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Published on: March 10, 2011
Experimental study on phase noise induced interference in COTDR systems
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Phase noise induced interference (PNII) is an important noise source for COTDR systems. In our previous work, we presented the theoretical framework for understanding PNII. In this paper, building upon this theoretical foundation, we conduct a comprehensive experimental investigation into PNII. A laser source with an adjustable linewidth within a wide range from kHz to MHz is employed. The control of the laser linewidth is achieved by applying a Wiener process phase noise signal to an optical IQ modulator. The experimental measurements have a good agreement with the theoretical prediction. Additionally, a vibration detection experiment based on a COTDR system equipped with the linewidth-adjustable laser is carried out to further validate the derived theoretical analysis. Our in-depth study of PNII not only deepens the understanding of the impact of phase noise on COTDR systems but also provides a solid foundation for appropriate selection of laser sources in COTDR systems.
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