JPS5768818A - Optical switch - Google Patents

Abstract

PURPOSE:To elevate the reliability of a switch, and also to execute the operation at a high speed, by additionally providing an electromagnet whose magnetic core is a semihard magnetic material, in the proximity of a Faraday element for changing a polarized direction, in case of switching an optical path which is used for optical communication, etc. CONSTITUTION:An incident light beam which has passed through a polarizer 1 is linearly polarized and goes into a Faraday rotary element 10. To the element 10, an electromagnet 11 whose core is a semihard magnetic material 12 of a self-holding type, for instance, consisting of nibcoroy, and to which an energizing coil 13 has been wound is placed in its proximity. When a pulse current I is made to flow to a coil 13, the magnetic material 12 is energized, for instance,i by N and S shown in the fiigure, generates a magnetic field H, and holds the magnetic field H even if it is stopped to apply the pulse. Subsequently, when a pulse current -I is made to flow in the reverse directon, the direction of the magnetic field is reversed to -H, and the magnetic field -H is held even if it is stopped to apply the pulse. Accordingly, as for an incident light beam to the element 10, the polarized direction is changed by a direction of the pulse current I, it is separated and fetched by a polarizing and separating element 4, and the optical path is switched electronically.