Realization of a polarization-insensitive optical frequency-domain reflectometer using an I/Q homodyne detection

AbstractWe report on the development and implementation of an optical frequency-domain reflectometer (OFDR) sensing platform. OFDR allows to measure changes in strain and temperature using optical fibers with a length of several tens of meters with very high spatial resolution. We discuss the operation principles and challenges to implement an OFDR system using optical homodyne detection based on a dual-polarization 90° optical hybrid. Our setup exhibits polarization and phase diversity, fully automated data acquisition and data processing using a LabVIEW-based implemented software environment. Using an optical hybrid enables to discriminate phase, amplitude and polarization by interfering the Rayleigh scatter signal and a local oscillator with four 90° phase stepped interferences between the two signals. Without averaging and a fast acquisition time of 230 ms, our preliminary results show a spatial resolution of 5 cm and a temperature resolution of about 0.1 Kelvin on a 3 m-long fiber.

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Realization of a polarization-insensitive optical frequency-domain reflectometer using an I/Q homodyne detection

10.21203/rs.3.rs-150679/v1 ◽

2021 ◽

Author(s):

Alin Jd ◽

Marcelo A. Soto ◽

Marius Enachescu ◽

Dominik Ziegler

Keyword(s):

Frequency Domain ◽

Spatial Resolution ◽

Optical Fibers ◽

Local Oscillator ◽

Acquisition Time ◽

Optical Frequency ◽

Homodyne Detection ◽

Software Environment ◽

Very High Spatial Resolution ◽

Phase Amplitude

Abstract We report on the development and implementation of an optical frequency-domain reflectometer (OFDR) sensing platform. OFDR allows to measure changes in strain and temperature using optical fibers with a length of several tens of meters with very high spatial resolution. We discuss the operation principles and challenges to implement an OFDR system using optical homodyne detection based on a dual-polarization 90º optical hybrid. Our setup exhibits polarization and phase diversity, fully automated data acquisition and data processing using a LabVIEW-based implemented software environment. Using an optical hybrid enables to discriminate phase, amplitude and polarization by interfering the Rayleigh scatter signal and a local oscillator with four 90° phase stepped interferences between the two signals. Without averaging and a fast acquisition time of 230 ms, our preliminary results show a spatial resolution of 5 cm and a temperature resolution of about 0.1 Kelvin on a 3 m-long fiber.

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Enhancement of the Performance and Data Processing Rate of an Optical Frequency Domain Reflectometer Distributed Sensing System Using A Limited Swept Wavelength Range

Sensors ◽

10.3390/s18103480 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3480 ◽

Cited By ~ 4

Author(s):

Kunpeng Feng ◽

Jiwen Cui ◽

Yihua Jin ◽

Xun Sun ◽

Dong Jiang ◽

...

Keyword(s):

Data Processing ◽

Frequency Domain ◽

Spatial Resolution ◽

Wavelength Range ◽

Distributed Sensing ◽

Optical Frequency ◽

Local Similarity ◽

Processing Rate ◽

Spectrum Range ◽

Measurable Range

A novel optical frequency domain reflectometer (OFDR) processing algorithm is proposed to enhance the measurable range and data processing rate using a narrow swept spectrum range and reducing the time consuming of the process distributed sensing results. To reduce the swept wavelength range and simultaneously enhance strain measurable range, the local similarity characteristics of Rayleigh scattering fingerprint spectrum is discovered and a new similarity evaluation function based on least-square method is built to improve the data processing rate and sensing performance. By this method, the strain measurable range is raised to 3000 µε under a highest spatial resolution of 3 mm when the swept spectrum range is only 10 nm and the data processing rate is improved by at least 10 times. Experimental results indicate that a nonlinearity of less than 0.5%, a strain resolution of better than 10 µε, a repeatability at zero strain of below ±0.4 GHz and a full-scale accuracy is lower than 0.85 GHz under a highest spatial resolution of 3 mm can be achieved. Advantages of this method are fast processing rate, large strain measurable range, high SNR, and applicability with current OFDR systems.

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