Abstract:A D-type SPR-PCF sensor is designed based on the principle of surface plasmon resonance. To effectively stimulate the SPR effect, a gold film is plated on the open-loop channel of the sensor. The structural parameters are fine-tuned and the sensing performance of the sensor are studied. The results show that the maximum spectral sensitivity reaches 18000 nm/RIU in the refractive index range of 1.24-1.32, and the maximum resolution is 5.56?10-6 RIU. The novel structure with high sensitivity and low refractive index provides a new perspective for fluid density detection