Abstract:In this paper, we propose and numerically characterize the optical characteristics of a high sensitivity dual polarization four channels surface plasmon resonance refractive index sensor with wide detection range and high linearity based on photonic crystal fiber (PCF). Four light transmission channels are constructed by using big air holes. The small rectangular air hole in the center of the fiber core is used to add asymmetry. We use gold plasma material to achieve better sensing performance. A thin film of TiO2 is placed on the PCF surface, which assists gold in the adhesion on PCF. The maximum wavelength sensitivity of the sensor can reach 20000 nm/RIU in both x and y polarization modes. While the maximum wavelength resolution of the sensor is 5×10-6 RIU. The average wavelength sensitivity reached 15900nm/RIU and 15800nm/RIU in x and y polarization mode. The sensor features R2=0.9969 / R2=0.9966 high linear performance in x and y polarization mode and the maximum FOM values 509.13 RIU-1 / 489.63 RIU-1 in x and y polarization mode. Besides the sensor’s detection range is 1.26-1.36, which is a wide refractive index detection range. The sensor has a wide range of applications in biomedical and other fields.