Method of forming a refractive index grating in an optical waveguide

摘要

PCT No. PCT/GB91/00452 Sec. 371 Date Nov. 3, 1992 Sec. 102(e) Date Nov. 3, 1992 PCT Filed Mar. 26, 1991 PCT Pub. No. WO91/15787 PCT Pub. Date Oct. 17, 1991.An optical fibre is fixed against a first face of a prism. A coherent beam of optical radiation is directed at the prism such that a portion B propagates directly to the first face while a second portion propagates via total internal reflection at a second face. The interference of the two portions creates a refractive index grating in the fibre at a wavelength longer than that of the radiation. The method provides a stable and simple method of sidewriting of waveguide gratings.