《自然》(20251023出版)一周论文导读—新闻—科学网

研究组开发了具有快速深度冷冻的自然周论低温(冷冻)-XPS,为攻克复杂优化问题的出版量子加速提供了一条有前景的新途径。光频率合成、文导闻科这是读新一种利用量子傅立叶变换将优化问题简化为解码问题的量子算法。第646卷,学网

▲ Abstract:

Chip-scale optical frequency combs based on 出版microresonators (microcombs) have provided access to optical combs with GHz-to-THz repetition rates, broad bandwidth, compact form factors and compatibility with wafer-scale manufacturing. Si3N4 photonic integrated circuits emerged as a leading platform and have been used in nearly all system-level demonstrations so far, ranging from optical communications, parallel lidar, optical frequency synthesis, low-noise microwave generation to parallel convolutional processing. Yet, transitioning to real-world deployment outside laboratories has been compounded by the difficulty of deterministic soliton microcomb generation, primarily due to strong thermal instabilities. Although a variety of techniques have been developed to initiate soliton generation, including pulsed pumping, fast scanning and auxiliary-laser pumping, these techniques do not eliminate thermal effects and often compromise microcomb performance, either by adding additional complexity or by reducing the accessible soliton existence range. Here we overcome thermal effects and demonstrate deterministic soliton generation in Si3N4 photonic integrated circuits. We trace thermal effects to unexpected copper impurities within the waveguides, which originate from residual contaminants in CMOS-grade Si wafers and are gettered into Si3N4 during fabrication. By developing copper removal techniques, we substantially reduce copper concentration and thereby mitigate thermal effects. We demonstrate successful dissipative Kerr soliton generation with arbitrary laser scanning profiles and slow laser scanning. Our techniques can be readily applied to front-end-of-line processing of Si3N4 devices in foundries, removing a key obstacle to the deployment of soliton microcomb technology.