Theoretical Analysis of the Polarization- and Frequency-Dependent Gain for Fiber Optical Parametric Amplifier

We develop the gain expression of fiber optical parametric amplifier with birefringent effect and loss. The simulations show that the optical parametric amplifiers' gain is frequency-dependent and polarization-dependent. If the signal polarization state goes along the fast axis, when the average half-difference of two pump frequencies is smaller the gain flatness is better; if the signal polarization state goes along the slow axis, when half-difference of two pump frequencies is smaller the gait? flatness is worse, and the gain bandwidth becomes wider We still find that the signal gain is different under the distinct signal polarization state.