| 摘要 |
PURPOSE:To reduce the size and cost of a light amplifier by forming one light isolator in such a manner so as to serve as two light isolators. CONSTITUTION:Input signal light 2 from an input port 1 is multiplexed with excitation light 4 from an excitation light source 3 by a light synthesizing device 5 to enter the first light beam connection system of a light isolator 6. Light which passes through the light isolator 6 and is emitted from the first light beam connecting system is guided to an erbium doped fiber 7, and the signal light is light-amplified here. The light-amplified signal light is again entered in the second beam connection system of the light isolator 6 to be output to an output port 8 through the light isolator 6. In this case, the light isolator 6 acts in same manner as two light isolators in the case where the light isolators are respectively inserted in the input side and output side of the erbium doped fiber 7. Thus, expensive light isolators are reduced to one, the reduction of cost of a light amplifier can be achieved, and the space saving can be accomplished. |
