In order to study the properties of phase-shifted fiber Bragg grating, The reflection spectrum characteristic of phase-shifted fiber grating with different fiber grating length, different refractive index modulation depth and different shift angle are analyzed using transmission matrix method. A new scheme of optical add-drop multiplexer based on phase-shifted fiber Bragg grating and Mach-Zehnder interferometer is proposed and simulated. The reflection spectrum of phase-shifted fiber grating is optimized using Gauss apodization function. Two channel signals can be dropped simultaneously. This study may provide theory instruction for the application of the OADM.
A fiber Bragg grating (FBG) sensor for simultaneous measurement of temperature and force is proposed and demonstrated. Where a part of uniform FBG (about one half length of an FBG) is attached on the polymer open loop, the FBG is divided into two parts which has an equal length. So the two parts can be regarded as two FBGs. Because of the difference of the Young’s modulus and the thermal expansion coefficients for two parts of the FBG, the two Bragg reflection wavelengths are shift when the temperature and force are applied on the sensor. Simultaneous measurement of temperature and force is demonstrated experimentally. The experimental results show that the linear response to temperature and force are achieved. The value of applied temperature and force can be obtained from the two Bragg wavelength shift via the coefficient matrix. This study provides a simple and economical method to measure temperature and force simultaneously.