Optical fiber filter and its production

PURPOSE: To obtain an optical filter having an extremely acute and narrow band. CONSTITUTION: The optical fiber filter has two ferrule assemblies 22, 22 and each assembly 22 consists of an wafer 30 and a ferrule 24. The wafer 30 and the ferrule 24 have a passage 26 into which an optical fiber 29 is inserted and the wafer 30 is joined with the ferrule 24 through a mirror 40 so as to align passages 26, 32. The two ferrule assemblies 22, 22 are aligned so as to have a prescribed interval between them and fitted to a supporting board 36. Namely a resonance state can be obtained by suitably adjusting the length of hollows between the wafer and the mirror 40 and between the mirror 40 and the ferrule 24 and only specific wavelength can be passed. COPYRIGHT: (C)1992,JPO