近日，美国斯坦福大学的Amir H. Safavi-Naeini及其研究团队取得一项新进展。经过不懈努力，他们研制出集成调频光参量振荡器。相关研究成果已于2024年3月6日在国际权威学术期刊《自然》上发表。

该研究团队引入了一种以前未知的微梳——一种结合了电光和参数放大的集成器件，从而产生调频光学参数振荡器(FM-OPO)。与其他解决方案相比，它不形成脉冲，但保持操作简单和高效的泵浦功率利用，输出类似于调频激光。研究人员概述了该器件的工作原理，并通过在铌酸锂薄膜上制作完整的光学系统进行了演示。

研究人员测量到泵到梳的内部转换效率超过93%(34%的外耦合)，几乎是平顶的光谱分布，跨越大约200种模式(超过1THz)。与电光梳相比，决定FM-OPO带宽的是腔色散而不是损耗，这使得宽带梳具有更小的射频调制功率。FM-OPO微梳提供稳定的运行动态，高效率和宽带宽，有望用于计量，光谱学，电信，传感和计算的紧凑型精密工具。

据悉，光学频率梳彻底改变了精密测量、计时和分子光谱学。围绕“微梳”已经做出了大量的努力: 将梳生成技术集成到紧凑的光子平台中。目前产生这些微梳的方法包括电光效应或克尔机制。尽管进展迅速，但保持高效率和宽带宽仍然是一项挑战。

附：英文原文

Title: Integrated frequency-modulated optical parametric oscillator

Author: Stokowski, Hubert S., Dean, Devin J., Hwang, Alexander Y., Park, Taewon, Celik, Oguz Tolga, McKenna, Timothy P., Jankowski, Marc, Langrock, Carsten, Ansari, Vahid, Fejer, Martin M., Safavi-Naeini, Amir H.

Issue&Volume: 2024-03-06

Abstract: Optical frequency combs have revolutionized precision measurement, time-keeping and molecular spectroscopy. A substantial effort has developed around ‘microcombs’: integrating comb-generating technologies into compact photonic platforms. Current approaches for generating these microcombs involve either the electro-optic or Kerr mechanisms. Despite rapid progress, maintaining high efficiency and wide bandwidth remains challenging. Here we introduce a previously unknown class of microcomb—an integrated device that combines electro-optics and parametric amplification to yield a frequency-modulated optical parametric oscillator (FM-OPO). In contrast to the other solutions, it does not form pulses but maintains operational simplicity and highly efficient pump power use with an output resembling a frequency-modulated laser. We outline the working principles of our device and demonstrate it by fabricating the complete optical system in thin-film lithium niobate. We measure pump-to-comb internal conversion efficiency exceeding 93% (34% out-coupled) over a nearly flat-top spectral distribution spanning about 200 modes (over 1THz). Compared with an electro-optic comb, the cavity dispersion rather than loss determines the FM-OPO bandwidth, enabling broadband combs with a smaller radio-frequency modulation power. The FM-OPO microcomb offers robust operational dynamics, high efficiency and broad bandwidth, promising compact precision tools for metrology, spectroscopy, telecommunications, sensing and computing.

DOI: 10.1038/s41586-024-07071-2

Source: https://www.nature.com/articles/s41586-024-07071-2