OPTICAL AMPLIFIER

PROBLEM TO BE SOLVED: To provide at a low cost an optical amplifier, detecting noise optical power, signal optical power or the like, generated upon amplifying a signal light, through a simple optical circuit structure with a high accuracy, and stably acquiring WDM (Wavelength Division Multiplex) light having flat wavelength characteristic. SOLUTION: The optical amplifier is equipped with: a light amplifying circuit 1 which amplifies signal light; a light reflecting medium arranged on an optical fiber F connected to the light amplifying circuit 1 and employing a tilt chirp type fiber grating having a transmission wavelength characteristic for flattening the gain wavelength characteristic of the optical amplifying circuit 1; a light receiver 3 which receives light of signal band reflected by the light reflecting medium to detect power; an operation circuit 4 which obtians the wavelength characteristic of the WDM light transmitted through the light reflecting medium based on the detecting result of the light receiver 3; and a control circuit 7 which controls the light amplifying circuit 1, based on the wavelength characteristic of the WDM light. COPYRIGHT: (C)2010,JPO&INPIT