LIGHT GAIN EQUALIZER, OPTICAL AMPLIFIER USING THE SAME, AND WAVELENGTH DIVISION MULTIPLEXING TRANSMITTER

摘要

PROBLEM TO BE SOLVED: To provide a light gain equalizer which can compensate the gain dependency on wavelength of a fiber optic amplifier to an error of about 0.1 dB by utilizing an etalon filter, and can be manufactured easily and the transmittance of which has small polarization dependency. SOLUTION: A light gain equalizer is constituted in such a way that external light is outputted to the outside after the light is transmitted through a plurality of etalon filters 1 and at least one fiber grating 2 or dielectric multilayered film filter by cascade-arranging the filters 1 and fiber grating 2 or dielectric multilayered filter. The etalon filters 1 have sinusoidal wave loss characteristics of the same amplitude and period of the term obtained, by performing Fourier series expansion on a loss wavelength characteristic for flattening gain and at least one fiber grating 2, or dielectric multilayered film filter is made to compensate the ripple component which ramains as the difference between the loss wave length characteristic for flattening gain and the loss wavelength characteristics by the filters 1. An optical amplifier device is constituted by combining an optical amplifier with the light gain equalizer. A wavelength division multiplexing transmitter is constituted by using the optical amplifier device.