FAULT POINT SEARCHING METHOD FOR OPTICAL AMPLIFICATION RELAY TRANSMISSION LINE AND OPTICAL AMPLIFIER

摘要

PURPOSE:To suppress the natural discharge light which is caused by the automatic gain control by branching partly the light received from a light reflection tester to connect the branch light to the line set in the opposite direction and then supplying the light to the gain part of an optical amplifier of the line. CONSTITUTION:The signal light received from a light reflection tester through an incoming transmission line 11 is amplified by a gain part 1 and compensated for its loss caused on the line 11. The amplified signal light passes through an isolator 3 and is branched by a photocoupler 5. Some of these branched light are inputted to the transmission line 13 with others inputted to a mirror 7 respectively. The light entered into the line 13 generates the dispersion beams and transmits them in the opposite direction through the line 13. Then these transmitted beams are branched by the photocoupler 5 and supplied to a down-transmission line 14 via a waveguide 9 and a photocoupler 6. Meanwhile the light branched toward the mirror 7 by the photocoupler 5 is reflected and branched again by the photocoupler 5. These branched beams are supplied to the line 14 via the waveguide 9 and the photocoupler 6. Thus not only the scattered beams but also some of the signal light received from the light reflection tester are supplied to the line 14, and the generation of the natural discharge light is suppressed.