| 摘要 |
PURPOSE:To provide a method for adjusting the projecting length of window material of an optical transmission tube capable of preventing thermal deterioration of a mouth piece part by the temp. rise thereof and deterioration of the peripheral member of the mouthpiece part at the time when the light from a light source is absorbed by the window material of optical transmission tube and to provide an optical transmis sion tube having the window material or a rod adjusted by this method. CONSTITUTION:The optical transimssion tube B is provided with a transparent core 1, a clad 2 having a refractive index lower than the refractive index of the core, a transparent window material 3 for light incidence inserted at least at one end of the clad 2 and a mouthpiece part 4 for fastening and fixing the window material 3 and the clad 2. The projecting length of the window material 3 of the optical transmission tube B from its mouthpiece part 4 is adjusted so as to satisfy the equation. In the equation, L denotes the projecting length of the window material 3, D denotes the diameter of the window material 3, n1 and n2 respectively denote the refractive indices of the window material 3 in the outside part (clad 2) of the projecting part of the window material 3. |
