We proposed a compact and tunable multimode interferometer (MMI) based on an asymmetric wavy fiber (AMWF), which has axial offset, off-center taper waist, and micro-length. The fabrication process only contains non-axis pulling processes of single-mode fiber on two close positions. Theoretical qualitative analyses and experiments verify the tunable multimode propagation of the AMWF. Experimental results show a nonlinear wavelength response with increasing axis displacement from 0 to 120 μm. In the range of 0—10 μm, the sensitivity reaches the highest value of -1.33 nm/μm. Owing to its cost-effective, high-compact and tunable multimode propagation properties, the AMWF provides a promising platform for micro-nano photonic devices and optical sensing applications.

Consumption of fossil fuel has led to serious environmental pollution, and an urgent demand for solar energy. Perovskite solar cell (PSC) is a device that converts solar energy into electricity. It is cost effective and power efficient, which has attracted much attention. However, PSC shows low absorptivity due to the limited thickness of the active layer. In this paper, a bilateral L-shaped metal grating structure is introduced into the PSC to enhance the absorptivity of the active layer by the surface plasmon effect between the metaling grating and the TiO2. With the deflection angle of the inner angle connection line of the metal grating is 45°, the inner angle distance is 100 nm, and the structural period is 250 nm, the absorptivity of the active layer of the PSC is 86.5% at 715 nm, which is 28.6% higher than the conventional solar cell at the same wavelength. Such results provide an effective way to improve the absorption of PSCs.

利用熔接机电弧放电和氢气火焰加热相结合的方法,在光纤直径骤减的锥区中心位置制得非绝热型微光纤。该光纤结构具有较强的倏逝场,可以大幅增强光与物质的相互作用。将其与磁流体进行集成,基于磁流体的磁场可调谐折射率变化特性,能够实现对外界弱磁场的快速测量。研究结果表明,在0~150 Oe的磁场强度范围内,灵敏度可达193.28 pm/Oe,探测极限约为0.187 Oe,并且其灵敏度随着干涉峰波长的增大而增大。该传感器具有体积小、成本低、制作方法简单等优点,在电磁场检测领域具有良好的应用前景。

报道了一种锁波长914 nm共振抽运的Nd∶YVO4/LBO腔内倍频的绿光激光器,利用锁波长914 nm的半导体激光器作为抽运源,极大地提高了抽运的均匀性和抽运效率,降低了激光器的热效应,从而获得了高光束质量的532 nm激光输出。当抽运功率为18 W,调制频率为130 kHz时,获得了最高输出功率为6.7 W的绿光,入射抽运光的光-光转换效率为37.2%,对应的吸收抽运光的光-光转换效率为60%。

基于液体材料填充的微结构光纤光子器件有效地将功能材料在不同外界物理场作用下的物理效应同光纤自身的微纳结构结合起来，具有可调谐、设计灵活、全光纤结构和易于集成等优点，是未来光纤光子器件发展的重要方向。掌握不同填充材料、填充方法及所制作器件的不同特性、功能和应用对这一领域的研究具有重要的指导意义。综合阐述了近年来基于液体材料填充的微结构光纤光子器件的研究进展，分析和归纳了各种液态功能材料的种类、物理特性及填充方法，系统阐述了基于该种方法实现的光开关及衰减器、滤波器、调制器、色散补偿器等可调谐光纤光子器件及光纤传感器件，最后对该领域未来的发展方向和前景进行了展望，为未来新型光纤光子器件的研制提供必要的依据和参考。

In this paper, the mode coupling mechanism of tilted fiber Bragg gratings (TFBGs) is briefly introduced at first. And a general review on the fabrication, theoretical and experimental research development of TFBGs is presented from a worldwide perspective, followed by an introduction of our current research work on TFBGs at the Institute of Modern Optics, Nankai University (IMONK), including TFBG sensors for single-parameter measurements, temperature cross sensitivity of TFBG sensors, and TFBG-based interrogation technique. Finally, we would make a summary of the related key techniques and a remark on prospects of the research and applications of TFBGs.

基于单个倾斜光纤光栅(TFBG)提出了一种实现双参量曲率和温度同时测量的方法。研究发现,当弯曲方向与光栅栅面成一定角度时，倾斜光纤光栅的纤芯模谐振波长对弯曲不敏感而随外界温度变化线性漂移；低阶包层模谐振峰透射功率随曲率的增加而线性减小且对温度变化不敏感。由此特性提出了用单个倾斜光纤光栅的纤芯模谐振波长和低阶包层模谐振峰透射功率,分别实现对两个参量温度和曲率进行同时独立测量的传感器设计方案，该方法有望解决光纤光栅在测量中存在的温度和弯曲之间的交叉敏感问题。

倾斜光纤光栅的透射谱中有纤芯模和大量的包层模, 它们具有与布拉格光栅相同的温度特性。利用HF酸腐蚀的方法得到具有不同包层直径的倾斜光纤光栅, 研究了其对外界折射率的传感特性。结果表明, 外界环境折射率在1.333～1.4532之间变化时, 同一直径倾斜光纤光栅的高阶包层模的敏感性要比低阶包层模强; 随着包层直径的减小, 包层模的敏感性增强, 且在折射率比较高的环境中有更高的敏感性。因此, 利用倾斜光纤光栅的温度特性不仅可以解决温度交叉敏感问题, 而且通过不同的腐蚀程度能定制所需要的灵敏度, 以实现对环境折射率的高灵敏度测量。该方法可应用于对生物和化学等高灵敏度传感领域的各种溶液进行实时监控。