Dynamic temperature-strain discrimination using a hybrid distributed fiber sensor based on Brillouin and Rayleigh...

Area of Science:

• Optoelectronics
• Fiber optic sensing
• Materials science

Background:

• Distributed fiber sensors are crucial for monitoring physical parameters.
• Existing methods struggle with simultaneous, low-noise dynamic temperature and strain discrimination.
• Advances in Brillouin and Rayleigh scattering offer new possibilities for sensor design.

Purpose of the Study:

• To develop a hybrid distributed fiber sensor for simultaneous temperature and strain measurement.
• To achieve low-noise, high-speed dynamic sensing capabilities.
• To improve upon the resolution and cross-sensitivity of existing fiber optic sensors.

Main Methods:

• Integration of a slope-assisted Brillouin optical time domain analysis (BOTDA) system.
• Incorporation of a Rayleigh-scattering-based frequency scanning optical time domain reflectometry (FSOTDR) system.
• Development of a hybrid sensor combining BOTDA and FSOTDR for enhanced performance.

Main Results:

• Achieved quasi-static temperature resolution of 16 m°C and strain resolution of 140 nɛ over 500 m with 5 m spatial resolution.
• Enabled dynamic measurements with a 1.7 kHz bandwidth and low noise spectral density (0.54 m°C/√Hz for temperature, 4.5 nɛ/√Hz for strain).
• Suppressed temperature/strain cross-sensitivity by at least 25 dB.

Conclusions:

• The hybrid sensor demonstrates a significant advancement in dynamic temperature/strain discrimination using standard single mode fiber.
• This technology offers unprecedented measurement speed and sensitivity for distributed fiber sensing.
• The system provides a robust solution for applications requiring precise, simultaneous monitoring of temperature and strain.