| 摘要 |
PURPOSE:To obtain the titled optical isolator which abounds in productivity, is high in performance and low in cost, by placing a parallel plate of a magneto-optical crystal which has been accumulated on a substrate and both faces of the substrate, by inclining it against an optical axis. CONSTITUTION:A magneto-optical crystal 1 is grown on both faces of a substrate 11. Subsequently, the crystal 1 which has been growth on the substrate 11 and both its faces is polished to an oblique columnar shape. Subsequently, a parallel plate which has been formed in thus way is stuck into a cylindrical tube 17 of a fluorine resin. Thereafter, this cylindrical tube 17 is placed in a columnar hole of an SmCo magnet 22. Next, the crystal 1 of both faces of the substrate 11, the magnet 22 and a polarizer 3 are placed concentrically against the optical axis of a light beam emitted from a semiconductor laser 23, by which an optical isolator is formed. A linearly polarized light which has been emitted from a laser 23 passes through a lens 21, and thereafter, rotated by 45 deg. as to its polarizing direction at the time of passing through the crystal 1, passes through the polarizer 3 and coupled to an optical fiber 19. On the centrary, when a reflected light returns to the laser 23, it is orthogonal to the polarizing direction of an oscillated light of the laser 23, therefore, it does not become the cause of a noise of the laser 23. |
