| 摘要 |
PURPOSE:To detect quickly a fault and a fault point of an optical fiber cable without a labor by connecting the outputs of an optical fiber locator for emitting repeatedly an optical pulse whose wavelength is different from wavelength of light used by an optical transmission terminal station, to one optical transmission terminal station side, and an optical filter of its optical transmission terminal station, to an optical fiber cable through an optical branching device. CONSTITUTION:An optical transmitting signal between optical transmission terminal stations 1, 2 is selected by optical filters 5, 6, and communication is executed. An optical fiber locator 8 accumulates an initial data obtained by measuring an initial state of an optical fiber cable 3, in an initial data memory 15, and sends out repeatedly an optical pulse of wavelength lambda2 to the optical fiber cable 3 through an optical branching device 7 from an optical pulse emitting part 9. A reflected wave reflected at a fault point of the optical fiber cable 3 of this optical pulse is received by a photodetector 10 through the optical branching device 7, converted to an electric signal, and thereafter, amplified by an amplifier 11, becomes a digital signal by an analog /digital converter 12, an S/N is improved by an adding and averaging circuit 13 and a processor 14, a result of measurement is derived, and it is compared with the initial data and decided by a comparing and deciding circuit. |
