A new simulation method for calculating of temperature and strain at the same time by fiber Bragg grating sensor

Excessive sensitivity of light waves emitted within optical fiber to environmental changes has led to the widespread use of optical fibers as sensors of environmental parameters such as temperature, strain, stress, humidity, density, and so on. Among the fiber optic sensors, the fiber Bragg grating (FBG) sensor has found many applications in various civil and industrial fields due to its high accuracy, reasonable sensing length and low price, but some limitations of this sensor has led to a significant reduction in performance. One of the most important of these limitations is the problems in measuring several environmental parameters at the same time, especially temperature and strain. This limitation has led to the suggestion of many methods for measuring temperature and strain at the same time, using the FBG sensor. Most of these methods have require more than one uniform FBG, and other methods use one special FBG to measure temperature and strain at the same time. Each of these methods have disadvantages such as requiring more than one uniform FBG, complexity in setup and overused of spectral sources. Our purpose in this paper is to numerical simulation as well as design a suitable setup for calculating temperature and strain changes at the same time, by a single uniform FBG. Based on the simulation results obtained from MATLAB software, the sensitivity of this sensor is 14 pm/℃ for temperature and 0.678 pm/με for strain.