Analysis and Improvement of a Dual-Core Photonic Crystal Fiber Sensor.

Pibin Bing,Jialei Sui,Hua Wang,Zhiyong Wang,Shichao Huang

doi:10.3390/s18072051

Pibin Bing, Jialei Sui + Show 3 more

Open Access

https://doi.org/10.3390/s18072051

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Abstract

The characteristics of the dual-core photonic crystal fiber (PCF) sensor are studied using the finite element method (FEM), and the structure is improved according to the numerical simulation results. The results show that whether or not the four large air holes far away from the geometry center of the PCF are filled with analyte has no influence on the wavelength sensitivity of the sensor which means those holes can be replaced by small air holes. The wavelength sensitivity can be tuned by adjusting the sizes of the other large air holes which are as for liquid holes. The dynamic detection range of the refractive index (RI) is from 1.33 to 1.51. In particular, high linearity is obtained in the range of 1.44 to 1.51. The sensitivity is as high as 6021 nm/RIU when the liquid holes are the smallest. When liquid holes are tangential with the envelope of first layer air holes, the wavelength sensitivity is 4028 nm/RIU, and the coefficient of determination (R2) is 0.99822 when the RI of the analyte varies from 1.44 to 1.51 which shows that high sensitivity and good linearity are both obtained.

Highlights

The surface plasma is excited on the surface of the metal–dielectric interface which is exceedingly sensitive to changes in the refractive index (RI) of the analyte
Sensors with D-shaped structures, such as air holes arranged in hexagons [4,5] or rectangules [6], central holes filled with high RI liquid [7] and photonic crystal fiber (PCF) plated with indium tin oxide at near-infrared wavelength [8,9] have been studied in recent years
Three-holed PCF coated with an auxiliary dielectric layer and gold film makes analyte filling easy [15]

Summary

Introduction

The surface plasma is excited on the surface of the metal–dielectric interface which is exceedingly sensitive to changes in the refractive index (RI) of the analyte. Three-holed PCF coated with an auxiliary dielectric layer and gold film makes analyte filling easy [15] All of these sensors are not applicable for the detection of high RI. It can be considered that they undergo energy exchange the B holes (B1–B4 in Figure 1) is d1 , the diameter of the A holes (A1–A6 in Figure 1) is d2 , and the intensively at point e and the anti-crossing effect takes place; this is known as complete coupling. It can beofconsidered that theyresonance undergo energy at point e and theabsorption anti-crossingpeaks effect change takes place; this is RI known completeThe coupling It can gold intensively film and the analyte.

Results and Discussion

Fundamental mode profiles analyteRIs

Conclusions