Modeling of plasmon-polariton refractive-index hollow core fiber sensors assisted by a fiber Bragg grating

The theoretical model of a new hollow core fiber sensor based on the specific properties of the surface plasmon polariton (SPP) excited with a fiber Bragg grating is proposed and comprehensively investigated. The main principle of operation of this new device is based on the efficient energy transfer between the fiber waveguide mode (FWM) and the SPP provided by a properlv designed short-period fiber Bragg grating imprinted into a waveguide fiber layer of a specially designed hollow core optical fiber. The waveguide fiber layer is the dielectric layer of the fiber with the highest refractive index. The FWM is a fiber mode oscillating in this layer and exponentially decaying in all other fiber layers. Presented for the cylindrical (fiber) geometry, the scheme without loss of generality can be applied to the planar geometry. The simulations are based on the coupled mode theory and performed for well-developed telecom wavelength ranges.