Spectral contour length demodulation method for tilted fiber Bragg grating refractive index sensing

Sławomir Cięszczyk, Waldemar Wójcik, Andrzej Smolarz, Ryszard S. Romaniuk
2019 Optical Fibers and Their Applications 2018  
The spectral response of the uniform FBG with different grating parameters such as grating length and index change are provided and discussed. The coupled mode theory is a suitable tool for analysis and obtaining quantitative information about the spectrum of a fiber Bragg grating. The coupled mode equations can be obtained and simplified by using the weak waveguide approximation. The spectrum characteristics can be obtained by solving these coupled mode equations. In this paper simulation of
more » ... per simulation of FBG has been carried out to analyze the spectral characteristics of the FBG. An optical FBG is being simulated with the help of advanced software module such as the R soft and the modeled sensor is evaluated for the grating and different efficiency of various grating shape parameters, modulation depth,etc. The relationship between the maximum reflectance, 3dB bandwidth and centre wavelength with grating parameters are also given and discussed. Optimization and improvement of the system can be realized by using the simulation results. Since the present work not only deals with theoretical aspects of FBGs but also leads to the development of simulation tools which can be used in the area of communications and sensors. 457 of an optical fiber[6], [7] . FBG sensors are based on the fact that the Bragg wavelength changes with change in the pitch of the grating and the change in the refractive index. Thus any physical parameter (like temperature, stress, strain) which causes change in the above mentioned parameters can be sensed using a FBG by measuring the shift in the Bragg wavelength or the change in reflection coefficient of a particular wavelength[8], [9] . Refractive index of an optical fiber can vary with changes in temperature and therefore the spectral response of FBGs is also temperature dependent [10] . They are used as flexible and low cost inline components to manipulate any part of the optical transmission and reflection spectrum. The spatial quality of FBGs determines the performance of the FBG based optical communication devices. FBG is the key component for dispersion compensation and WDM [11] .
doi:10.1117/12.2520216 fatcat:ofy77ri2qva6nlhkrj7uekr25a