PGC demodulating scheme based on CORDIC algorithm for interferometric optical fiber sensor

Abstract

One important advantage of interferometric optical fiber sensor is high sensitivity. The development of the interferometric optical fiber sensor is partly restricted with the demodulating technique. Because of advantages such as high sensitivity, high dynamic range, and good linearity, PGC (Phase Generated Carrier) demodulating scheme is widely applied for interferometric optical fiber sensor now. In this paper, an arctangent approach of the PGC demodulating scheme is introduced. CORDIC (Coordinate Rotation Digital Computer) algorithm is used to realize the arctangent function. CORDIC algorithm is a method for computing elementary functions using minimal hardware such as shifts, adds/subs and compares. CORDIC algorithm works by rotating the coordinate system through constant angles until the angle is reduces to zero. The angle offsets are selected such that the operations on X and Y are only shifts and adds. This method will lead in less complexity and higher accuracy. Since digital signal processing technology has achieved great development, especially the appearances of high speed processors such as FPGA and DSP, PGC demodulating scheme based on CORDIC algorithm is implemented conveniently. The experiments are carried out to verify the PGC demodulating scheme based on CORDIC algorithm.