新型高双折射微结构纤芯光子晶体光纤的可调谐超连续谱的特性研究

发布时间：2018-10-20 10:34

【摘要】：提出并制备了一种新型微结构纤芯光子晶体光纤,即在椭圆纤芯中增加一排亚微米级的空气孔,提高了光纤的双折射值,改变了两个偏振基模的色散特性.通过有限元法数值模拟了该光纤的双折射、非线性和色散等特性,并优化结构参数.使用脉宽为15 ps,重复频率为45 MHz的激光抽运该光纤,通过调节抽运激光入射的偏振方向,实现了可调谐的宽带超连续谱.实验研究了输入激光的功率和偏振方向对超连续谱的影响,以及输出超连续谱的偏振特性:当脉冲偏振方向沿着主轴入射时,得到了800—1500 nm的线偏振超连续谱,输出谱的消光比为21.2 d B;当脉冲偏振方向逐渐远离主轴时,输出超连续谱的谱宽逐渐变窄,并且在与主轴呈处达到最小值.维持抽运脉冲功率不变,仅改变脉冲入射的偏振方向,能够实现300 nm谱宽可调谐的超连续谱.
[Abstract]:A novel microstructured photonic crystal fiber is proposed and fabricated, in which a row of sub-micron air holes are added to the elliptical core, which improves the birefringence of the fiber and changes the dispersion characteristics of the two polarization base modes. The birefringence, nonlinearity and dispersion of the fiber are numerically simulated by finite element method, and the structural parameters are optimized. The fiber is pumped by a laser with a pulse width of 15 ps, and a repetition rate of 45 MHz. The tunable broadband supercontinuum spectrum is achieved by adjusting the polarization direction of the incident pumped laser. The influence of the input laser power and polarization direction on the supercontinuum spectrum and the polarization characteristics of the output supercontinuum spectrum are studied experimentally. When the pulse polarization direction is incident along the main axis, the linear polarization supercontinuum spectrum of 800-1500 nm is obtained. The extinction ratio of the output spectrum is 21.2 dB. When the polarization direction of the pulse is gradually away from the main axis, the spectral width of the output supercontinuum becomes narrower and reaches the minimum value at the main axis. By keeping the pump pulse power constant and changing the polarization direction of pulse incidence, the tunable supercontinuum spectrum with 300 nm spectral width can be realized.
【作者单位】：华中科技大学武汉光电国家实验室;
【基金】：国家自然科学基金(批准号:61535009)资助的课题~~
【分类号】：TN253

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