| 摘要 |
PURPOSE:To obtain an excellent coupling device with low noise by a method wherein a vibrator made of transparent piezo electric single crystal and a coupling lens are disposed between a semiconductor laser and an optical fiber. CONSTITUTION:A vibrator 3 made of transparent piezo electric single crystal which has a transparent electrode 3a is inserted between a semiconductor laser 1 and an optical fiber 4, and a laser light is coupled with the optical fiber 4 by means of a lens 2. By an oscillating circuit connected 3a, 3b and swinged at a proper frequency, incident condition such as phase or the like is varied periodically on an incident surface of the optical fiber 4, interference condition is varied in the fiber 4, and the position and magnitude of a mottled pattern called speckle are varied. Accordingly, when oscillated with higher frequency than a modulating frequency for a signal, a position of a speckle is smoothed, and a noise can be reduced, and a frequency component of the vibrator can be removed by an LPF at a receiving end. |
