Side-Hole Microstructured Optical Fiber Integrative Twin-Microchannels for Optofluidic Sensing

Microstructured optical fiber (MOF) possesses unique capability of long interaction path-length between light and analyte samples, which shows distinct advantages in constructing in-line optofluidic sensing microchannel. In this paper, a side-hole MOF integrative twin-microchannels is proposed and experimentally demonstrated for optofluidic sensing application. The structure of in-line optofluidic microchannel consists of a side-hole MOF sandwiched between two sections of pre-processed microfiber, which is fabricated by utilizing ultrasonic vibration cutting and arc discharge splicing technology. For the optofluidic MOF, two microfluidic accesses allow liquids to flow in/out the cladding hollow holes, and enable optical waveguide signals to transmit through the microchannels simultaneously. Experimental results show that the optofluidic MOF achieves a sensing sensitivity of 1309.994 nm/RIU in the low refractive index (RI) range. Moreover, the proposed microfluidic approach provides an efficient strategy for solid-core-type MOF to load fluid liquids into their cross-sectional air holes for the study of light-matter interaction. Owing to the features of enhanced sensing performance and simplified microfluidic-system design, the side-hole MOF integrative twin-microchannels is well suitable for a wide range of optical sensing, filtering, bioimaging and micro-nano particle manipulation.