| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical amplifier which can collectively amplify wavelength-multiplex signal lights of >=3 wavelength channels having arbitrary propagation directions. SOLUTION: The optical amplifier is equipped with a small number of optical amplifying means less than the wavelength channels for signal lights propagated over >=3 wavelength channels having the propagation directions set by the wavelength channels in the same coated optical fiber and an optical isolator means which optically branch and couple signal lights of the respective wavelength channels and isolate them in the propagation directions before or/and behind the optical amplifying means. The optical isolator circuit used for it is constituted by mutually connecting input/output ports corresponding to the same wavelength channel on the side where waveguides are branched by the wavelength channels of two 1:N branch type optical wavelength multiplexing and demultiplexing circuit and arranging the optical isolators on the waveguides corresponding to the wavelength channels. |
