METHOD OF FORMING AN OPTICAL FIBRE COUPLER AND A COUPLER SO FORMED

摘要

Six secondary optical fibres (20) are located about and parallel to a central op tical fibre (21) by a capillary tube (22) to form a fibre bundle which is then formed into a fused, tapered coupler in which the tapering is stopped when the proportions of light coupled out of the central fibre (21) at 1.3 and 1.53 .mu.m are first equa l. The fusion process can provide sufficient fusion between the central fibre and each secondary fibre to provide a 1 to (n + 1) cou pler where n is the number of secondary fibres. This method provides a coupler which is wavelength-flattened between 1.3 and 1.53 .mu .m using similar fibres.