Theoretical Analysis of Fiber-Optic Evanescent Wave Sensors

A large penetration depth of an evanescent wave is the key to success for developing a fiber-optic evanescent-wave sensors. In general, the penetration depth of an optical fiber, stripped off its cladding, is relation to the wavelength of incident light, the refractive index of the surrounding medium and the incident angle on the basis of ray-tracing model. When the tapered optical fiber is analyzed, a mathematical solution of the wave equation is more suitable.