| 摘要 |
PURPOSE:To prevent the production of an interference pattern by selecting core diameter and refractive index difference and selecting the material of a clad layer to have the absorption coefficient equal to and higher than the specific value, thereby accurately enabling to control the beam pattern in the prescribed shape. CONSTITUTION:A single mode optical fiber 3 of short size with extremely large transmission loss of a clad layer is mounted on the end face, from which the laser light of a semiconductor laser element is emitted. An optical fiber 3 is secured to a stem 2, but a V-shaped groove 4 is cut to facilitate positioning of the fiber 3 which is secured to the stem 2. The fiber 3 is mounted on the groove 4. A laser light from the laser 1 which is coupled to the fiber 3 is produced through a cap 6 which is mounted on a glass window 5. The optical fiber has transmission loss equal to and higher than 1cm<-1> for the laser light wavelength using the material of the clad layer, and core diameter and refractive index difference are selected so as to transmit only a single mode. |
