variable delay line in optical fibre, method for making, switch to it and a frequency filter and filtration method with it made

摘要

PCT No. PCT/US82/01608 Sec. 371 Date Jun. 19, 1984 Sec. 102(e) Date Jun. 19, 1984 PCT Filed Nov. 12, 1982 PCT Pub. No. WO84/02005 PCT Pub. Date May 24, 1984.A single mode optical fiber switch having a base (70) and a laterally slidable top (91). The base is composed of a quartz block (70) with a slight radius of curvature along its length supporting a silicon substrate (66) having a plurality of parallel v-grooves (68). The grooves are fitted with single mode optical fiber segments (64) and lapped to create a flat coupling surface (82) extending laterally across the base. The top (91) is composed of a quartz block with a single v-groove (93) holding a segment of single-mode fiber (95). This fiber (95) is lapped to create a flat coupling surface matable with the coupling surface on the base. The base (70) and top (91) are placed together such that the top fiber (95) may be selectively slid into and out of coupling alignment with any of the fibers (64) in the base (70) to form a discretely variable delay line. A single length of fiber (121) is wrapped around the base ( 70) in helical fashion with each loop being secured in one of the v-grooves (68). By coupling the top fiber (95) with different loops of the base fibers (121), different amounts of delay can be obtained. The delay line can be used to provide variable frequency response for notch and transversal filters.