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A novel side-polished long-period fiber grating (LPFG) sensor was proposed and experimentally validated. Side-polished can provide a stronger evanescent field than traditional grating and bring superior sensitivity. The greater the side-polished depth, the higher the refractive index (RI) sensitivity. When d = 44 μm, the refractive index sensitivity reached 466.85 nm/RIU in the range of 1.3330 -1.3580, which is four-fold higher than LPFG prepared by electric-arc discharge (EAD) method. A graphene oxide (GO) nano-film is coated on the LPFG to make it realize high sensitivity relative humidity (RH) sensing. Humidity sensitivity reached -0.193 nm/%RH in the range of 40 -80% RH. In addition, sidepolished breaks the symmetry of the distribution of the crosssectional light field, which determines the ability to achieve vector curvature measurement. It shows good sensing performance in the same/opposite bending direction as the side polished surface. When the input light polarization is 90°, the average sensitivity reaches 5.03 and -5.9 nm/m -1 in the range of 0 -19.67 m -1 , respectively. This strongly indicates that the fabricated sensors show high sensitivity, low-cost materials, and robust performance and break the limitations of the EDA method to prepare gratings, which have good application potential for biomedicine and the field of construction.

A microfiber sensor detecting Ni2+ based on ion imprinting technology was fabricated and the sensor possessed high sensitivity, a low limit of detection and good regeneration.

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