| 摘要 |
PURPOSE:To realize coupling of a fiber and a waveguide with extremely high efficiency without generating a connection loss, by forming a refractive index distribution shape of the waveguide so as to coincide almost in the same diameter, with an optical transmission part of the optical fiber which is connected to the waveguide end. CONSTITUTION:A refractive index distribution of a waveguide 2 for connecting the refractive index distribution type optical fibers 5A-5C is formed so as to coincide almost in the same diameter, with an optical transmission part of the fiber. When a section having such a refractive index distribution embeds and forms a practically circular waveguide 2, for instance, the surface of a transparent multi-component compound glass substitute 1 is brought to masking by leaving an opening of a prescribed circuit pattern. Subsequently, an ion which is contributed to an increase of the refractive index of the substitute 1 glass, such as a Tl ion, etc., is diffused by exchanging it with an ion in the glass, through the opening. Thereafter, the titled circuit is formed by eliminating the masking and diffusing an ion which is contributed to a decrease of the refractive index of the glass, such as an Na ion, a K ion, etc. In this way, the connection loss becomes extremely small, and a transmission light of the fiber is efficiently led into the waveguide. |
