A Magnetic Field Sensor Based on Directional Coupling in a Magnetic Fluid-Filled Photonic Crystal Fiber

Area of Science:

• Photonics
• Sensor Technology
• Materials Science

Background:

• Dual-core photonic crystal fibers (DC-PCFs) offer unique light manipulation properties.
• Magnetic fluids exhibit tunable optical properties in response to external magnetic fields.
• Developing sensitive and compact magnetic field sensors is crucial for various applications.

Purpose of the Study:

• To introduce and investigate a novel dual-core photonic crystal fiber (DC-PCF) sensor.
• To explore the use of magnetic fluid for tunable optical sensing.
• To assess the sensor's performance for magnetic field detection.

Main Methods:

• Finite Element Method (FEM) simulations were employed for sensor design and analysis.
• A DC-PCF structure was designed with magnetic fluid filling the interstitial pore.
• The influence of external magnetic fields on the magnetic fluid's refractive index and its effect on light coupling was modeled.

Main Results:

• A strong linear relationship was observed between the dip wavelength and magnetic field strength (80-260 Oe).
• The sensor achieved a high magnetic field detection sensitivity of 515.75 pm/Oe.
• The magnetic fluid-filled hole was utilized for modulation, not energy transmission, minimizing loss.

Conclusions:

• The developed magnetic fluid-filled DC-PCF sensor exhibits high sensitivity and a small footprint.
• The sensor's design effectively leverages the tunable refractive index of magnetic fluids.
• This technology holds significant potential for magnetic field sensing in medical and industrial fields.