Using pulse with a dark base to achieve high spatial and frequency resolution for the distributed Brillouin sensor

Area of Science:

• Optoelectronics
• Fiber Optic Sensing
• Photonics

Background:

• Distributed optical fiber sensors are crucial for monitoring physical parameters.
• Stimulated Brillouin scattering (SBS) is a key technique in fiber sensing.
• Limitations exist in achieving high spatial and frequency resolution with conventional SBS methods.

Purpose of the Study:

• To propose a novel distributed optical fiber sensor for enhanced spatial and frequency resolution.
• To introduce a new probe pulse shape for improved Brillouin spectrum analysis.
• To enable accurate detection of small stress or temperature variations in optical fibers.

Main Methods:

• Utilizing a stimulated Brillouin scattering (SBS) based distributed optical fiber sensor.
• Employing a probe pulse with finite extinction ratio (ER) and a dark base.
• Analyzing the Brillouin spectrum to detect changes in Brillouin frequency shift (BFS).

Main Results:

• The proposed sensor achieves higher spatial and frequency resolution for stress and temperature detection.
• A novel pulse shape effectively reduces the peak height of the Brillouin spectrum at stress points.
• Experimental results demonstrate centimeter-level stress/temperature section measurement with low BFS uncertainty (0.9 MHz for 5 cm sections).

Conclusions:

• The novel pulse shape significantly enhances the performance of SBS-based distributed optical fiber sensors.
• This technique allows for precise measurement of localized stress and temperature changes.
• The study paves the way for more accurate and high-resolution fiber optic sensing applications.