| 摘要 |
PROBLEM TO BE SOLVED: To provide a light amplifier for conducting bedirectional amplification with a gain stabilizing optical fiber amplifier using light feedback as a base, with a simple constitution. SOLUTION: This light amplifier is provided with rare earth dorpant optical fibers 1a and 1b which are excited according to exciting lights from an exciting light source for amplifying signal lights and a feedbacking means for selectively feedbacking lights, in a wavelength band within an amplification band to the rare earth dorpant optical fibers 1a and 1b. Thus, optical circulators 6a and 6b with plural terminals are shared by light-amplifying parts in each direction, so that the number of parts can be reduced, and the constitution can be simplified, and excess loss can be reduced. |
