基于光子芯片的亚100飞秒光频梳产生
Photonic-chip-based generation of sub-100-femtosecond optical frequency combs
AI总结：
该研究结合TFLN电光调制器与AlGaAsOI纳米波导基非线性光学环形镜，在光子芯片上实现了55飞秒亚100飞秒光脉冲及10dB带宽超90nm的平顶光频梳，为小型化高稳定光频梳源提供新方案。
AI中文摘要：
亚100飞秒光脉冲及光频梳源已在从超快光学到光频率标准与测量等众多应用领域引发变革。迄今为止，实用系统中产生此类脉冲的主流技术依赖台式锁模激光器，该技术固有地存在系统复杂度高、长期可靠性有限、环境敏感性强的问题。与此同时，在光子集成技术进步的推动下，芯片级方法已致力于实现小型化脉冲源。然而，同时实现亚100飞秒脉宽、理想脉冲形状以及宽带平顶频谱仍是重大挑战。在此，我们通过结合两项关键光子芯片技术解决这些挑战：用于皮秒种子脉冲产生的TFLN电光（EO）调制器，以及基于AlGaAsOI纳米波导的高非线性光学环形镜（NOLM），用于高效的时域脉冲清洁与频谱展宽。在理论模拟与实验中，我们表明，对于中心波长约1550nm的输入种子脉冲，环路长度为1cm的单级AlGaAs NOLM可产生平顶、近十倍频谱展宽、十倍以上脉宽压缩效果，且脉冲 pedestal（基底）抑制超过10dB。利用初始重复频率为10-20GHz的皮秒级EO梳脉冲，我们展示了基于光子芯片的脉冲，其前所未有的脉宽达55飞秒，且10dB光带宽超过90nm的平顶梳频谱。我们的结果凸显了光子芯片技术在实现高重复频率、小型化亚100飞秒光脉冲发生器方面的巨大潜力，这类发生器有望具备优异的稳定性与可操作性。所展示的基于光子芯片的亚100飞秒光频梳源，可能为科学研究与实际应用建立新范式。
英文摘要：
Sub-100-fs optical pulses and frequency comb sources have been revolutionizing a wide range of applications, from ultrafast optical science to optical frequency standard and measurement. To date, the leading techniques for generating such pulses in practical systems rely on tabletop mode-locked lasers, which inherently suffer from high system complexity, limited long-term reliability, and pronounced environmental sensitivity. Meanwhile, driven by advances in photonic integration, chip-scale approaches have sought to realize miniaturized pulse sources. However, simultaneously achieving sub-100-fs duration, ideal pulse shape, and a broadband flat-topped spectrum remains a significant challenge. Here, we address these challenges by combining two key photonic chip technologies: TFLN EO modulators for picosecond seed pulse generation, and highly nonlinear optical loop mirrors (NOLM) based on AlGaAsOI nanowaveguides for efficient temporal pulse cleaning and spectral broadening. In theoretical simulation and experiment, we show that for an input seed pulse centred at ~1550nm, a single-stage AlGaAs NOLM with a loop length of 1cm can produce flat-topped, nearly tenfold spectral broadening and over tenfold compression of pulse width, and more than 10dB suppression of pulse pedestals. Using initial EO comb pulses with ps-level durations at repetition rates of 10-20GHz, we demonstrate photonic-chip-enabled pulses with an unprecedented duration of 55fs and a flat-topped comb spectrum whose 10dB optical bandwidth exceeds 90nm. Our results highlight the remarkable potential of photonic chip technologies to realize high-repetition-rate, miniaturized sub-100-fs optical pulse generators with the prospect of superior stability and operability. The demonstrated photonic-chip-based sub-100-fs optical frequency comb sources may establish a new paradigm for both scientific research and practical applications.
