Surface Plasmon Resonance Refractive Index Sensor Based on Active Photonic Crystal Fiber

We propose a surface plasmon resonance (SPR) refractive index (RI) sensor based on an active Yb3+-doped photonic crystal fiber (PCF) in this paper. With the proposed sensor, using the pump light at 976 nm can produce laser at 1060 nm. In addition, the sensitivity can be influenced obviously by a bit change of the refraction index of analyte in the air holes to achieve the intra-cavity fiber sensing. It is found that not only the different air-filling ratios but also the different analyte RIs of n(a) > 1.45 or n(a) < 1.45 have different effects on the output power and confinement loss, and lead to different trends. The intra-cavity PCF sensing system has great practical value and significance for their advantages of compact structure and high sensitivity.