提出并实验研究了一种基于铌酸锂薄膜光波导的电光调谐的光栅辅助定向耦合器。该耦合器由单模与双模脊形波导及制作于双模波导侧壁的长周期光栅构成。长周期光栅的引入补偿了单模与双模波导中基模的相位失配，可在共振波长实现两波导中基模的高效耦合。进一步地，在双模脊形波导两侧制作调谐电极实现了高速、低驱动电压的电光调谐功能。优化了器件的制作工艺，并采用单次干法刻蚀将耦合器的光栅与波导同步制作于X切铌酸锂薄膜上。测试结果表明所制作的器件在1 595.3 nm波长处实现了14.8 dB的隔离度，其电光调谐效率为0.38 nm/V（1 595.3 nm~1 599.0 nm），热光调谐效率为0.14 nm/℃（25 ℃~50 ℃）。该器件可用于实现可调谐滤波、滤模、电光调制及高灵敏度温度传感等功能。

In this work, a hybrid integrated optical transmitter module was designed and fabricated. A proton-exchanged Mach–Zehnder lithium niobate (LiNbO₃) modulator chip was chosen to enhance the output extinction ratio. A fiber was used to adjust the rotation of the polarization direction caused by the optical isolator. The whole optical path structure, including the laser chip, lens, fiber, and modulator chip, was simulated to achieve high optical output efficiency. After a series of process improvements, a module with an output extinction ratio of 34 dB and a bandwidth of 20.5 GHz (from 2 GHz) was obtained. The optical output efficiency of the whole module reached approximately 21%. The link performance of the module was also measured.

We demonstrated a 202 W Tm:YLF slab laser using a reflecting volume Bragg grating (VBG) as an output coupler at room temperature. Two kinds of active heat dissipation methods were used for the VBG to suppress the shift of wavelength caused by its increasing temperature. The maximum continuous wave (CW) output power of 202 W using the microchannel cooling was obtained under the total incident pump power of 553 W, the corresponding slope efficiency and optical-to-optical conversion efficiency were 39.7% and 36.5%, respectively. The central wavelength was 1908.5 nm with the linewidth (full width at half maximum) of 0.57 nm. Meanwhile, with the laser output increasing from 30 to 202 W, the total shift was about 1.0 nm, and the wavelength was limited to two water absorption lines near 1908 nm. The beam quality factors M² were measured to be 2.3 and 4.0 in x and y directions at 202 W.

Commercial white LEDs (WLEDs) are generally limited in modulation bandwidth due to a slow Stokes process, long lifetime of phosphors, and the quantum-confined Stark effect. Here we report what we believe is a novel plasmonic WLED by infiltrating a nanohole LED (H-LED) with quantum dots (QDs) and Ag nanoparticles (NPs) together (M-LED). This decreased distance between quantum wells and QDs would open an extra non-radiative energy transfer channel and thus enhance Stokes transfer efficiency. The presence of Ag NPs enhances the spontaneous emission rate significantly. Compared to an H-LED filled with QDs (QD-LED), the optimized M-LED demonstrates a maximum color rendering index of 91.2, a 43% increase in optical power at 60 mA, and a lowered correlated color temperature. Simultaneously, the M-LED exhibits a data rate of 2.21 Gb/s at low current density of 96A/cm2 (60 mA), which is 77% higher than that of a QD-LED. This is mainly due to the higher optical power and modulation bandwidth of the M-LED under the influence of plasmon, resulting in a higher data rate and higher signal-to-noise ratio under the forward error correction. We believe the approach reported in this work should contribute to a WLED light source with increased modulation bandwidth for a higher speed visible light communication application.

2 μm、中波红外3~5 μm及长波红外8~12 μm波段的激光处于大气传输窗口，在激光医疗、环境监测、激光雷达、化学遥感和红外对抗等领域有着非常广阔的应用前景。基于非线性频率转换技术，采用非线性光学晶体在实现中长波红外固体激光输出方面具有结构简单、宽调谐和高功率等技术优势。尤其是使用2 μm单掺Ho固体激光器泵浦ZnGeP₂晶体，在3~5 μm和8~10 μm中长波红外输出中性能优异。在平均输出功率方面，目前可达到102 W@3~5 μm、12.6 W@8.2 μm以及3.5 W@9.8 μm的输出水平，光束质量M²均小于3，其中中波的光光转换效率可达60%。文中针对2 μm单掺Ho固体激光器及ZnGeP₂晶体在中长波输出方面进行了总结。

To achieve high quality lighting and visible light communication (VLC) simultaneously, GaN based white light emitting diodes (WLEDs) oriented for lighting in VLC has attracted great interest. However, the overall bandwidth of conventional phosphor converted WLEDs is limited by the long lifetime of phosphor, the slow Stokes transfer process, the resistance-capacitance (RC) time delay, and the quantum-confined Stark effect (QCSE). Here by adopting a self-assembled InGaN quantum dots (QDs) structure, we have fabricated phosphor-free single chip WLEDs with tunable correlated color temperature (CCT, from 1600 K to 6000 K), a broadband spectrum, a moderate color rendering index (CRI) of 75, and a significantly improved modulation bandwidth (maximum of 150 MHz) at a low current density of 72A/cm2. The broadband spectrum and high modulation bandwidth are ascribed to the capture of carriers by different localized states of InGaN QDs with alleviative QCSE as compared to the traditional InGaN/GaN quantum well (QW) structures. We believe the approach reported in this work will find its potential application in GaN WLEDs and advance the development of semiconductor lighting-communication integration.

In this study, we propose an effective method for the fabrication of annulus micro-/nanostructures by a femtosecond laser doughnut beam. Compared with the traditional Bessel annulus beam shaping system, this method greatly compresses the light propagation path. It is theoretically and experimentally demonstrated that the obtained axial section of the peak envelope in the processing area is two waists of the isosceles triangle. By moving the relative position of the sample, annulus microstructures with different diameters on copper sheet could be fabricated. In addition, laser induced periodic surface structures with controllable direction are fabricated by this optical system.