Slightly tapered optical fiber with inner air-cavity as a miniature and versatile sensing device

摘要

A long-standing goal of optical fiber sensors is the development of a miniature and versatile optical fiber device, which is capable of performing multiple sensing functions, and supporting a simple and efficient system. Here, we demonstrate an elegant way of achieving such a device by use of an inner air-cavity in a slightly tapered optical fiber. Owing to the small size of only a few tens microns and inner cavity structure, a spatially precise 'point sensing' with high sensitivity and good robustness can be readily achieved. The refractive index, strain, and temperature sensitivities obtained are ?1060 nm/RIU (refractive index unit), 22.5 pm/£g£`, and 80 pm/¢XC, respectively. The inner air-cavity-based device is flexible, ultracompact, versatile, and highly efficient, which provides a promising new way for a wide range of optical fiber sensing applications.