OPTICAL AMPLIFICATION TRANSMISSION SYSTEM AND OPTICAL AMPLIFICATION REPEATER SYSTEM THEREOF

摘要

PROBLEM TO BE SOLVED: To enable a system to cope with asymmetric traffic quantity. SOLUTION: Signal light, containing control command light controlling an exciting light distribution rate, is inputted from a transmission optical fiber 18-1 to an optical amplification fiber 30 and it is optically amplified. The output light of the optical amplification fiber 30 passes through an optical isolator 32 with low loss. Control command light outputted from the optical isolator 32 is inputted to a control circuit 44 through a monitor coupler 42. The control circuit 44 generates an excitation power control voltage signal from control command light. Output laser light beams of laser diodes 46 and 48 are inputted to the two inputs of an exciting light multiplexer/demultiplexer 50. The exciting light multiplexer/demultiplexer 50 multiplexes two laser inputs and divides it into two at a distribution rate following the exciting power control voltage signal from the control circuit 44. The two divided laser light beams are applied to the optical amplification fibers 30 and 36 through WDM couplers 34 and 40 as an excitation light.