JPS5784423A - Optical device - Google Patents

Abstract

PURPOSE:To obtain an optical device for limiting the wavelength of a transmission light beam, by forming a metallic or dielectric thin film on the end of an optical fiber which has been cut in the 45 deg. direction. CONSTITUTION:The first optical fiber 31 is cut and polished in the 45 deg. direction against the optical axis, a metallic or dielectric thin film 33 is formed on its end, and also the second optical fiber 32 which has been cut in the 45 deg. direction against the optical axis, as well, is brought into contact with said first optical fiber 31. On an optical axis l having an end of 45 deg. against the optical axis of this optical fiber, an optical semiconductor element 41 constituting an optical signal source or a photodetecting part is placed. When plural optical fibers 31, 31'... having such constitution are connected through filters 33, 33'..., the wavelength of a transmission light beam is selected, and an optical transmission line which is capable of a large quantity of transmission is constituted.