Optimization of a DPP-BOTDA sensor with 25 cm spatial resolution over 60 km standard single-mode fiber using Simplex...

Area of Science:

• Optoelectronics
• Fiber Optic Sensing
• Photonics

Background:

• Distributed optical fiber sensing offers long-range monitoring capabilities.
• Brillouin optical time-domain analysis (BOTDA) is a key technique for strain and temperature sensing.
• Existing BOTDA methods face limitations in spatial resolution and signal-to-noise ratio (SNR).

Purpose of the Study:

• To enhance the spatial resolution and measurement performance of BOTDA systems.
• To investigate the combined effects of optical pre-amplification and optimized pulse coding in DPP-BOTDA.
• To demonstrate sub-meter spatial resolution over extended fiber lengths.

Main Methods:

• Implementation of differential pulse-width pairs (DPP) in BOTDA.
• Optimization of Simplex coding with return-to-zero pulses through simulations for improved SNR and reduced spectral distortion.
• Integration of linear optical pre-amplification to boost receiver sensitivity and dynamic range.

Main Results:

• Achieved a record spatial resolution of approximately 25 cm.
• Demonstrated sensing capability over a 60 km standard single-mode fiber.
• Obtained a temperature resolution of 1.2°C and a strain resolution of 24 με.

Conclusions:

• The optimized DPP-BOTDA system with optical pre-amplification and pulse coding significantly advances distributed fiber sensing.
• This approach enables high-resolution, long-range measurements previously unattainable.
• The findings pave the way for more precise structural health monitoring and other fiber-optic sensing applications.