| 摘要 |
PURPOSE:To improve the yield of the coupler and to reduce the cost thereof by providing a substrate which is formed with a two-dimensional light guide and cylindrical Fresnel lenses which are disposed to at least either of the incident and exit end faces of the light guide and condense collimated beams of light only in the one-dimensional direction to the coupler. CONSTITUTION:The cylindrical Fresnel lenses 1, 11 are disposed to both end faces of the two-dimensional light guide 6 formed on the substrate 5 in such a manner that the condensing direction of the lenses and the thickness direction of the light guide 6 coincide. The exist end face of the optical fiber 2 for incidence and the incident end face of the optical fiber 12 for emission are optically coupled to the cylindrical Fresnel lenses 1, 11 respectively via rod lenses 3, 13. Since the cylindrical Fresnel lenses 1, 11 are disposed in proximity to or in contact to the end face of the light guide 6 in such a manner, the need for forming the waveguide lens as a collimator lens in the light guide is eliminated. The high yield is maintained in this way and the cost is reduced. |
