| 摘要 |
PURPOSE:To eliminate the reflected light from fiber end faces by so arranging the device that the fiber incident end is filled with a medium having a refractive index nearly equal to that of the fiber and that th boundary face of the medium has an angle not being zero with respect to the optical axis of incident light. CONSTITUTION:An optical fiber 5 is contained in a cell which is filled with refracting liquid 6 having a refractive index nearly equal to that of fiber blank and the incident light boundary face 1 of said case has an inclination of theta(thetanot equal to 0) with respect to incident light axis 4. In general, it is desirable to take the angle theta within a range at which the funnel reflection loss of the incident light does not sharply increase. On the other hand, the fiber 5 is fixed by a sleeve or the like which is in the refrecting liquid 6 and has an inside diameter nearly equal to the outside diameter of the fiber and the angle theta'' that the fiber assumes with respect to the incident light axis is by formula-(1). Here, in order to maximize the excitation efficiency of the fiber, it is desirable that theta'' be by formula (2). |
