Multiplexed fiber-ring laser sensors for ultrasonic detection

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Sensors
• Laser Technology

Background:

• Multiplexing fiber Bragg grating (FBG) sensors is crucial for efficient ultrasonic detection.
• Existing methods face challenges like mode competition, limiting simultaneous demodulation.
• Integrating FBG sensors within a laser cavity offers potential for novel multiplexing strategies.

Purpose of the Study:

• To propose and demonstrate a novel multiplexing method for ultrasonic sensors based on FBGs.
• To achieve simultaneous demodulation of multiple FBG ultrasonic sensors.
• To avoid mode competition in fiber-ring laser systems for enhanced sensing.

Main Methods:

• Utilized a fiber-ring laser with integrated fiber Bragg gratings (FBGs) as ultrasonic sensors.
• Employed add-drop filters to wavelength-division multiplex (WDM) light signals.
• Routed wavelength-specific signals into separate optical paths, each with an erbium-doped fiber (EDF) gain medium.

Main Results:

• Successfully demonstrated a two-channel multiplexing system with two sensing FBGs.
• Achieved simultaneous demodulation of FBG ultrasonic sensors without mode competition.
• Showcased the effectiveness of routing wavelength signals to dedicated EDF spans.

Conclusions:

• The proposed multiplexing method enables efficient and simultaneous demodulation of FBG ultrasonic sensors.
• Integrating FBGs within a laser cavity and using add-drop filters offers a robust solution for ultrasonic sensing arrays.
• This technique avoids mode competition, paving the way for advanced fiber optic sensing applications.