| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical coupler which connects a planar integrated circuit having large specific refractive index difference to an optical fiber with low loss. <P>SOLUTION: In an optical coupler which consists of a core part 1 and a clad part 2 and which is equipped with a tapered waveguide 4a which is formed so that a core width is contracted to the propagation direction of an optical signal, a spot size is expanded by contracting the cross-sectional area of the core at the tip of the tapered waveguide 4a substantially while reducing density of at least one of the elements composing the core part. As a result, the optical coupler can reduce coupling loss with the optical fiber. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
