we uv inscribe and characterize a long-period fiber grating with a period of 25 mu m. a series of polarization-dependent dual-peak pairs can be seen in the transmission spectrum, even though only the symmetrical refractive index modification is introduced. the fabricated grating exhibits a lower temperature sensitivity compared with standard long-period gratings and an enhanced refractive index sensitivity of similar to 312.5 nm/riu averaged from 1.315 to 1.395, which is more than four-fold higher than standard long-period gratings in this range. the full width at half-maximum of the fabricated grating is only about 0.6 nm, allowing for high-resolution sensing. moreover, the grating period is so small that the attenuation dip corresponding to a high-order bragg resonance can also be seen, which can act as a monitor of the unwanted perturbation to realize dual-parameter sensing. (c) 2017 optical society of america