Patent ID: 6137932
Filing Date: 2000-10-24
Classification: G02B,H01S,H04B

Abstract:
An apparatus for controlling gain of an optical fiber amplifier which includes a plurality of optical isolators, an excitation light source, a wavelength division optical fiber coupler and a special optical fiber, wherein at least one of said optical isolators is disposed at both input and output ports of said optical fiber amplifier so that an input signal light can propagate in one direction; said wavelength division optical fiber coupler couples excitation light from said excitation light source to the input signal light or separates one of the excitation light and the input signal light from the other; and said special optical fiber is disposed between said optical isolators so as to transfer energy of the excitation light to the input signal light, said apparatus comprising:at least one optical fiber grating disposed between said special optical fiber and each of said optical isolators, said optical fiber gratings serving as a resonator which oscillates at a predetermined wavelength; andtuning means for tuning a center reflection wavelength detuning between said optical fiber gratings to control said gain of said optical fiber amplifier to have a desired value.