| 摘要 |
PROBLEM TO BE SOLVED: To reduce eclipse loss in a lens and to couple an LD element and an optical fiber with high efficiency by arranging a 1st and a 2nd lens between the LD which is large in the projection angle of a beam parallel or perpendicular to the active layer of the ID element and the optical fiber. SOLUTION: The LD element 5 which is in the horizontal direction (a) and vertical direction (b) to the active layer of the LD element 5 is made large in the projection angle to the beam perpendicular to the active layer. A 1st lens 6 is machined in a wedgelike shape by providing slopes on both sides from the center line only in case of the vertical direction and the center part is given curvature. A 2nd lens 7 converges the light passed through the 1st lens 6 and is cut obliquely to the vertical direction. The optical fiber 3 is polished obliquely to the vertical direction according to the oblique cutting angle of the 2nd lens 7. In this constitution, part of large-projection-angle light components of the beam which are not normally converged by the lens is coupled with the optical fiber 3 by using light refraction effect.
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