Optomechanical microbubble Fabry-Pérot interferometer for ultrasensitive curvature measurement

Area of Science:

• Optoelectronics
• Fiber Optics Sensors
• Micro-optics

Background:

• Conventional fiber-optic sensors often lack the sensitivity required for high-precision curvature monitoring.
• Existing Fabry-Pérot interferometer (FPI) sensors face limitations in modulation efficiency and wavelength sensitivity.

Purpose of the Study:

• To develop an ultrasensitive fiber-optic curvature sensor with enhanced performance.
• To leverage micro-optomechanical coupling (MOC) for improved optical-path-difference (OPD) modulation and wavelength sensitivity.

Main Methods:

• Fabrication of a micro-air-bubble Fabry-Pérot interferometer (MFPI) sensor.
• Integration of a micro-optomechanical coupling (MOC) mechanism using specially designed fiber tapers.
• Characterization of sensor performance under bending conditions.

Main Results:

• Achieved remarkable curvature sensitivity of -15.24 nm/m⁻¹ and intensity sensitivity of -15.31 dB/m⁻¹.
• Demonstrated sensitivity one to two orders of magnitude higher than conventional FPI sensors.
• Exhibited negligible temperature cross-sensitivity and good repeatability.

Conclusions:

• The novel MFPI sensor with MOC offers superior performance for high-precision curvature sensing.
• The sensor is well-suited for real-time monitoring in confined or thermally variable environments.
• Potential applications include soft robotics and steerable medical catheters.