Raman-Induced Asymmetric Pump Noise Transfer in Fiber-Optical Parametric Amplifiers

In this letter, a theoretical model accounting for the asymmetric transfer of pump noise in the gain spectrum of a single-pump fiber parametric amplifier due to the Raman effect is presented. The model is satisfactorily verified by the experiments. The experiments demonstrate that the pump electrical signal-to-noise ratio remains unchanged in contrast to the optical signal-to-noise ratio which decreases along the fiber.