Application Research Of Photonic Crystal Fiber In Splitter And Sensor

Since the advent of the photonic crystal fiber(PCF)in twentieth Century,it has been widely used in optical communication and optical devices because of the flexibility of its design and excellent optical properties.In this paper,the application of PCF in the beam splitter and sensor is studied.A single-polarization single-mode splitter based on PCF has been designed,and the characteristics of the splitter are analyzed.The unfilled and liquid-filled PCF sensors are designed.The sensing characteristics of the PCF sensors are studied through the experiments.Main contents include:1.The characteristics,classification and applications of PCF are summarized,and the application of PCF in the beam splitter and sensor is summarized.2.This paper introduces the methods of the numerical study of the PCF,and the relevant principles of the PCF splitter and the PCF sensor are summarized.3.A single-polarization single-mode PCF splitter is designed.Using the full vector finite element method,numerical investigations demonstrate that the wavelengths of 1.3?m and 1.55?m are split for a fiber length of 1.67 mm with single-polarization guiding in each core.At 1.55?m and 1.3?m,the crosstalks can reach-41dB/m and-35dB/m.Around the wavelengths of 1.3?m and1.55?m,when the crosstalk is lower than-20 dB,the crosstalk bandwidths can reach 25 nm and 35 nm in the x-polarization direction,respectively.The single-polarization single-mode photonic crystal fiber splitter has short length and low crosstalk,and the same time it can effectively inhibit the polarization coupling and polarization dispersion.4.Sensors of two structures based on PCF are designed.The one is a PCF sensor based on spherical structure and offset-core structure,and the other is a PCF sensor based on two spherical structures.The temperature and refractive index are measured by the PCF sensor based on spherical structure and offset-core structure.When the temperature changes from 25? to 75?,the wavelength shifts from 1531.56 nm to 1531.96 nm.When the refractive index changes from 1.335 to 1.37,the corresponding wavelength shifts from 1528.06 nm to 1534.72 nm.The experimental results show that the temperature and refractive index sensitivities can reach 8.13pm/?and 188.09nm/RIU,respectively.The temperature and refractive index are measured by the PCF sensor based on two spherical structures.When the temperature changes from 25? to 75?,the wavelength shifts from 1545.45 nm to 1545.96 nm.When the refractive index changes from 1.335 to 1.37,the corresponding wavelength shifts from 1550.89 nm to 1557.58 nm.The experimental results show that the temperature and refractive index sensitivities can reach 9.09 pm/? and 195.42nm/RIU,respectively.5.In order to improve the temperature sensitivity of the sensor,the sensor is filled with ethanol,and the photonic crystal fiber sensor of the same structure based on two spherical structures is fabricated.The temperature and refractive index are measured.When the temperature changes from 26? to 44?,the corresponding wavelength shifts from 1551.02 nm to 1536.22 nm.When the refractive index changes from 1.34 to 1.37,the corresponding wavelength shifts from 1525.95 nm to 1530.11 nm.The experimental results show that the temperature and refractive index sensitivities can reach-0.802nm/? and 135.64nm/RIU,respectively.The experimental comparison shows that the temperature sensitivity of the filled sensor is improved,obviously.