الفهرس 
GENERAL INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
In recent years, many research and development projects have been focused on studying the Tilted Fiber Bragg Grating (TFBG). TFBGs have been used in sensors and communication systems. The researchers are working towards better understanding physical processes underlying operation of TFBGs. This should facilitate new applications such as biosensing,chemical sensing and combination with other physical phenomena such Second Harmonic Generation (SHG).The goal of this thesis is to construct a model for a TFBG using MatLab and explore new applications using TFBGs. Using a framework of optical waveguide theory, a firm understanding of the research on TFBGs is gained. The process of mode ling TFBGs involve studying the process of mode coupling within a fiber distinguishes the main two types of TFBGs and finally illustrates the transmission and reflection spectra Based on the theoretical studies, this thesis introduces a novel technique to generate a second order nonlinearity using TFBGs coated by a nonlinear material, which causes an enhancement of the overall SHG efficiency that can be produced in optical fibers. Also, studying the effect of different apodizd grating profiles promotes to increase the sensors sensitivity that use TFBGs.It can be concluded that the TFBGs are separated into Reflective- TFBG and Transmissive-TFBG. In Reflective- TFBG, grating period is determined to be < 1 um. While, in Transmissive- TFBG, grating period range is typically from less than 10 um to 600 um, The coupling through TFBGs depends on fiber parameters (core radius, cladding radius, grating period, the tilt angle), and the surrounding medium. In Reflection- TFBG, It can be observed that as tilt angle increase the Full Wave at Half Maximum (FWHM) of Bragg mode decrease and the sidelobes are minimized in the expense of decreasing the maximum peak of reflection mode. For improving the result, the gratings are going to be apodized with different profiles. When the gratings are apodized, sidelobes are suppressed, especially when using Nuttall profile, while Tanh profile offers the minimum FWHM In Transmissive- TFBG, The cladding modes are exploited to generate Second Harmonic Signa(SHS) in the cladding of optical fibers with overall power efficiency approach to 2 x 10-3.