Nonclassical states of light in a nonlinear Michelson interferometer

Nonlinear quantum metrology schemes can lead to faster than Heisenberg-limited scalings for the measurement uncertainty. We study a Michelson interferometer embedded in Kerr medium [Phys. Rev. A 92, 022104 (2015)] that leads nonlinear, intensity dependent phase shifts corresponding relative changes lengths of its two arms. The Cram\'er-Rao bound on minimum achievable uncertainties is worked out and requirements, practice, saturate are investigated. choice input state light into readout strategy at output end discussed. ideal nonclassical states must be used found highly susceptible photon loss noise. identify optimal each noise level both resilient capable giving enhanced sensitivities discuss practical implementations interferometry scheme using such states.