Improved Fiber Bragg Grating Bending-Sensor Using TE/TM Modes

After the advent of optical fibers and cheap respective parts, using fiber optic sensors flourished. Bending is one of the significant parameters by measuring which, using optical fiber sensors, mechanical system mode can be set. Advantages of the fiber optic sensors, especially fiber Bragg grating sensors, that are free from many of resistive sensor problems, attracted researchers to focus on bending sensors based on optical fibers. However, uncertainty is still a major challenge for developing such sensors. In this article, one fiber optic bending sensor is simulated attempting to increase accuracy. First, bending in fiber Bragg grating is simulated, observing characteristic changes of reflection and transmission in TE and TM modes according to bending. Then, the number of resonance peaks and related distance, in TE and TM modes, is employed to determine the radius of curvature. This method in comparison to previous methods based on the return wavelength measurement, is more accurate. Because the number of resonance peak and related distance changes versus bending changes is more than those of return wavelength changes.