A Simple and Cost-Effective Metal Coating Method for Reflective Long Period Grating Sensors

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Conference Proceeding

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A novel and cost-effective technique to coat a fiber optic long period grating (LPG) sensor with silver paste to realize a reflection mode operation is presented here. LPGs have higher sensitivity compared to fiber Bragg grating (FBG) and are typically used as a transmission sensor. Recently, reflective LPG structures have been realized by coating the end of the LPG fiber with metal, but they have limitations as the fabrication process to coat the fiber with metal is either expensive or complex. In our work, we show a novel inexpensive technique to coat long lengths (60 cm or longer) of LPG with silver. The fabricated reflective LPG mimics the transmitted spectrum with improved selectivity. This simple coating method can be applied for other optical fiber sensors; such as metal embedded sensors for monitoring parameters at such critical locations not accessible to ordinary sensors.