Nonlinear interferometer based on two-port feedback nondegenerate optical parametric amplification.

In this paper, we propose a nonlinear interferometer based on two-port feedback nondegenerate optical parametric amplification (NITFPA), which employs two linear beam splitters to feed the two output beams of a nondegenerate optical parametric amplifier back to its input ports. By comparing the NITFPA with the SU(1,1) interferometer (SUI), which is another typical nonlinear interferometer, we demonstrate that the NITFPA has its unique advantages in the precision enhancement of the phase estimation. In addition, we demonstrate that the NITFPA is also advantageous over the SUI in the robustness against the losses. Such a NITFPA may find its potential applications in quantum metrology. • We propose a nonlinear interferometer based on two-port feedback nondegenerate optical parametric amplification (NITFPA), which cyclically utilizes the internal entanglement sources to boost the phase sensitive photon number inside the interferometer, with the help of the feedback structure. • Given the same sources of system, our NITFPA is able to boost the internal photon number of the interferometer, and thus makes the phase sensitivity of the NITFPA enhanced compared with the traditional SU(1,1) interferometer. • Considering the effect of losses, we found that NITFPA performs better in the robustness against the losses than SU(1,1). [ABSTRACT FROM AUTHOR]