Magnetic Fluid-Injected Ring-Core-Based Micro-structured Optical Fiber for Temperature Sensing in Broad Wavelength Spectrum

A highly sensitive temperature sensor of magnetic fluid (ethanol) using a ring-core-based microstructured optical fiber (MOF) with two large elliptical air holes beside the ring core has been suggested by the finite element method. Highly sensitive magnetic fluid ethanol is injected into the ring core to improve its high sensitivity response. The maximum sensitivity response of 25,641.025 nm/RIU and 10 nm/°C are obtained for the broad operating wavelength of 6500–7000 nm where the temperature range is 10–60°C and the applied magnetic field strength range is 50–200 Oe. Various parameters such as high birefringence, coupling length, power spectrum, transmission, and loss spectra were studied and 14 modes were analyzed in our work. The proposed structure can be further modified and applied in various applications, such as magneto-optic modulators, optical fiber gyroscopes, and switches. The reported MOF structure can easily be fabricated owing to its simplified structure and easy filling of functional materials.