| 摘要 |
PURPOSE:To smooth a speckle in the optical fiber, and to decrease speckle noises by vibrating a board having one fourth wavelength by frequency higher than the modulation frequency of signals through the electrodes of both before and behind surfaces. CONSTITUTION:A lens 2 for coupling is mounted between the semiconductor laser 1 and the optical fiber 5. A polarized light board 3 is arranged so as to pass the rays of a field component parallel with a joining surface of the laser 1. The board 4 having one fourth wavelength, which consists of a transparent piezo-electric crystal, has the electrodes 4a on both before and behind surfaces, and is disposed so that an optical axis forms an angle of 45 deg. to a joining surface. An electric field is applied between the electrodes 4a because a high- frequency oscillation circuit 6 vibrates the wavelength borad 4. Accordingly, incident conditions such as phase at an incident angle of the fiber 5 of the rays of the laser 1 are changed periodically, and an interference condition in the fiber 5 and a position and a form of the speckle are altered. |
