| 摘要 |
PROBLEM TO BE SOLVED: To optical restore the synchronization of optical line digital signals including a series of digital pulses moving in optical fiber circuits at a previous ly set iterative frequency by constituting a light clock signal including pulse trains having the same iterative frequency. SOLUTION: The tapped line signal parts are superposed on pumping radiation by a splitter 20, are supplied to the optical fiber 24 and are sent via a splitter 26 to a looped optical route 25. The presence of the line signals together with the pumping radiation generate the clone signal formed by an FWM phenomenon. The clone signal is suppressed by a filter 31 and is split by a splitter 33. Next, the length of the looped optical route 25 is adjusted. If the zero pulse of the clone signal coincides with one pulse of the line signal, the zero pulse of the alone signal turns to the one pulse at the time of the next circulation in the looped optical route 25. The signal of the one pulse train having the same iterative frequency as the iterative frequency of the line signal passes the looped route 25. |
