| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical coupling module (polarized wave synthesis/ demultiplexing module) of a new structure which is smaller than conventional one and expected to be improved in the performance. SOLUTION: This optical coupling is provided with a lens 41 of a focus distance f, a first and a second waveguide means 43, 45, and 2×1 optical elements 51. The first and second waveguide means 43, 45 are positioned so that at least one-end pair of them become parallel with each other and also face a first surface 41a of the lens 41 at a position where the end faces of the one-end pair satisfy a relationship 1/a+1/b=1/f. 2×1 optical elements 51 are constituted of double refractive crystal 47 and an optical focusing system 49. The optical focusing system 49 focuses one of the light beams emitted from the parts corresponding to two input/output ports 47a, 47b in the double refractive crystal 47 on a position b satisfying the relation ship 1/a+1/b=1/f about the waveguide means 43, and focuses the other light beam on a position satisfying the relationship 1/a+1/b=1/f about the waveguid 45. |
