| 摘要 |
PROBLEM TO BE SOLVED: To stably control the light frequency of a transmission laser even when light frequency reference light is interrupted. SOLUTION: An optical shutter 44 is normally opened and light frequency reference light from an optical network is inputted to an injection synchronizing laser device 42. An optical multiplexer 46 multiplexes the outputs of the laser device 42 and transmission laser devices 40-1 to 3 and a light frequency discriminating equipment sweeps the output light of the multiplexer 46. The photoelectric conversion output of a photodetector 52 is impressed on a controller 50. The controller 50 adjusts and controls the driving current of the laser devices 40-1 to 3, etc., so as to permit the output light frequencies of the laser devices 40-1 to 3 to be a desired value. The controller 50 also temporarily close the optical shutter 44 and adjusts the driving current of the laser device 42, etc., so as to permit the light frequency of the output light of the laser device 42 at that time to coincide with that when the optical shutter 44 is opened. |
