| Photonic quasi crystal fiber(PQF)is a new type of microstructure fiber based on photonic crystal fiber(PCF).It has more superior performance in nonlinear,mode area,flat dispersion,birefringence and so on.Because of its superior optical properties,it has a wide range of applications in many fields,such as optical devices,sensors,lasers and so on.For different needs,different kinds of PQF can be designed.By optimizing the optical fiber parameters,the optical fiber performance can become more superior.In this paper,three different types of HB-PQF are designed,and their structural parameters,optimization process and conclusion are introduced in detail.The influence of the change of relevant structural parameters on the birefringence characteristics is analyzed and summarized.The three kinds of HB-PQF are designed based on octet quasicrystal fiber,which mainly observe the birefringence at 1.55?m in the communication band.The influence of parameter change on birefringence is analyzed.The higher birefringence and lower confinement loss characteristics are obtained by optimizing the parameters.Firstly,a full circle air hole HB-PQF based on octahedral quasicrystal structure is designed.The structure is based on ZBLAN glass.The PQF maintains high birefringence transmission characteristics in the range of 1.3-1.8?m.the maximum birefringence value of the designed PQF in the communication band of 1.55?m is 4.1×10-2.In addition,Due to the use of circular air holes in the core and cladding,the PQF proposed in this design is relatively easy to manufacture.Secondly,a HB-PQF with spiral arrangement of cladding air holes is proposed.The designed PQF cladding consists of four air holes,each of which is composed of eight rotating symmetrical air holes.In the core area of the PQF,it consists of four symmetrical circular air holes and two horizontal arranged air holes The structure parameters of the ellipse are observed by optimizing the short axis size,the position of ellipse,the size and position of four air holes.The relationship between the birefringence increment and the position of the fiber cladding porosity is explored for the first time,and a method for obtaining the same birefringence with different wavelengths is proposed.Finally,a HB-PQF based on Ge20Sb15Se65 material with round air holes is proposed.The air holes used in the optical fiber are all round air holes.The main idea is to put an elliptical core in the designed optical fiber core,and add different sizes of air holes on the top,bottom,left and right of the elliptical core to make it tangent to the elliptical core,and then add air holes at the corresponding places to compress the mode field of the optical fiber to obtain higher birefringence.the maximum birefringence of 1.33×10-1can be obtained at 1.55?m of communication band.The confinement loss of the two polarization modes are less than 10-3and 10-6dB/m at 1.41-1.69?m of selected band,respectively. |
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