A polarization-insensitive mode-order converting power splitter using a pixelated region is presented and investigated in this paper. As TE₀ and TM₀ modes are injected into the input port, they are converted into TE₁ and TM₁ modes, which evenly come out from the two output ports. The finite-difference time-domain method and direct-binary-search optimization algorithm are utilized to optimize structural parameters of the pixelated region to attain small insertion loss, low crosstalk, wide bandwidth, excellent power uniformity, polarization-insensitive property, and compact size. Experimental results reveal that the insertion loss, crosstalk, and power uniformity of the fabricated device at 1550 nm are 0.57, -19.67, and 0.094 dB in the case of TE polarization, while in the TM polarization, the relevant insertion loss, crosstalk, and power uniformity are 0.57, -19.40, and 0.11 dB. Within a wavelength range from 1520 to 1600 nm, for the fabricated device working at TE polarization, the insertion loss, crosstalk, and power uniformity are lower than 1.39, -17.64, and 0.14 dB. In the case of TM polarization, we achieved an insertion loss, crosstalk, and power uniformity less than 1.23, -17.62, and 0.14 dB.

A flexible-grid 1×(2×3) mode- and wavelength-selective switch which comprises counter-tapered couplers and silicon microring resonators has been proposed, optimized, and demonstrated experimentally in this work. By carefully thermally tuning phase shifters and silicon microring resonators, mode and wavelength signals can be independently and flexibly conveyed to any one of the output ports, and different bandwidths can be generated as desired. The particle swarm optimization algorithm and finite difference time-domain method are employed to optimize structural parameters of the two-mode (de)multiplexer and crossing waveguide. The bandwidth-tunable wavelength-selective optical router composed of 12 microring resonators is studied by taking advantage of the transfer matrix method. Measurement results show that, for the fabricated module, cross talk less than -10.18dB, an extinction ratio larger than 17.41 dB, an in-band ripple lower than 0.79 dB, and a 3-dB bandwidth changing from 0.38 to 1.05 nm are obtained, as the wavelength-channel spacing is 0.40 nm. The corresponding response time is measured to be 13.64 µs.

为了丰富当前可用红外材料的种类，满足新一代红外成像光学系统的轻薄化设计需求，充分利用硫系玻璃组分可调和色散参数可选两大特殊优势，开发了新型硫系玻璃材料，并且在同一系统指标要求下，分别对基于传统红外材料和基于新型硫系玻璃设计的红外光学系统进行了性能对比。基于高折射率硫系玻璃的中波双视场红外光学系统，有效实现了去锗化设计，与基于传统红外材料的红外光学系统相比较，光学系统质量减轻了35%，长度减少了15%，透过率提高了10%。基于叠层梯度折射率(gradient refractive index, GRIN)硫系玻璃的共光路、共焦面双波段红外光学系统，在非制冷型中/短波红外成像光学系统中首次实现了胶合透镜的设计，与基于传统红外材料的双波段红外光学系统相比较，光学系统质量减轻了40%，长度减少了30%，透过率提高了15%；在制冷型中/长波红外光学系统中，具有不同折射率差值Δn的GRIN硫系玻璃展现出卓越的色差校正能力，与基于传统红外材料的双波段红外光学系统相比较，光学系统质量减轻了20%，长度减少了20%，透过率提高了18%。设计结果表明，新型硫系玻璃的出现，是对现有红外材料的有益补充，为新一代红外成像光学系统提供了更为丰富的材料选择和更多的设计自由度，是实现轻薄化透射式红外光学系统的重要技术途径。

基于空分复用技术的多芯光纤通信核心指标之一是信道串扰，该问题的存在极大地影响着传输距离及信号质量，尤其是在宽带光纤放大系统中。本文重点讨论了弱耦合19芯光纤的串扰问题，同时提出了一种利于多组分碲酸盐玻璃挤压制备的沟槽辅助型19芯光纤，并采用耦合功率理论和有限元法对模型进行了相关性能的数值仿真，系统研究了沟槽尺寸、折射率分布及相关光纤参数对芯间串扰的影响。仿真结果表明，优化设计后的光纤在1 550 nm处拥有-156 dB/100 m的低串扰值，可以满足大容量光纤通信用宽带光放大器的应用需求。

采用高温浮粉熔融法制备了组分为60TeO₂?10GeO₂?20BaF₂?9Y₂O₃?1Er₂O₃的Er³⁺掺杂氟碲酸盐玻璃微球，并对其品质因子（Q）、近红外激光特性以及温度传感进行了细致研究。结果发现微球腔的Q值可高达 ~10⁶。在980 nm激光泵浦下，在直径为44.58 μm的微球中实现了阈值为54 μW、光学转换效率为0.050%的 1 607 nm激光输出。通过研究不同直径对微球腔激光性能的影响规律，可知随着微球腔直径的减小，激光阈值逐渐降低，光学转换效率逐渐提高，这主要归因于较小的微球腔具有更高的能量密度和更强的光与物质相互作用。此外，研究了微球腔的温度传感特性，其灵敏度为14 pm/℃。以上实验结果表明，所制备的Er³⁺掺杂氟碲酸盐玻璃微球腔在低阈值激光器和高灵敏度温度传感器领域具有潜在的应用。