Optical fiber strain sensor with high precision and extended dynamic range based on a coupled optoelectronic...

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Sensors
• Optoelectronics

Background:

• Traditional strain sensors face limitations in precision and dynamic range.
• Optoelectronic oscillators (OEOs) and mode-locked lasers offer unique properties for sensing applications.

Purpose of the Study:

• To propose and experimentally demonstrate a high-precision, extended dynamic range optical fiber strain sensor.
• To leverage the coupled optoelectronic oscillator (COEO) for strain measurement.

Main Methods:

• Integration of an OEO and a mode-locked laser into a single COEO system.
• Utilizing the frequency shift of the COEO, influenced by axial strain, for measurement.
• Employing higher frequency order harmonics to enhance sensitivity.

Main Results:

• Achieved a dynamic strain range of 10000 μɛ.
• Demonstrated sensitivities of 6.5 Hz/μɛ (960 MHz) and 13.8 Hz/μɛ (2700 MHz).
• Exhibited low frequency drift (±148.03 Hz at 960 MHz, ±303.907 Hz at 2700 MHz) corresponding to high measurement accuracy (±22 μɛ and ±20 μɛ).

Conclusions:

• The proposed COEO-based fiber optic strain sensor offers high precision and speed.
• The strain-dependent optical pulse period of the COEO enables potential applications in dynamic strain measurement.