Single-measurement digital optical frequency comb based phase-detection Brillouin optical time domain analyzer

Area of Science:

• Optical sensing
• Fiber optic sensors
• Photonics

Background:

• Distributed Brillouin optical time domain analysis (BOTDA) is crucial for fiber optic sensing.
• Traditional BOTDA systems often require frequency scanning and data averaging, limiting response times.
• Faster sensing is needed for dynamic strain and vibration monitoring.

Purpose of the Study:

• To propose and demonstrate a single-measurement, sweep-free BOTDA sensor.
• To leverage digital optical frequency comb (DOFC) technology for enhanced performance.
• To achieve rapid response times for dynamic measurements.

Main Methods:

• Utilizing a digital optical frequency comb (DOFC) as the probe signal.
• Employing phase detection and coherent detection to measure the Brillouin Phase Spectrum (BPS).
• Performing single-acquisition measurements without frequency scanning or averaging.

Main Results:

• Demonstrated a single-measurement BOTDA sensor over a 10km fiber.
• Achieved a rapid response time of 100 μs, limited by fiber length.
• Obtained a spatial resolution of 51.2m and a Brillouin frequency shift (BFS) uncertainty of ~1.5 MHz.
• Successfully demonstrated dynamic measurements up to 1 kHz vibration frequency.

Conclusions:

• The proposed single-measurement BOTDA sensor offers a significant advancement in sensing speed.
• DOFC-based phase detection enables fast, high-resolution, and accurate distributed fiber sensing.
• This technology is well-suited for dynamic strain and vibration monitoring applications.