Research On The Sensing Characteristics Of Microfluidic Photonic Crystal Fiber

With the increasing maturity of optical fiber technology,optical fiber has been widely used in optical communication,optical devices,nonlinear optics and other fields.As one of the important branches of optical fiber technology,optical fiber sensor has received extensive attention because of its small size,light weight,fast response speed,anti-electromagnetic interference and other advantages.However,it also faces the impact of cross-sensing,sensing sensitivity,structural fragility and other problems.This paper presents a photonic crystal fiber sensing system based on microfluidic,which can also be an optical fluidic system.The system makes use of the microchannel of the photonic crystal fiber itself and the fast response of the fiber to complete the structure preparation or sample detection under the condition of continuous flow of microvolume samples.The main research contents of this paper are as follows:(1)A liquid filled photonic crystal fiber temperature sensor is studied.The photonic crystal fiber(PCF)was filled with a matching solution of 1.45 refractive index by a syringe pump and fused between two single-mode fibers to measure the projection spectra of the structure at different temperatures.The experimental results show that the optical fiber can be converted from total reflection guided fiber to band-gap fiber with temperature change.The temperature variation is linear from 30 ? to 60 ?,and the sensitivity is as high as 7.88 nm/?,indicating that the photonic crystal fiber sensing performance is good.(2)A new microfluidic coupled photonic crystal fiber system with integrated photochemical technology is proposed,which is a new technology for comprehensive analysis of photochemical reactions.Through the calculation of optical fiber parameters,the selection of lens combination and the investigation and design of microfluidic devices,an optical fluidic system was built.The photochemical reaction products can be monitored online by high resolution mass spectrometry,which can not be achieved through the test tube based experiment.It can improve the response speed of the optical fiber sensor,the flexibility of drug entry and exit,and the ability of experiment repeatability.The system is built by calculating the optical fiber parameters and selecting the lens combination.It can be used for sample preparation,separation and analysis in a direct way or for the measurement of sensitive flow in microstructural systems.The combination of low volume microcurrent and high optical intensity continuous current circuit in photonic crystal fiber makes this method much less sampling and less time consuming than the analysis method based on test tube.(3)The fusion type on-line optical flow control system is designed.The system is easy to be coupled without the need of lens and displacement platform for spatial optical operation.The structure is compact and independent.An opening is created in the quartz capillary as a channel for fluid to enter and exit the system by means of a fiber-optic sidetracking machine or femtosecond laser micromachining.Using silver mirror reaction,silver plating film was tested in capillary tube through microfluidic channel.It is found that the refractive index sensitivity and temperature sensitivity of quartz capillary capillary are improved by comparing the samples before and after coating with different lengths and inner diameters.