| 摘要 |
PURPOSE:To simplify an oscillation mode to a stable vertical one by a method wherein at least a part of the radiated laser light from a semiconductor laser is fed back as a return light from an optical element having reflection function provided outside to the laser, the center of laser light emitting position and the center of return light position on a laser resonation end surface are not made coincident but made to close to each other. CONSTITUTION:The laser light 43 radiated from the light emitting position 42 existent in one side resonator end surface 41 of the semiconductor laser 40 is collimated by means of a lens 44, and a light 45 becoming parallel is reflected on a flat mirror 46. At this time, the flat mirror 46 is so set that the optical axis 47 of the laser 40 parallel with the light 45 does not parallel with a reflected light 48, and the reflected light 48 is converged by means of the lens 44 into a light 49, and then brought to image formation at a position 50 different from the light emitting position 42 on the resonator end surface 41. Thus, the return light is fed back, and then a light source which has no reflection noise and has extremely stable vertical single mode oscillation spectrum is obtained. In order to change into a module, the radiated light 52 from the other resonator end surface 51 is coupled with a fiber 53. |
