Eliminating Light Intensity Disturbance With Reference Compensation in Interferometers

In this letter, we introduce an improved phase-generated carrier (PGC) demodulation algorithm using reference compensation method to eliminate the influence of light intensity disturbance (LID) in interferometric fiber-optic sensors. In this method, the impacts of LID on acoustic signal and reference signal are the same. The impact of LID on reference signal can be measured via calculating the envelope variation of demodulated reference signal. Then, the impact of LID on acoustic signal is divided off through reference compensation. The improved PGC demodulation algorithm with merit of resisting LID was experimentally demonstrated. The signal-to-noise ratio of demodulation result based on the improved PGC algorithm achieves a gain of 11.78 dB over PGC algorithm using differential-cross-multiplying.

[1]  Gaosheng Fang,et al.  16-Channel Fiber Laser Sensing System Based on Phase Generated Carrier Algorithm , 2013, IEEE Photonics Technology Letters.

[2]  Alan D. Kersey,et al.  Polarisation-insensitive fibre optic Michelson interferometer , 1991 .

[3]  Qian Tian,et al.  Performance improvement of phase-generated carrier method by eliminating laser-intensity modulation for optical seismometer , 2010 .

[4]  Polarization properties of interferometrically interrogated fiber Bragg grating and tandem-interferometer strain sensors , 2006, Journal of Lightwave Technology.

[5]  Fang Li,et al.  PGC Demodulation Technique With High Stability and Low Harmonic Distortion , 2012, IEEE Photonics Technology Letters.

[6]  You-wan Tong,et al.  Improved phase generated carrier demodulation algorithm for eliminating light intensity disturbance and phase modulation amplitude variation. , 2012, Applied optics.

[7]  C. Lu,et al.  Frequency stabilization of DBR fiber grating laser using interferometric technique , 2001, IEEE Photonics Technology Letters.

[8]  Min Zhang,et al.  Analysis and Optimization of the PGC Method in All Digital Demodulation Systems , 2008, Journal of Lightwave Technology.

[9]  A. Kersey,et al.  Fiber Bragg grating array sensor system using a bandpass wavelength division multiplexer and interferometric detection , 1996, IEEE Photonics Technology Letters.

[10]  Benli Yu,et al.  Eliminating additional laser intensity modulation with an analog divider for fiber-optic interferometers , 2012 .

[11]  Min Zhang,et al.  Performance improvement of PGC method by using lookup table for optical seismometer , 2009, International Conference on Optical Fibre Sensors.

[12]  T. Giallorenzi,et al.  Homodyne Demodulation Scheme for Fiber Optic Sensors Using Phase Generated Carrier , 1982 .