Temperature-insensitive high-sensitivity refractive index sensor based on a thinned helical fiber grating with an...

Area of Science:

• Photonics
• Optical Sensing
• Fiber Optics

Background:

• Refractive index sensors are crucial for various applications.
• Traditional sensors often suffer from temperature sensitivity, limiting their accuracy.
• Enhancing sensitivity typically increases cross-talk and temperature dependency.

Purpose of the Study:

• To propose and demonstrate a novel temperature-insensitive, high-sensitivity refractive index sensor.
• To investigate the performance of a thinned helical fiber grating with an intermediate period (THFGIP).
• To suppress temperature-induced cross-talk effects in refractive index sensing.

Main Methods:

• Fabrication of a thinned helical fiber grating with an intermediate period (THFGIP).
• Experimental characterization of the sensor's response to surrounding refractive index (SRI) changes.
• Analysis of the sensor's temperature sensitivity and cross-talk suppression mechanisms.

Main Results:

• The proposed THFGIP sensor exhibits high SRI sensitivity, averaging 829.9 nm/RIU within the 1.3410-1.4480 RIU range.
• The sensor demonstrates low temperature sensitivity due to reduced waveguide dispersion.
• Effective suppression of temperature-induced cross-talk was achieved by decreasing the fiber grating diameter.

Conclusions:

• The THFGIP sensor offers a promising solution for accurate refractive index measurements.
• The sensor's design provides superior SRI sensitivity and temperature insensitivity.
• The simple structure, ease of fabrication, and low cost make it suitable for diverse SRI sensing applications.