Raman amplifier

摘要

A plurality of pump light sources generate plural variations of pump light having different frequencies. A modulation circuit intensity-modulates the plural variations of pump light in the predetermined periods, respectively. A pump light pair whose frequency difference equals a Raman shift frequency are modulated such that they cannot simultaneously enter an emission state. A wavelength-multiplexer wavelength-multiplexes the plural variations of pump light modulated by the modulation circuit. An optical guide device guides the plural variations of pump light wavelength-multiplexed by the wavelength-multiplexer to an optical fiber.