We propose a joint look-up-table (LUT)-based nonlinear predistortion and digital resolution enhancement scheme to achieve high-speed and low-cost optical interconnects using low-resolution digital-to-analog converters (DACs). The LUT-based predistortion is employed to mitigate the pattern-dependent effect (PDE) of a semiconductor optical amplifier (SOA), while the digital resolution enhancer (DRE) is utilized to shape the quantization noise, lowering the requirement for the resolution of DAC. We experimentally demonstrate O-band intensity modulation and direct detection (IM/DD) transmission of 124-GBd 4 / 6-level pulse-amplitude modulation ( PAM ) -4 / 6 and 112-GBd PAM-8 signals over a 2-km standard single-mode fiber (SSMF) with 3 / 3.5 / 4-bit DACs. In the case of 40-km SSMF transmission with an SOA-based preamplifier, 124-GBd on-off-keying (OOK)/PAM-3/PAM-4 signals are successfully transmitted with 1.5 / 2 / 3-bit DACs. To the best of our knowledge, we have achieved the highest net data rates of 235.3-Gb / s PAM-4, 289.7-Gb / s PAM-6, and 294.7 Gb / s PAM-8 signals over 2-km SSMF, as well as 117.6-Gb / s OOK, 173.8-Gb / s PAM-3, and -231.8 Gb / s PAM-4 signals over 40-km SSMF, employing low-resolution DACs. The experimental results reveal that the joint LUT-based predistortion and DRE effectively mitigate the PDE and improve the signal-to-quantization noise ratio by shaping the noise. The proposed scheme can provide a powerful solution for low-cost IM/DD optical interconnects beyond 200 Gb / s.

The performance and reliability of ferroelectric thin films at temperatures around a few Kelvin are critical for their application in cryo-electronics. In this work, TiN/Hf_0.5Zr_0.5O₂/TiN capacitors that are free from the wake-up effect are investigated systematically from room temperature (300 K) to cryogenic temperature (30 K). We observe a consistent decrease in permittivity (ε_r) and a progressive increase in coercive electric field (E_c) as temperatures decrease. Our investigation reveals exceptional stability in the double remnant polarization (2P_r) of our ferroelectric thin films across a wide temperature range. Specifically, at 30 K, a 2P_r of 36 μC/cm² under an applied electric field of 3.0 MV/cm is achieved. Moreover, we observed a reduced fatigue effect at 30 K in comparison to 300 K. The stable ferroelectric properties and endurance characteristics demonstrate the feasibility of utilizing HfO₂ based ferroelectric thin films for cryo-electronics applications.

针对兆伏每米（MV/m）强脉冲电场的测量需求，设计并研制了基于集成光学的共路干涉仪（CPI）小体积宽带脉冲电场传感器。基于电光效应及电光调制原理，建立了传感器的幅度和频率响应传递函数，分析了集成光学探头的接收特性，并推导了探头灵敏度和带宽随波导长度的关系。设计了适用于MV/m量级脉冲电场测量的纯光学非金属CPI传感器，提出了利用晶体宽度对测量灵敏度调控的方法，使得设计的半波电场提高了2倍以上。研制的无源探头体积小于20 mm×10 mm×5 mm、理论带宽大于4 GHz、最大测量幅度大于1.2 MV/m。研制的传感器在高空电磁脉冲（HEMP）、雷电电磁脉冲（LEMP）及脉冲功率等领域具有应用前景。

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。

Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied, the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.

Valley topological photonic crystals (TPCs), which are robust against local disorders and structural defects, have attracted great research interest, from theoretical verification to technical applications. However, previous works mostly focused on the robustness of topologically protected edge states and little attention was paid to the importance of the photonic bandgaps (PBGs), which hinders the implementation of various multifrequency functional topological photonic devices. Here, by systematically studying the relationship between the degree of symmetry breaking and the working bandwidth of the edge states, we present spoof surface plasmon polariton valley TPCs with broadband edge states and engineered PBGs, where the operation frequency is easy to adjust. Furthermore, by connecting valley TPCs operating at different frequencies, a broadband multifunctional frequency-dependent topological photonic device with selectively directional light transmission is fabricated and experimentally demonstrated, achieving the functions of wavelength division multiplexing and add–drop multiplexing. We provide an effective and insightful method for building multi-frequency topological photonic devices.

基于光子晶体非线性效应和线性干涉效应设计了全光异或、非和与逻辑门。应用反演定理拆分较复杂逻辑表达式，通过级联组合设计了全光或非门和四输入与门逻辑器件。本文利用时域有限差分法进行仿真模拟计算，对非线性环形腔的耦合特性进行了分析，然后在信号波长为1.47 μm条件下设计了上述逻辑器件，且通过可扩展输入端可设计出更多输入的器件。分析了信号功率对四输入与逻辑器件逻辑功能的影响。结果表明信号光源功率在1.1 W/μm²到3.4 W/μm²之间时，输出端的逻辑对比度均大于10 dB。所设计器件响应时间最短仅1.6 ps，占用面积小，易于扩展与集成，在光处理系统和集成光路中有较大应用前景。