Photonics Research Center, School of Electronic Engineering and Automation, Guilin University of Electronics Technology, Guilin, 541004, People's Republic of China.
Key Laboratory of In-Fiber Integrated Optics, Ministry of Education, College of Science, Harbin Engineering University, Harbin, 150001, People's Republic of China.
Sci Rep. 2017 Jul 12;7(1):5171. doi: 10.1038/s41598-017-05414-w.
A discrete optical system can broaden the spatial distribution of the input light through optical coupling in array waveguides, just like diffraction in continuous media. Here, we theoretically demonstrate several kinds of control methods of optical field propagation in a discrete optical system, which is composed of an Airy fiber with two perpendicular arrayed cores. A brief transform mechanism between Gaussian and Airy beam propagation in such a fiber is presented. The wavefront of the output beam from the Airy fiber is actually dependent on the phased arrayed modulation of coupling array cores. Except the optical wavelength changing, we propose two new methods, including fiber length and bending-induced refractive-index changing, to accomplish that modulation. The calculation results show that these new methods are very effective for the Airy phase modulation. By combining these methods and controlling the corresponding parameters, the Gaussian beam, the one-dimension Airy beam, and the two-dimension Airy beam can be obtained by one same Airy fiber. These methods are also generally applicable to the other discrete optical system and can be extended to generate any other types of optical beams, such as Bessel beams and Mathieu beams.
离散光学系统可以通过阵列波导中的光学耦合来扩展输入光的空间分布，就像在连续介质中的衍射一样。在这里，我们从理论上证明了几种控制离散光学系统中光场传播的方法，该系统由具有两个垂直排列的芯的艾里光纤组成。介绍了这种光纤中高斯光束和艾里光束传播之间的简要变换机制。艾里光纤输出光束的波前实际上取决于耦合阵列芯的相位阵列调制。除了改变光学波长外，我们还提出了两种新方法，包括光纤长度和弯曲诱导折射率变化，以实现这种调制。计算结果表明，这些新方法对艾里相位调制非常有效。通过结合这些方法并控制相应的参数，可以通过同一根艾里光纤获得高斯光束、一维艾里光束和二维艾里光束。这些方法也普遍适用于其他离散光学系统，并可扩展到生成任何其他类型的光束，如贝塞尔光束和马休光束。
