Wavelength Modulated Anti-Resonant Fiber-Optic Microfluidic Device Based on SMF-HCTF-SMF Structure

A wavelength modulated microfluidic device based on hollow core tube fiber (HCTF) is proposed, the modal dispersion and field distributions of the liquid-filled HCTF are analyzed and simulated based on the anti-resonant mechanism, and refractive index and temperature sensing performances are demonstrated. The device is formed by the single mode fiber-HCTF-single mode fiber structure, and there are two micro-slots at the fiber fusion joints for liquid flow through the HCTF. Comparative experiments show that the device can be immersed in liquid environments, which is difficult for the structure without micro-slots. Various devices with different HCTF inner diameters and lengths are fabricated, according to the anti-resonant mechanism, the non-transmission wavelength position, free spectrum range, and spatial frequency of the spectrum are discussed. Besides, the sensing performances of the microfluidic device with different structural parameters are also tested and compared, the experimental results are consistent with the theoretical analysis. This comparative study of the HCTF-based microfluidic element is instructive for the investigation of other kinds of anti-resonant structures. Moreover, the proposed microfluidic device is a promising biochemical sensor with a compact structure, high reliability, and ultra-sensitivity.