| 摘要 |
PURPOSE:To prevent reflected light from being back to a semiconductor laser by guiding the projection light from the semiconductor laser of an optical isolator which includes a lens for beam conversion, etc., slantingly to the axis of the lens for beam conversion. CONSTITUTION:The projection light from the semiconductor laser 1 whose optical axis 14 slants at an angle alpha to the axis of a condenser lens 12 is transmitted through the lens 2 and passed through magneto-optic crystal 5 to rotate the direction of polarization by 45 deg., and the light is passed through a polarizing and separating element 4 to propagate to the end surface 12 of an optical fiber 8 while converged. The axis of the element 4 is aligned so that there is no loss of the light in the polarizing and separating element 4. Reflected light from end surfaces 12 and 13, etc., of the optical fiber 8 is cut off by the magneto-optic crystal 5, and reflected light by end surfaces 9 and 10 of the lens 2 and the end surface 11 of the crystal 5 is never fed back to the semiconductor laser 1 because the optical axis 14 of the laser slants to the axis of the lens 2. |
