| 摘要 |
PURPOSE:To stabilize S/N value of a laser oscillator by modulating the phase of a feedback light at random or modulating by a high frequency signal at high speed to always vary the phase of the feedback light, and dispersing and averaging noise energy of a laser oscillator generated by reflected light in a frequency manner. CONSTITUTION:The light emitted from a semiconductor 1 is focused by a lens 4, phase-modulated by a phase modulator 2, refocused by a lens 4, and then incident to the end of an optical fiber 3 after refocusing. If the light is reflected on the incident end of the light of the fiber 3, the surface of an optical system lens 4, the reflected light is fed back as the near end reflection to the oscillator 1, and when the feedback light phase becomes special value, the oscillator 1 generates strong noise. However, since forcible phase variation can be applied to the feedback light by the modulator 2, if the phase is varied by the high frequency signal 5, noise frequency can be shifted to high frequency side to eliminate the strong noise in a signal band. |
