| 摘要 |
PROBLEM TO BE SOLVED: To prevent any malfunction of a cutoff circuit in the optical amplifier due to the Raman excitation light. SOLUTION: Typical configuration is a method to insert an excitation light elimination filter in the frontend of an input light detector and a reflective light detector comprising an optical amplifier. This eliminates any residual components of the Raman excitation light transmitted from the downstream of the optical fiber transmission path as an example, then detects only the signal components for the cutoff operation. A threshold is changed for determination to perform the cutoff operation depending on on/off state of the excitation light. Alternatively, the Raman excitation light itself may be used for detection of the output release state. COPYRIGHT: (C)2007,JPO&INPIT |
