Multiplexed dynamic strain sensing system based on a fiber ring laser using a non-tunable fiber Fabry-Perot filter

Area of Science:

• Optoelectronics
• Fiber Optic Sensing
• Photonics

Background:

• Dynamic strain sensing is crucial for structural health monitoring.
• Existing methods often face limitations in frequency response or complexity.
• Multiplexed sensing systems offer advantages in scalability and coverage.

Purpose of the Study:

• To develop a simple, low-cost, and effective system for demodulating dynamic strain signals.
• To demonstrate the capability of a fiber ring laser sensor for ultra-high frequency strain detection.
• To explore multiplexing capabilities for enhanced sensing applications.

Main Methods:

• A non-tunable fiber Fabry-Perot filter (FFPF) was configured within a fiber ring laser cavity.
• A semiconductor optical amplifier (SOA) was used to enable multiplex operation via inhomogeneous broadening.
• Dynamic strain-induced shifts in a fiber Bragg grating's reflective spectrum were demodulated by the FFPF.

Main Results:

• The sensing system successfully demodulated dynamic strain signals at ultra-high frequencies up to the megahertz range.
• Ultrasonic signals in water were detected, demonstrating the system's practical applicability.
• A dual-channel system for multiplexing demodulation was designed and discussed.

Conclusions:

• The proposed fiber ring laser sensor system offers a simple structure and low cost.
• It is highly suitable for dynamic strain detection, particularly for ultrasonic signals.
• The system holds significant potential for structural health monitoring applications.