| 摘要 |
PURPOSE:To reduce occurrence of both the signal distortion and the noise, by connecting the optical fiber bundle of a fixed length to the light source having the laser diode LD so that the contrast ratio of the speckle pattern is set to a prescribed value or less. CONSTITUTION:Light emitting part 10 consists of LD100, optical fiber bundle 15 of a fixed length which has no connecting point to LD100, and optical connector 20 each. The photosignal sent from part 10 is led to light receiving part 50 via transmitting optical fiber 30 and connecting optical connector 40 each. Then bundle 15 is set to the prescribed length by which the contrast ratio of the speckle pattern is reduced less than the prescribed value. As a result, both the mode noise and the perturbation noise can be reduced, thus reducing both the amplitude distortion and the noise. |
