Theoretical Investigation of a Long Period Grating Sensor Employing Multilayer Fiber Geometry

A theoretical formulation of the long-period grating sensor is implemented with respect to efficient refractive indices of core and cladding. The obtained result is utilized further for determination of ERIs of core and cladding using graphical analytical method and multilayer fiber geometry. ERI values of primary guided core, bi and tri layer fiber geometry using MATLAB software. In the present paper effective refractive index of core and cladding for the two and three layers have been investigated. The cladding modes have also been calculated using Erdogan’s proposed three-layer geometry as well as two-layer graphical solution method. We have compared both the techniques, discussed the limitations of graphical solution method and the benefits of three-layer geometry.