| 摘要 |
PURPOSE:To attain constitution without waste as a redundant system by duplicating only effective parts suppressing the deterioration in the operating rate and not duplicating an optical transmission circuit with less fault rate. CONSTITUTION:The optical transmission system in which one optical fiber line is adopted to apply simultaneous transmission in two way of incoming and outgoing directions is used, and one terminal of an active optical fiber line 32 and an active light emitting element 14a and an active photodetector 25a are coupled via an active optical coupler 31, and one terminal of a standby optical fiber line 34, a standby light emitting element 14b and a standby photodetector 25b are coupled via a standby optical coupler 33. An output of a transmission use optical transmission line 13 is selectively fed to the active light emitting element 14a and the standby light emitting element 14b by a transmission relay 28, and an output of the active photodetector 25a and an output of the standby photodetector 25b are selected and inputted to a reception use optical transmission line 2b by a reception relay 29. Since the optical transmission circuit with a low inoperation rate (fault rate) is not in duplicate, the cost of the part is not wasted. |
