Design and nonlinearity compensation of Fabry-Perot type tunable optical filters for dynamic strain sensing systems

Abstract:

The collected spectrum of the fiber Bragg grating (FBG) and the loss of the detected optical power are discussed with respect to the 3-dB bandwidth of a Fabry-Perot (F-P) type tunable optical filter (TOF), respectively. And the optimized parameters of the TOF are obtained consequently. It is demonstrated that the relationship between the transmission wavelength of the TOF and its drive voltage is nonlinear. A new method to compensate the nonlinearity of the TOF is proposed.The linear sweeping of the transmission wavelength of the TOF is achieved through modifying the drive voltage using interpolation algorithm. It is observed that the average error and the maximum error of the transmission wavelength are reduced sharply under linear fit. The dynamic strain sensing is realized by use of a reference FBG and moving averaging algorithm in this system.