Modelling of phase-sensitive two-pump fiber optical parametric amplifiers: a comparative study

Fiber optical parametric amplifiers (FOPAs) are versatile devices for various applications, such as efficient signal amplification over a wide gain bandwidth. In this paper, at first, by proposing a physical model based on the coupled amplitude equations, we first examine the effect of input relative phase on the gain spectrum of two-pump (2P) FOPAs. Then, we simulate the pump and signal evolutions along the optical fiber and compare 2P-FOPAs in phase-sensitive (PS) and phase-insensitive (PI) operation modes. The results show that the gain level and the gain smoothness of a PS-2P FOPA can be higher than those of a PI-2P FOPA if an appropriate relative phase is set at the fiber input. Moreover, phase-sensitive amplification allows for amplification with a lower noise figure than what quantum mechanics normally dictates. These results have novel applications in fiber-optic communication systems, enabling the amplification of signals with high gain and simultaneously minimizing the noise figure.