| In recent years,due to its unique advantages,such as low price,fast response speed,strong anti-interference ability,flexible and high stability,optical fiber has attracted extensive attention in the field of sensing and communication.The special stomatal arrangement of photonic crystal fiber can make it have the characteristics of high birefringence,low loss,low dispersion and flexible design,which has attracted much attention in the research of fiber sensing and fiber communication.In the field of optical fiber sensing,photonic crystal fiber makes use of the advantage of internal pores,and more and more photonic crystal sensors have been developed.Such as:humidity sensor,stress sensor,temperature sensor,refractive index sensor,etc.Subsequently,the combination of various new materials and optical fiber opens the door of diversified measurement for optical fiber sensing.Especially,magnetofluid,due to its unique magneto-optical characteristics and liquid phase state,can be easily combined with optical fiber and used as a hot dielectric material for optical fiber magnetic field measurement.In terms of optical fiber communication,facing the requirements of the information communication era with large capacity and high rate,photonic crystal fiber with miniaturization,high performance and low loss has become a hot research topic at present,which can realize the low-loss transmission of difficult transmission bands and broaden the application range of optical fiber transmission devices.In this paper,the properties of photonic crystals based on sensing and communication will be studied and discussed from the following aspects:Firstly,photonic crystals are briefly introduced,the research background,classification,application and research status at home and abroad are preliminarily understood,and the transmission mode theory.Secondly,a new photonic crystal was designed and its transmission characteristics in terahertz band were studied.Finite element numerical analysis method was used for simulation to analyze the effect of effective mode area and fiber core porosity on the transmission characteristics of effective material loss,limiting loss and power distribution fraction.The results show that in the single-mode transmission range of 0.5THz?0.85THz,zero dispersion,0.0532 high birefringence,effective material loss of 0.1157/cm and limiting loss as low as 1.47×10-4db/cm are achieved by introducing asymptotic rectangular array pores and elliptic holes into the fiber.This research can be used to manufacture polarized THz waveguide,filter,etc.It is of great significance to the new generation of terahertz waveguide to realize long distance and highly performance transmission.Finally,through the combination of overlying photonic crystals with magnetic,created a based on the magnetic fluid coating and intermittent cooling cone transmission type all fiber high sensitive magnetic field sensor,cone drawing process using intermittent pauses cooling technology,can be more convenient to obtain high quality interference spectrum,slow down the photonic crystal fiber air hole collapse,craft is simple,has strong maneuverability,high sensitivity,the advantages of the low loss,real-time online detection,and realizes the high sensitive magnetic field and the temperature effect on the sensor are discussed.The experimental results showed that when the length of the pull cone of PCF was 5.5mm and the diameter of the lumbar spine was 75um,it had good interference spectrum,and the sensitivity reached 95pm/Oe in the range of 0-78 Oe magnetic field,and the linear fitting degree was 98.31%. |
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