细径保偏光纤耦合器熔融拉锥制造技术的研究

发布时间：2018-02-13 10:47

  本文关键词： 细径保偏光纤耦合器 熔融拉锥 高精度对轴 蠕变建模 拉力控制　出处：《哈尔滨工业大学》2015年博士论文　论文类型：学位论文

【摘要】：保偏光纤耦合器是应用保偏光纤制作的光纤耦合器,是实现线偏振光耦合、分用以及复用的关键器件,是组成光纤陀螺的重要器件。在保偏光纤器件制造中采用细径光纤不仅可以减小器件体积,增加光纤陀螺的集成化程度,降低生产成本和光纤温度敏感,而且能够提高光纤陀螺的性能。采用细径保偏光纤是光纤器件发展的重要趋势,因而研究细径保偏光纤耦合器的制造具有重要意义。随着光纤直径向几十微米尺寸延伸,不利于光纤对轴和熔融拉锥的很多特性突显,例如光纤易于弯曲扭转、强度降低和几何尺寸减少等,并且熔融拉锥过程对各物理量的控制要求更加精密,因而对保偏光纤对轴和熔融拉锥过程中拉力、温度和速度等各物理量的控制提出了更高的要求。本文对细径保偏光纤耦合器熔融制造中的关键技术进行研究,从细径保偏光纤的高精度对轴、熔融拉锥蠕变建模、拉力控制及加热方式等四个方面进行深入研究,并且最后在此基础上建立细径保偏光纤耦合器制造实验平台。在保偏光纤高精度对轴方面,建立细径保偏光纤的折射率模型,利用有限元软件对细径保偏光纤的侧向成像进行仿真,通过对仿真结果分析选择焦点附近的最大光强变化检测保偏光纤的偏振轴。提出一种光纤与电动平台旋转中心同轴度的调节方法,经图像处理得到光纤图像的轮廓,采用最小二乘法计算出光纤中心的直线方程,得到光纤中心与电动旋转中心的距离。采用基于阈值的图像清晰度函数,确定显微镜检测的位置,然后将采集的数据进行傅里叶滤波和三次样条拟合,得到保偏光纤偏振轴的位置。在光纤熔融拉锥蠕变建模方面,光纤熔融拉锥的过程是光纤蠕变的过程,分析粘弹性材料的玻璃化温度及假定温度、力学性能以及简单热流变特性。通过拉伸实验测得光纤的玻璃化温度,采用广义Maxwell模型描述光纤材料在变温下的应力松弛。测量光纤材料的蠕变恢复曲线,以迟缓矩为约束条件,采用有条件最优化搜索求解光纤材料的迟缓模量系数和迟缓时间,建立迟缓模量与松弛模量的关系,得到松弛模量系数和松弛时间。由松弛模量和蠕变柔量的卷积关系建立光纤的蠕变模型,对两个温度的蠕变模型数值求解,最后建立光纤蠕变和蠕变速率模型。在光纤熔融拉锥拉力控制技术方面,设计保偏光纤熔融拉力控制装置。该控制装置由计算机、拉伸机构、圆光栅和电磁力控制电路等组成,通过检测光纤支架的旋转角度,改变线圈中的电流,实现对拉伸力的实时控制。建立拉伸机构的三维空间模型,计算永磁铁的空间运动轨迹,对永磁铁和线圈之间的电磁力进行三维有限元仿真,从理论仿真验证该控制方法。设计电磁力的控制电路,建立拉力和电磁力的关系,最后通过实验建立线圈中的电流、支架旋转角度和光纤支架拉力的关系,实现熔融拉锥过程的拉力控制。最后,建立细径保偏光纤耦合器制造平台。对细径保偏光纤耦合器的制造工艺进行研究,设计一个采用高压电弧的加热源,采用电压闭环和电流控制,通过电弧控制电压控制电弧放电电流。采用红外热像仪对弧区温度进行测量,建立弧区温度与放电频率、电弧控制电压和加热距离的关系,检测高压电弧的最高温度及其加热稳定性。利用有限元方法对熔融拉锥前进行预热分析。设计了光纤夹持夹具,研究熔融拉锥速度的控制策略和消光比测试光路,最后制造出非匹配型细径保偏光纤耦合器。
[Abstract]:Polarization maintaining fiber coupler is used polarization preserving coupler production, is the realization of linear polarization coupling, and with key component reuse, is an important component of fiber optic gyro. In polarization maintaining fiber device fabrication using fine fiber can not only reduce the size of the device and increase the degree of integration of fog, reduce the production cost and the optical fiber temperature sensitive, and can improve the performance of fiber optic gyroscope. Small diameter polarization maintaining fiber is an important trend of development of the optical fiber device, which is of great significance to study fine diameter polarization maintaining fiber coupler manufacturing. With the diameter of fiber extending to tens of microns in size, is not conducive to highlight the many properties of fiber on axis and fused taper for example, easy to fiber bending torsion, reduce the strength and size reduction, the stretching process and the melting control of each physical quantity requires more precision, thus the polarization maintaining The fiber axis and the melt tension cone process, put forward higher requirements to control the temperature and the speed of the physical quantity. In this paper, the key technology of fine polarization maintaining fiber coupler in the manufacture of melt, from fine polarization maintaining fiber of high precision shaft, FBT creep modeling, four pull control and heating mode are studied deeply, and finally on the basis of the establishment of small diameter polarization maintaining fiber coupler manufacturing experiment platform. In polarization maintaining fiber in high precision shaft, a fine polarization maintaining fiber refractive rate model of fine polarization maintaining fiber lateral imaging are simulated using the finite element software. Through the analysis of simulation results to select the maximum intensity near the focus of inspection and polarization maintaining fiber axis. A fiber optic and electric platform rotation center coaxiality adjusting method, obtained by image processing of optical fiber image contour, By using the least squares method to calculate the linear equation of the center of the optical fiber, fiber center and the center of rotation of the electric distance. The image sharpness function based on the threshold to determine the microscope detection position, then the data will be collected by Fu Liye filter and three spline fitting, get the optical fiber polarization axis position. The coupler creep modeling, process of optical fiber fused fiber is the process of creep analysis, the glass transition temperature of the viscoelastic material and assumed temperature, mechanical properties and thermal rheological properties. The glass transition temperature by tensile test of optical fiber, the generalized Maxwell model to describe the stress relaxation in the temperature of the fiber material. Creep measurement fiber material recovery curve, with slow moment constraints, using the condition of optimal search solution for fiber material retardation coefficient and modulus of slow time, construction The relationship between vertical delay modulus and relaxation modulus, relaxation modulus coefficient and relaxation time. Creep model is established by the optical convolution relationship between relaxation modulus and creep compliance and creep model of numerical solution of two temperature, finally establish fiber creep and creep rate model. In the optical fiber taper tension control technology. Design of polarization maintaining fiber melt tension control device. The control device is composed of a computer, drawing mechanism, circular grating and electromagnetic force control circuit, through the rotation angle detection optical fiber bracket, change the current in the coil, to realize the real-time control of tensile force. Establish 3D model drawing mechanism, calculating the space trajectory of permanent magnet the three-dimensional finite element simulation of the electromagnetic force between the magnet and the coil, the control method is verified from simulation. The design of control circuit of the electromagnetic force and electromagnetic force was established 鍔涚殑鍏崇郴,鏈，

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