Patent ID: 9160135
Filing Date: 2015-10-13
Classification: H01S,H04B,H04J

Abstract:
1. An optical amplifying apparatus that amplifies a wavelength-division multiplexed optical signal, comprising: an input section whereto the wavelength-division multiplexed optical signal is inputted; a laser light source that generates multimode laser light; a double-clad optical fiber having a cladding portion whereto the multimode laser light is inputted and a core portion doped with a rare-earth element whereto the wavelength-division multiplexed optical signal is inputted, the double-clad optical fiber amplifying optical signals of a plurality of wavelengths in the wavelength-division multiplexed optical signal by a stimulated emission by the multimode laser light; a gain equalizer that flattens a gain characteristic of the wavelength-division multiplexed optical signal that has been amplified by the double-clad optical fiber; an output section that outputs the amplified wavelength-division multiplexed optical signal; and a residual pump light attenuating section that attenuates a residual pump light outputted from the double-clad optical fiber, the residual pump light attenuating section being disposed in such a manner that the residual pump light of the multimode laser light which has propagated through the double-clad optical fiber is incident on the residual pump light attenuating section before being incident on an isolator, the residual pump light attenuating section including a residual pump light leakage portion that causes the residual pump light which has propagated through the cladding portion to leak out of the cladding portion, and a thermal conversion portion that converts a part of the leaked-out residual pump light into heat, a part of the residual pump light being outputted from the residual pump light attenuating section to be incident on the isolator.