Conventional optical fiber made from extremely pure silica glass has become a real wonder in human history. However, even such a high level of performance of silica fiber is not yet good enough. Myriad applications flowing out from heads of scientists and engineers, who want higher laser power, more sensitive environmental detection, multiple fiber cores, higher/lower nonlinearities, higher/lower birefringence, more thermal stability, and widely engineerable dispersion landscapes … , constantly urge optical fibers into more versatile forms.

By increasing the difference of refractive indices of composite materials by up to 2 orders of magnitude and adopting light guidance's other than Total Internal Reflection, Micro-structured Optical Fibers (MOFs, or Photonic-Crystal Fibers) have opened an efficient route to gain these versatilities. Since Prof. Philip Russell opened this door in 1991, the exploration has lasted for more than 30 years.

Probably, the most fascinating achievement of MOF is to realize long-distance light propagation in a hollow (air) core, which was, at the beginning, enabled after Philip Russell, Jonathan Knight, and Tim Birks discovering Photonic Band-Gap (PBG) guidance and had recently reached a record attenuation of 0.28dB/km after the community (including us) unveiling advanced Anti-Resonant Reflecting mechanism. In this field, our group will aim at the next milestones of surpassing various long-haul transmission properties of Hollow-Core Anti-Resonant Fibers over silica glass fibers.

On the other hand, the magic of MOF is also embodied in the unprecedented characteristics of endless single-mode, largely engineerable dispersion, large mode field area, strong nonlinearity, strong birefringence, etc. of the solid-core fiber form. Benefitting from the flexibility of stack-and-draw fabrication approach, these novel solid-core MOFs have greatly expanded the scope of fiber optics. Relying on excellent facilities, experiences, and theoretical analyses, our group will focus on the research of design and fabrication of novel solid-core MOFs.

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作为当今世界信息化时代支柱技术之一的石英玻璃光纤，以其极纯净的材料成分和极优化的拉制工艺闻名于世。然而，即使是这样一项顶级的工业技术，面对人类社会层出不穷的新任务新要求时，仍然感到了力不从心。当人们需要光纤提供更高功率的激光、更灵敏的环境感知、更密集的纤芯、更强（弱）的非线性效应、更强的偏振保持能力、更优良的热稳定性、更大范围可调的色散能力等新奇性能的时候，对新光纤的追求就一刻也没有停止过。

由石英玻璃和空气组成的微结构光纤（也叫光子晶体光纤）能够获得人类前所未见的新的光学性能，这主要归因于如下两项基本特征：1）微结构光纤中的材料折射率差比传统掺杂光纤高两个数量级，可以对光波进行更剧烈的操控；2）微结构光纤的包层区域中存在着复杂的光波干涉现象，带来了迥异于传统“全内反射”效应的新的导光机制。自从Philip Russell教授1991年开创光子晶体光纤领域以来，人们对这类光纤的探索持续了三十余年。

或许，微结构光纤最令人称奇的一项成就就是实现了光在空气纤芯中的长距离传输。这最早来自于Philip Russell、Jonathan Knight和Tim Birks三位教授共同发明的“光子禁带”空芯光纤。最近几年，随着对“反谐振”导光机理的深入研究，空芯光纤的传输损耗达到了0.28dB/km的记录水平。我们组在“反谐振”空芯光纤实验和理论研究方面，是国际上最早的一批开拓者之一。我们将继续聚焦这一方向，推动“反谐振”空芯光纤各项性能指标全面超越石英玻璃光纤。

另外，在实芯光纤方面，微结构光纤的方法也带来了前所未有的无截止单模、灵活调节色散、大模场、强非线性、强双折射率等一系列特性。这些都得益于微结构光纤制作方法的灵活性和多样性，并在光纤激光和光纤传感领域带来了极丰富的应用。我们组拥有先进的光纤制作设备、丰富的拉制经验、和深厚理论分析能力，我们将瞄准光纤应用的实际需求，开展相关领域的研究工作。