OPTICAL AMPLIFIER

摘要

PROBLEM TO BE SOLVED: To provide an optical amplifier which is increased in packaging density and is small in size and low on costs. SOLUTION: The light emitted from one exciting light source 1 is passed back and forth many times through a plurality of the optical amplifiers 4 and 7 by utilizing the fact that the exciting light loss within a semiconductor Raman optical amplifier is little, by which number of the exciting light source is decreased.