| 摘要 |
PURPOSE: To provide a fiber laser wherein, without the need for adjustment in the polarization state, a short light pulse can be generated. CONSTITUTION: First and second 45 degree Faraday rotators 56 and 60 are positioned near the first and second reflection mirrors 50 and 52 which form optical path, and the light ray from a polarizing beam splitter 76 is polarized by 45 deg. with the second 45 degree Faraday rotator 60, and through a single-mode fiber 74 and an Er-doped fiber 72, the optical ray reflected on the first reflection mirror 50 is changed in its polarizing state by -45 deg. with the first 45 degree Faraday rotator 56. Then reflected at the second 45 degree fiber rotator 60 again, the light ray is returned to an initial polarizing state again with the second 45 deg. Faraday rotator 60 in a path as the light ray is propagated in the direction from an amplifier 58 to a pulse generation promoting device 54, and the light ray passes through the polarizing beam splitter 76 for promoting passive mode draw-in with the pulse generation promoting device 54, so that a light pulse close to a pico second is generated. |
