METHOD FOR TRANSMITTING LOW FREQUENCY SIGNAL IN OPTICAL FIBER COMMUNICATION LINE, METHOD FOR SUPPLYING PUMPING OPTICAL RADIATION TO ACTIVE CORE OPTICAL FIBER OF OPTICAL AMPLIFIER, METHOD FOR TRANSMITTING LOW FREQUENCY SIGNAL TO OPTICAL AMPLIFIER AND OPTICAL AMPLIFIER

摘要

PROBLEM TO BE SOLVED: To improve the reliability and efficiency of a line by optically connecting the end face of an active core optical fiber part to optical fibers of 1st and 2nd cables, connecting a 1st pumping optical radiation source to one of two end faces of the active cove optical fiber part and making at least one of the end faces of an optical fiber communication line to perform low frequency modulation of optical radiation for signal transmission. SOLUTION: A coupler 18 that resembles a coupler 17 well is connected to a photodiode 28 through an end face of an optical fiber length part and its other end is connected to a laser 20. Further, the photodiodes 27 and 28 connected to the couplers 17 and 18 are connected to a microprocessor circuit 29 and various circuits that are related to the lasers 19 and 20 are connected to the microprocessor circuit 29 in the same way. When the laser 29 operates, an amplifier outputs a signal VC that is a function of the intensity of pumping optical radiation where the intensity appears on an output of a dichroic coupler 17 through an edge part 26 and sends the signal to the circuit 29.