Optical fiber coupler with attenuator

摘要

An attenuating centrosymmetric reflective (CSR) device is provided for controllably coupling optical energy between pairs of optical fibers. The CSR-based attenuating device comprises a CSR coupler having a neutral density attenuating plate inserted between a fiber holder portion of the device and the reflecting mirror. The attenuating plate is preferably of variable density so that translation of the attenuating plate across the path of the beams results in varying attenuation. In a specific embodiment, back reflections to the source are eliminated by positioning the variable density attenuator plate at an angle large enough so that reflections of all reflected rays exceed the acceptance angle of the fiber ends. The variable density attenuating plate may be manually or automatically moved to obtain the desired attenuation.