Birefringent Bragg Grating in C-Shaped Optical Fiber as a Temperature-Insensitive Refractometer

Area of Science:

• Optics and Photonics
• Materials Science
• Sensor Technology

Background:

• Optical fiber sensors are crucial for various applications.
• Traditional refractometers often suffer from cross-sensitivity to environmental factors like temperature.
• Developing robust and sensitive refractive index sensors remains an active research area.

Purpose of the Study:

• To demonstrate a simple-to-fabricate refractometer.
• To utilize a specially designed C-shaped optical fiber for sensing.
• To achieve high sensitivity and overcome temperature cross-sensitivity issues.

Main Methods:

• Fabrication of a C-shaped optical fiber by machining a preform of a commercial single-mode fiber.
• Inscription of fiber Bragg gratings within the C-shaped optical fiber.
• Characterization of the sensor's response to changes in refractive index and temperature.

Main Results:

• Successfully fabricated a refractometer based on fiber Bragg gratings in C-shaped optical fiber.
• Achieved a high refractive index sensitivity of 1300 pm per refractive index unit (RIU).
• Demonstrated no cross-sensitivity to ambient temperature fluctuations.

Conclusions:

• The proposed C-shaped optical fiber refractometer is a simple and effective sensing device.
• The sensor exhibits excellent refractive index sensitivity and temperature stability.
• This technology holds promise for accurate refractive index measurements in diverse applications.