the scheme is robustness against to internal losses and this protocol can resist external
detection loss which is up to 39%. Our results improve the performance of hybrid
interferometers and this scheme can nd important practical applications in quantum
metrology.