OPTICAL SWITCH

PURPOSE:To eliminate the need for a magnet, etc., and to form a smaller-sized optical switch by disposing optical fibers wound with superconducting materials like coils to face each other. CONSTITUTION:A wire rod of 20mum outside diameter consisting of Y2BaCuO7 ceramics is coiled on the step index type quartz optical fiber of 125mum outside diameter and 50mum core diameter. A piece of such optical fiber is disposed on one side and 3 pieces of the optical fibers on the other in a manner that the fibers can face said fiber. The Y2BaCuO7 ceramics is brittle and is, therefore, coated with a quartz glass capillary. Both faces of the optical fibers face each other at a spacing 5mum when the central axes thereof align. Electric current is passed at 10 /cm to the superconductive fine wire in such a manner that the front end of the left optical fiber is an S pole. The entire part is cooled to 77 deg.K at this time. On the other hand, the current is impressed to the right side optical fibers in such a manner that only the front end of the upper fiber is an N pole. As a result, he left side optical fiber is coupled to the upper optical fiber in the right side optical fibers and the connection loss thereof is decreased as low as 0.1dB.