MONITORING SYSTEM AND STABILIZING SYSTEM FOR OPTICAL-FIBER ACTIVE TRANSMISSION PATH

摘要

PURPOSE:To stabilize the loss compensation in an optical-fiber active transmission path by inputting testing light having the central wavelength which is located in the band of Raman amplification and is different from the central wavelength of a signal light into the optical-fiber active transmission path, taking out the backward scattering light, and observing the loss distribution in the longitudinal direction. CONSTITUTION:Pumping light beams are inputted into an optical-fiber active transmission path 11 wherein signal light is transmitted from pumping light sources 13f and 13b through light synthesizers 151 and 152. The loss in the optical fiber is compensated by Raman amplification. A pulse tester 17 inputs testing light having the central wavelength which is located in the band of the Raman amplification and is different from the central wavelength of the signal light into the optical-fiber active transmission path 11 through a light synthesizing and splitting device 19. The intensity of the backward scattering light is observed on the time axis. Thus, the loss distribution in the longitudinal direction in the optical-fiber active transmission path 11 can be monitored. In this way, the loss compensation in the optical-fiber active transmission path 11 can be stabilized.