2026-10-13T01:55:20Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34046823 2026-10-01T16:00:46Z category_37476 portal_1023 item_type_12 month_year_10_2026

A Robust Hertz-Linewidth Quantum-Dot Coherent Swept Source with Adaptive Self-Linearization Wei Chen (23863) Anyao Zhu (21077231) Yueyang Zhang (7878479) Cunyu Shi (22408216) Tao Shu (710427) Taijie Li (519116) Gaopeng Wang (4449814) Zhile Wu (17261929) Liang Tang (48583) Ying Yu (7066) Chenlei Li (15414318) Daoxin Dai (1715983) Physics (arXiv) physics.optics (arXiv) Frequency-modulated continuous-wave (FMCW) techniques underpin both coherent optical ranging and microwave radar, creating a common demand for highly coherent and highly linear frequency-chirped sources across the optical and microwave domains. Conventional semiconductor lasers, however, are fundamentally constrained by trade-offs among linewidth, linear tunability, and operational robustness. Here, we present a robust self-linearized quantum-dot (QD) coherent swept-source architecture through the co-design of source physics and system control. The chaos-free characteristics of QD lasers enable stable low-quality-factor external-cavity locking, yielding a Lorentzian linewidth of 12.6 Hz. Unlike self-injection-locked lasers, broadband external optical feedback allows the laser to maintain high optical coherence and stable operation over a wide current-tuning range, thereby enabling robust turnkey operation together with a chirp bandwidth of 23.2 GHz. Furthermore, a statistically gated real-time iterative learning control (ILC) strategy reduces the chirp nonlinearity $(1-R^2)$ to as low as $8.96\times10^{-8}$, while maintaining excellent environmental stability under laser-temperature variations. To demonstrate practicality, we demonstrate isolator-free coherent LiDAR and photonic generation of frequency-agile, linearly chirped microwave waveforms, establishing a common FMCW source platform for optical ranging and radar waveform synthesis. To the best of our knowledge, we demonstrate for the first time a QD-based coherent swept source that simultaneously combines hertz-level linewidth and ultrahigh chirp linearity, which we envision as a unified source platform for FMCW signal generation and coherent sensing across the optical and microwave domains. 2026-09-29T00:00:00Z Text Preprint 10.48550/arXiv.2609.36666 https://figshare.com/articles/preprint/A_Robust_Hertz-Linewidth_Quantum-Dot_Coherent_Swept_Source_with_Adaptive_Self-Linearization/34046823 CC0