大模场面积掺镱双包层光纤的色散测量

大模场面积掺镱双包层光纤的色散特性在高功率超连续谱的产生中具有重要影响。搭建了一套基于马赫-曾德尔干涉仪和超连续谱光源的超宽波段、高精度的色散测量系统。干涉仪的测量臂插入待测光纤，参考臂通过高精度步进电机调节光程。通过此系统，仅使用27.2 cm长的样品对大模场面积掺镱双包层光纤的色散特性进行了精确测量。实验记录了700~1 600 nm范围内不同波长的干涉条纹，计算得到光纤的色散曲线。使用全矢量有限元法对光纤的色散进行了数值模拟，模拟结果与实验结果一致，证明了实验方法与系统的精确性。

Dispersion measurement of large mode area Yb-doped double-clad fiber

Dispersion properties play a key role in high power supercontinuum generation in large mode area Yb-doped double-clad fiber. In this paper, an improved ultra-broadband and high resolution dispersion measurement system, based on a Mach-Zehnder interferometer and supercontinuum, was set up. The test arm of the interferometer was inserted with the fiber under test, and the reference arm of adjustable optical path length was tuned by a computer-controlled stepper motor with high resolution. The accurate dispersion characteristics of large mode area Yb-doped double-clad fiber was measured with a very short length of 27.2 cm. A series of interferometric fringes of different wavelengths, over a wide spectral range from 700 nm to 1 600 nm, were recorded to calculate the dispersion curve. Numerical calculation of the dispersion by finite element method was also made. The test results are in great agreement with numerical calculation, which shows good performance of the method and experimental system.