| 摘要 |
PURPOSE:To optimize reflected noises, by providing a polarization beam splitter and a mirror in an outer cavity of a semiconductor laser, splitting only a TM mode wave from laser light, returning the wave to the semiconductor laser, and reducing the width of the laser light beam. CONSTITUTION:A polarization beam splitter PBS splits laser light, which is emitted from a semiconductor laser LD into a TE mode wave and a TM mode wave. The TE mode wave is inputted to an optical fiber OF through the splitter PBS intactly and through an isolator IS. The TM mode wave is reflected by a mirror MR and returned to the semiconductor laser LD again through the splitter PBS. Then, fluctuation in number of electrons and fluctuation in energy of electrons in the oscillating state are suppressed without increasing the reflection noises of the TE mode wave, which governs the strength of oscillation. Thus, the width of the laser light beam is decreased, and the reflection noises are optimized. |
