Development of Fiber Optic Refractive Index Sensor Using Speckle Pattern Imaging

In this study, a fiber optic sensor was designed by using the speckle pattern images occured at the output of multimode fibers to perform the refractive index measurement. The sensing process was performed by establishing a correlation relationship between the images obtained from the fiber output. A part of the optical fiber was tapered to sense refractive index. By using the beam propagation method, the tapered fiber sensor was simulated and it was shown that the sensor could make sensitive measurements in the range of 1.3300-1.3307 of refractive index. Proposed sensor design, which is a basic design of the refractive index fiber sensor, can be developed for different measuring ranges and different several physical variables such as temperature, pressure, bending, stress, force etc.