We study how to optimize the coupling efficiency between silicon nitride and silicon waveguides using an edge coupler with an inverse-tapered structure, specifically targeting broad bandwidth applications. Initially, we hypothesized that mode matching alone would suffice for effective coupling. However, our results indicate that maximizing the coupling efficiency requires the simultaneous optimization of mode coupling and effective refractive-index matching. Theoretical simulations predicted a maximum coupling efficiency of 0.963, while experimental measurements yielded an efficiency of 0.588. We analyzed the wavelength dependence of our coupler, and found that the edge coupler exhibited broader bandwidth properties than a standard multilayer coupler, making it more suitable for applications across a wide wavelength range. These results indicate the potential for integrating such couplers with microresonator frequency comb systems, offering the possibility of a wide range of photonic applications.

Aiming at the problem of high common-mode voltage in active midpoint clamp (ANPC) three-level three-phase four-bridge inverter topology, a common-mode voltage suppression strategy based on carrier reversal is proposed, which can suppress common-mode voltage (CMV) under different operating conditions. The influence factors of CMV and the influence law of carrier change on CMV are analyzed, and the effect of reverse carrier modulation strategy on suppressing CMV is proved. The new modulation strategy proposed in this paper is a further improvement on the traditional reverse carrier modulation strategy. This suppression strategy can effectively reduce the CMV peak and switching times, but does not occupy additional dsp computing resources. Finally, the feasibility and effectiveness of the proposed method are verified on the experimental platform.

For integrated circuit design, optimizing circuit parameters is crucial to achieve wide operating margins and high yields, even in the presence of fluctuations and variations in device characteristics. In this paper, we report the development of a new circuit parameter optimization tool for superconductor integrated circuits, leveraging the latest analog circuit simulator and the center of gravity method. The developed optimization tool, implemented in C++, utilizes a parallel processing algorithm for high-speed optimization. By using only the phase information of the Josephson junction to distinguish the correct behavior of the circuit, this tool can be applied not only to conventional single flux quantum (SFQ) circuits but also to superconductor circuits whose behavior is not based on a 2π phase change. We optimized several SFQ logic gates and compared the margin expansion and optimization time with conventional optimization tools. Our tool achieved an optimization time of less than 2% of that of conventional tools in most cases. This optimization tool facilitates the rapid parameter optimization of any superconductor circuits containing various types of Josephson junctions.

The Agile Earth Observation Satellite Constellations Mission Planning (AEOSCMP) problem seeks to maximize global cumulative reward by optimizing task selection and scheduling across the Earth’s surface while adhering to the intricate resource constraints of individual satellites. This optimization challenge is further complicated by the diverse observation intervals required for different targets and the necessity for coordinated action among multiple satellites, introducing complexities in synchronization, data consistency, and overall mission planning. Deep reinforcement learning (DRL) and target clustering represent two complementary methodologies that synergistically enhance the autonomy and observation efficiency of AEOSCMP. This letter introduces an innovative approach that elegantly unifies these two methodologies - the Integrated Clustering and Planning with Proximal Policy Optimization Algorithm (ICP3O). This sophisticated framework seamlessly preserves the intelligent decision-making capabilities inherent to DRL while delivering substantial improvements in observation efficiency.