Microfiber-Wrapped Bi-Conical-Tapered SMF for Curvature Sensing

We propose a microfiber-wrapped-based structure for curvature measurement. The sensor is fabricated by wrapping a microfiber of 8.6 μm around a bi-conically tapered single mode fiber (SMF). The light is launched through the SMF, and in the tapered region, the light radiated out of the SMF gets coupled to the microfiber. As the curvature of the sensor is increased, more light gets radiated out of the tapered SMF, and hence, the intensity of the light collected from the microfiber also increases. We have achieved a maximum curvature sensitivity of 20.98 dB/m^-1 for the curvature range 0-0.5 m^-1. The sensor is almost insensitive to temperature change. Since only standard SMF is used for sensor fabrication and sensing is based on intensity, the proposed sensor may open a new window for economical curvature sensing.