22 November 2011 An improved PGC demodulation method to suppress the impact of laser intensity modulation
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Proceedings Volume 8199, 2011 International Conference on Optical Instruments and Technology: Optical Sensors and Applications; 81990Q (2011) https://doi.org/10.1117/12.903706
Event: International Conference on Optical Instruments and Technology (OIT2011), 2011, Beijing, Beijing, China
Abstract
An improved demodulation method by solving a quadratic equation was proposed for the phase generated carrier (PGC) scheme with frequency modulation to suppress the impact of laser intensity modulation (LIM). The influence of LIM on total harmonic distortion (THD) was analyzed for PGC algorithm considering laser intensity modulation coefficient (LIMC), signal amplitude, initial phase and modulation depth. According to our analysis, the maximum THD of PGC algorithm is more than -24dB when LIMC is 0.1. While the maximum THD is less than -65dB by using the improved method when LIMC is less than 0.5, which is limited by the low-pass filter. For an experiment system with 0.285 LIMC, the THD was -9dB for PGC algorithm. By using the improved method, the THD approached -50dB.
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Huayong Zhang, Min Zhang, Liwei Wang, Yanbiao Liao, D. N. Wang, "An improved PGC demodulation method to suppress the impact of laser intensity modulation", Proc. SPIE 8199, 2011 International Conference on Optical Instruments and Technology: Optical Sensors and Applications, 81990Q (22 November 2011); doi: 10.1117/12.903706; https://doi.org/10.1117/12.903706
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