PRODUCTION OF OPTICAL DEMULTIPLEXER

PURPOSE:To work the end faces of optical fibers easily with high accuracy and to mate the surfaces of filter films with high accuracy by sticking optical fibers and a base plate to one body, then working the same and mating the end faces of the base plates. CONSTITUTION:An optical fiber 10 is stuck by means of an adhesive agent to the V-groove 9 formed on the top surface 8'' of a base plate 8 having a rectangular section. With the bottom surface of the plate 8 as a reference plane, the end face 8' of the base plate of the angle that said surface assumes to the top surface 8'' is acute and the end face 10' of the optical fiber are worked, for example, polished, at the desired angle alpha to the axial center of the fiber 10. Thereafter, a filter film 11 is formed, for example, vapor deposited, on the end surface 10' of the fiber 10. The end face 15' of a base plate 15 is stuck to the end face 8' of the plate 8 in such a way that the axial center of an optical fiber 16 aligns to the axial center of the fiber 10 and that a filter film 17 contacts tightly with the film 11. Thus, the end faces of the optical fibers are worked easily with high accuracy, and the surfaces of the filter films are mated with high accuracy.