| 摘要 |
PURPOSE:To obtain good coupling of a single mode optical fiber and a semiconductor laser, by providing a medium part consisting of the same substance between a semi-spherical lens of the tip and the end face of an optical fiber. CONSTITUTION:A semi-spherical lens 2 whose radius is R is fitted through a medium part 6 to a tip part 5 of a fiber consisting of a core 3 and a clad 4. The medium part 6 consists of a material having an equal quality to the semi-spherical lens 2, its length is denoted as zeta and a distance between a laser chip 1 and the fiber tip is denoted as (z). A distance between the fiber tip and a (z) axis, and inclination from the (z) axis are denoted as dy and phiy, as a symbol for showing a position shift of the laser chip 1 on a (yz) plane and a fiber 7, and as a result of an experiment by varying a numerical value of said symbol in various ways, it becomes clear that the maximum coupling efficiency is obtained when the radius R is within a range of 10<=R<=100(mum) and the length zeta of the medium part is 5.6R -22<=zeta<=154R-5(mum). Accordingly, the coupling efficiency is increased without reducing the radius of the lens, and a loss of the coupling efficiency due to a horizontal shift can be reduced. |
