NARROW-BAND FILTER

摘要

PURPOSE:To provide the narrow-band filter which has mass productivity, is small and inexpensive and has the excellent characteristics of fiber pigtails. CONSTITUTION:An optical filter 9 of the filter input/output type filter consisting of at least one piece of optical fibers 7 fixed onto a substrate 11, at least one piece of grooves 10 formed to cross the core parts of the optical fibers 7 and the leaf-like optical filter 9 disposed in the grooves 10 is a band-pass filter of a single cavity type and is the narrow-band filter expanded in the mode field near the groove forming parts of the optical fibers.