Temperature-compensated distributed refractive index sensor based on an etched multi-core fiber in optical frequency...

Area of Science:

• Optoelectronics
• Fiber Optics Sensing
• Chemical Sensing

Background:

• Distributed sensing requires precise measurement of physical parameters along an optical fiber.
• Environmental factors like temperature can interfere with refractive index (RI) measurements.
• Existing RI sensors may lack integrated temperature compensation, limiting accuracy.

Purpose of the Study:

• To develop a temperature-compensated distributed refractive index (RI) sensor.
• To utilize an etched multi-core fiber (MCF) for simultaneous RI sensing and temperature compensation.
• To demonstrate the sensor's capability in detecting dynamic processes like diffusion.

Main Methods:

• Fabrication of a multi-core fiber (MCF) sensor by etching to expose an outer core for RI sensing.
• Utilizing the inner core of the MCF for simultaneous temperature compensation.
• Employing optical frequency domain reflectometry (OFDR) for distributed sensing measurements.
• Experimental validation of RI sensing range and sensitivity, alongside temperature sensitivity.

Main Results:

• Achieved a sensing length of 19 cm and a spatial resolution of 5.3 mm.
• Demonstrated a wide RI sensing range from 1.33 to 1.44 refractive index units (RIU).
• Obtained a maximum RI sensitivity of 47 nm/RIU and a temperature sensitivity of 9.8 pm/°C.
• Successfully monitored the glycerol diffusion process in water.

Conclusions:

• The proposed etched MCF sensor effectively provides temperature-compensated distributed RI sensing.
• The sensor exhibits high sensitivity and a broad dynamic range, suitable for various applications.
• This technology enables real-time monitoring of diffusion processes and other RI-dependent phenomena.