OPTICAL MULTIPLEXER/DEMULTIPLEXER AND OPTICAL FIBER AMPLIFIER

摘要

PURPOSE:To obtain an optical fiber amplifier of a bidirectional excitation type which decreases light losses and can be miniaturized. CONSTITUTION:A exciting light source 52 is coupled to a terminal #1 of an optical multiplexer/demultiplexer 50 consisting of two sheets of optical filters for demultiplexing and multiplexing and the exciting light therefrom is made incident. The signal light from an input terminal is made incident on the terminal #2 of the optical mutiplexer/demultiplexer 50. Both ends of a fiber 5 for optical amplification added with a rare earth element are connected to the terminals #3, #4 of the optical multiplexer/demultiplexer 50. The signal light which is reflected by the optical fiber for multiplexing and is passed through the optical filer for demultiplexing is made incident from the one terminal #3 of the fiber 54 for optical amplification. The exciting light branched to about 1/2 by the optical filter for demultiplexing after passing through the optical filter for multiplexing is made incident from the two terminals #3, #4 of the fiber 54 for optical amplification. The signal light amplified by the fiber 54 for optical amplification is outputted through the terminal #4, the optical filter for demultiplexing and the terminal #5 to an output end.