OPTICAL WAVEGUIDE, WAVEGUIDE TYPE OPTICAL AMPLIFIER HAVING IT, AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a fiber-optic amplifier the wavelength-to-gain characteristic of which is flattened in its amplification band by a new method. SOLUTION: This fiber-optic amplifier has a Gaussian wavelength-to-gain characteristic in its amplification band 111 and uses a thulium-doped optical fiber. This amplifier is made to have a flat amplification band 113 by adding an NH group having an absorption band 112 having the same center frequency as that of the amplification band 111 to the optical fiber.