Sampled fiber Bragg grating for simultaneous refractive-index and temperature measurement.

Area of Science:

• Photonics and Optical Sensing
• Materials Science
• Analytical Chemistry

Background:

• Accurate simultaneous measurement of temperature and refractive index is crucial for various scientific and industrial applications.
• Existing methods often require multiple sensors or complex setups, limiting their practicality.
• Sampled Fiber Bragg Gratings (SFBGs) offer unique spectral properties that can be leveraged for multi-parameter sensing.

Purpose of the Study:

• To develop and demonstrate a novel sensing scheme for simultaneous temperature and refractive index measurement.
• To utilize the distinct spectral responses of a single SFBG for independent parameter extraction.
• To validate the sensor's performance by measuring the temperature dependence of sucrose solution refractive index.

Main Methods:

• A single Sampled Fiber Bragg Grating (SFBG) was employed as the sensing element.
• The Fiber Bragg Grating (FBG) spectral response was used to isolate temperature information.
• The Long-Period Grating (LPG) spectral response was utilized to extract refractive index data.
• The sensor's capability was demonstrated by analyzing an aqueous sucrose solution.

Main Results:

• The proposed scheme successfully enabled simultaneous measurement of temperature and refractive index using a single SFBG.
• Temperature variations were accurately determined from the FBG spectral response.
• Refractive index changes were reliably extracted from the LPG spectral response.
• The temperature dependence of the refractive index for a sucrose solution was successfully quantified.

Conclusions:

• A novel and effective dual-parameter sensing approach using a single SFBG has been presented.
• This method allows for independent and simultaneous measurement of temperature and refractive index.
• The demonstrated application highlights the potential of SFBGs in advanced optical sensing systems.