Optical Fiber-Tip Sensors Based on In-Situ µ-Printed Polymer Suspended-Microbeams

• Main Authors: Mian Yao, Xia Ouyang, Jushuai Wu, A. Ping Zhang, Hwa-Yaw Tam, P. K. A. Wai
• Format: Article
• Language: English
• Published: MDPI AG 2018-06-01
• Series: Sensors
• Subjects: optical fiber-tip sensors; optical 3D µ-printing; refractive index sensors; gas-pressure sensors; lab-on-fiber
• Online Access: http://www.mdpi.com/1424-8220/18/6/1825

Miniature optical fiber-tip sensors based on directly µ-printed polymer suspended-microbeams are presented. With an in-house optical 3D μ-printing technology, SU-8 suspended-microbeams are fabricated in situ to form Fabry–Pérot (FP) micro-interferometers on the end face of standard single-mode optical fiber. Optical reflection spectra of the fabricated FP micro-interferometers are measured and fast Fourier transform is applied to analyze the cavity of micro-interferometers. The applications of the optical fiber-tip sensors for refractive index (RI) sensing and pressure sensing, which showed 917.3 nm/RIU to RI change and 4.29 nm/MPa to pressure change, respectively, are demonstrated in the experiments. The sensors and their optical µ-printing method unveil a new strategy to integrate complicated microcomponents on optical fibers toward ‘lab-on-fiber’ devices and applications.