| 摘要 |
PURPOSE:To produce a T type light branching/coupling circuit which can change its branching ratio (coupling ratio) by using a semitransmitting mirror, a polaroid beam splitter, 1/4 wave-length plates and a reflector. CONSTITUTION:Light projected from an optical fiber 2 is separated into polarized light P and S; the polarized light P is transmitted and coupled with an optical fiber 3 and the polarized light S is passed through a 1/4 wave-length plate 15 twice through a reflector 17 and transmitted and coupled with an optical fiber 1 through a 1/4 wave-length plate 16 and a semitransmitting mirror 18 with reflection factor alpha. When the reflection factor of the semitransmitting mirror 18 is alpha, the coupling efficiency between the optical fibers 2 and 3 is 0.5(1+alpha) and the efficiencies between the optical fibers 1 and 2 and between 1 and 3 are 0.5(1-alpha) respectively, so that the branching ratio can be optionally set up by changing the reflection factor alpha. |
