A fiber loop mirror, or fiber loop reflector, is a simple reflecting device for fiber optics, made by connecting two ports of a fiber coupler with a fiber loop; it can be considered as a Sagnac interferometer. In the linear regime with a 50:50 coupler, it acts as a perfect reflector. In this case, the two waves travel with identical optical paths in. In this paper, a different Fiber Loop Mirror (FLM) configuration with two circulators is presented. This configuration is demonstrated and characterized for sensing applications. This paper presents a novel fiber loop mirror. With exceptional durability, the Fiber Optic Sensor Focusing Lens is built to perform reliably in harsh industrial environments over extended periods. It optimizes detection precision and sensitivity, minimizes environmental interference, and meets the demanding requirements of high-accuracy. A Faraday mirror (or Faraday rotator mirror) is made by combining a Faraday rotator (for 45° rotation) with a mirror.
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