| 摘要 |
PURPOSE:To remove the effect of reflected light and perform stable laser oscillation by so forming a serration to a lens or optical fiber as to give a phase difference to the half of coherent light thereby performing photo coupling. CONSTITUTION:This is photo coupler constituted by a semiconductor laser 1, optical fibers 3, 5 and lenses 4, 2, wherein a serration D whose upper half and lower half are lambda/4 is formed to the lens 4 or optical fiber 5. (lambda is the wavelength of the output light of the semiconductor laser 1.) Hence, the light entered from the semiconductor laser 1 via lenses 4, 2 to the semiconductor lasers 3, 5 becomes of a phase difference of lambda/4 in the upper and lower halves and the reflected light thereof become lambda/2 in the upper and lower halves, resulting in that they mutually negate. Hence, the effect that the reflected light gives to the operation of the semiconductor laser 1 may be eliminated. |
