To ensure the frequency accuracy of a heterodyne laser source in the ambient temperature range of -20°C to 40°C, a dual-longitudinal-mode thermally stabilized He–Ne laser based on non-equilibrium power locking was designed. The ambient adaptive preheating temperature setting scheme ensured the laser could operate normally in the range of -20°C to 40°C. The non-equilibrium power-locked frequency stabilization scheme compensated for the frequency drift caused by different stabilization temperatures. The experimental results indicated that the frequency accuracy of the laser designed in this study could reach 5.2 × 10^-9 in the range of -20°C to 40°C.

The 975 nm multimode diode lasers with high-order surface Bragg diffraction gratings have been simulated and calculated using the 2D finite difference time domain (FDTD) algorithm and the scattering matrix method (SMM). The periods and etch depth of the grating parameters have been optimized. A board area laser diode (BA-LD) with high-order diffraction gratings has been designed and fabricated. At output powers up to 10.5 W, the measured spectral width of full width at half maximum (FWHM) is less than 0.5 nm. The results demonstrate that the designed high-order surface gratings can effectively narrow the spectral width of multimode semiconductor lasers at high output power.

随着电磁环境的日益复杂，电子设备面临的电磁威胁愈加严峻。光电系统作为高灵敏集成化电子设备，强电磁脉冲能量耦合进入系统内部，影响防护能力本就薄弱的光电系统的正常运行。为明晰典型光电系统强电磁耦合过程，通过仿真分析不同强电磁辐照条件下筒型、侧窗型和多窗口型三种典型光电系统的强电磁耦合情况，提取了光电系统强电磁耦合特征及其制约因素，验证了光电系统进行强电磁防护加固的必要性和紧迫性。为解决光电系统强电磁防护能力薄弱的问题，通过仿真分析，验证了透明电磁防护窗口的强电磁加固效能；开展了基于支撑台阶与导电侧壁的电磁缝隙防护加固方法研究，分析了透明防护窗口缝隙耦合泄露的关键安装结构参数，提出了一种非电接触式装配缝隙强电磁防护加固方法。经测试，当缝隙防护结构长度为6 mm时，在0.2～4 GHz频率范围光电系统平均强电磁防护效能提升4.51 dB。研究结果为光电系统强电磁防护能力提升提供了理论指导和具体解决方案。

电源变换系统中功率器件如MOSFET和IGBT开关管的高速切换将产生高幅值和宽频段的电磁干扰，是电动车辆最为常见也无法避免的电磁干扰源。同时，互连线缆是机电设备传递信号和能量的载体，是实现设备功能不可或缺的组成部分，线缆的天线效应使其成为设备产生电磁干扰的主要途径，是系统电磁兼容问题的主要根源之一。为了分析高压电源变换系统对低压控制系统的电磁耦合，以某典型地面装备电源变换系统IGBT开关管产生的脉冲宽度调制波（PWM波）作为电磁干扰源，以实装线缆作为分析对象，构建高低压线缆串扰模型，仿真分析不同线缆对地距离、线缆间距条件下单线、屏蔽线、双绞线等多类低压线缆的近端串扰电压，得出低压线缆的抗干扰性，为系统线缆的布线提供指导。

随着战场环境日益复杂，尤其是高对抗环境下，对现有各类装备均产生了极大威胁。设计了一款C波段雷达接收机保护器，采用充气微波开关管+波导同轴转换的结构设计，创新性地提出将固态限幅器芯片融合在波导同轴转换内部，限幅芯片采用级联的形式，提高了微带限幅器的承受功率。实现接收机保护器耐受功率10 MW以上，响应时间5 ns以内，不仅可用于雷达发射期间接收机防护，还可应对外部电磁干扰、高功率微波攻击。

针对高功率微波波形参数对限幅器温度分布特性的影响，基于双级PIN限幅器的场路协同仿真模型对微波脉冲幅值、频率对温度分布的影响展开了仿真研究。结果表明：微波脉冲幅值、频率的提升会使双级PIN限幅器中PIN二极管的高温区域分布向P区拓展、高温区域分布范围扩大；相对而言，微波脉冲幅值对温度分布的影响更为显著，频率对温度分布的影响相对较小。

光子带隙光纤有着独特的结构形式、传输介质和导光机制，这使其具有传统光纤无法比拟的优点，是未来光纤陀螺的理想选择。但光子带隙光纤粗糙的纤芯内壁导致其产生强烈的背向散射次波，会使光子带隙光纤陀螺产生额外的非互易误差。为了定量分析光子带隙光纤背向散射次波强度大小，论文基于电偶极子辐射理论建立了一种简单的光子带隙光纤背向散射次波理论模型。通过聚焦离子束微纳加工法和原子力显微镜测量得到了准确的纤芯内壁表面形貌功率谱密度，进而计算得到HC-1550-02型光子带隙光纤背向散射系数理论值为2.61×10^-9/mm。通过光频域背向反射散射仪得到HC-1550-02型光子带隙光纤背向散射系数测量值为~1.82×10^-9/mm，初步验证了背向散射次波模型的正确性，为背向散射次波抑制技术研究奠定了基础。

A low-numerical-aperture (NA) concept enables large-mode-area fiber with better single-mode operation ability, which is beneficial for transverse mode instability and nonlinear effects suppression. In this contribution, we reported a high-power fiber amplifier based on a piece of self-developed large-mode-area low-NA fiber with a core NA of 0.049 and a core/inner cladding diameter of 25/400 µm. The influence of the pump wavelength and fiber length on the power scaling potential of the fiber amplifier is systematically investigated. As a result, an output of 4.80 kW and a beam quality factor of ∼1.33 were finally obtained, which is the highest output power ever reported in a fiber amplifier exploiting the low-NA fiber. The results reveal that low-NA fibers have superiority in power scaling and beam quality maintenance at high power levels.

The 1.4–1.8 µm eye-safe lasers have been widely used in the fields of laser medicine and laser detection and ranging. The diamond Raman lasers are capable of delivering excellent characteristics, such as good beam quality concomitantly with high output power. The intra-cavity diamond Raman lasers have the advantages of compactness and low Raman thresholds compared to the external-cavity Raman lasers. However, to date, the intra-cavity diamond cascaded Raman lasers in the spectral region of the eye-safe laser have an output power of only a few hundred milliwatts. A 1485 nm Nd:YVO₄/diamond intra-cavity cascaded Raman laser is reported in this paper. The mode matching and stability of the cavity were optimally designed by a V-shaped folded cavity, which yielded an average output power of up to 2.2 W at a pulse repetition frequency of 50 kHz with a diode to second-Stokes conversion efficiency of 8.1%. Meanwhile, the pulse width of the second-Stokes laser was drastically reduced from 60 ns of the fundamental laser to 1.1 ns, which resulted in a high peak power of 40 kW. The device also exhibited single longitudinal mode with a narrow spectral width of < 0.02 nm.