An optical-frequency synthesizer using integrated photonics
An optical-frequency synthesizer using integrated photonics
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DOI：
10.1038/s41586-018-0065-7
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发表时间：
2018-05-03
期刊：
影响因子：
64.8
通讯作者：
Papp, Scott B.
中科院分区：
文献类型：
--
作者：
Spencer, Daryl T.;Drake, Tara;Papp, Scott B.
光学频率合成器从单个微波频率参考产生频率稳定的光，正在彻底改变超快科学和计量学，但如果要更广泛地使用，则需要降低其尺寸，功率要求和成本。集成光子微芯片可用于高相干应用，如数据传输（1），高度优化的物理传感器（2）和利用量子态（3），以降低成本，提高效率和便携性。在这里，我们描述了一种用于合成光波信号的绝对频率的方法，使用集成光子学来创建相位相干的微波到光链路。我们使用一个异质集成的III-V/硅可调谐激光器，这是由非线性频率梳在单独的硅芯片上制造和芯片外激光器泵浦。我们的光频合成器的激光频率输出可以通过微波时钟编程，在1,550纳米（电信C波段）附近的4太赫兹范围内，分辨率为1赫兹。我们的测量验证了合成器的输出在该区域非常稳定（合成误差为7.7 x 10（-15）或更低）。光频源的任何应用都可以从这里介绍的高精度光学合成中受益。利用围绕先进材料构建的大批量半导体处理可以使这种低成本，低功耗和紧凑的集成光子器件得到广泛应用。
Optical-frequency synthesizers, which generate frequency-stable light from a single microwave-frequency reference, are revolutionizing ultrafast science and metrology, but their size, power requirement and cost need to be reduced if they are to be more widely used. Integrated-photonics microchips can be used in high-coherence applications, such as data transmission(1), highly optimized physical sensors(2) and harnessing quantum states(3), to lower cost and increase efficiency and portability. Here we describe a method for synthesizing the absolute frequency of a lightwave signal, using integrated photonics to create a phase-coherent microwave-to-optical link. We use a heterogeneously integrated III-V/silicon tunable laser, which is guided by nonlinear frequency combs fabricated on separate silicon chips and pumped by off-chip lasers. The laser frequency output of our optical-frequency synthesizer can be programmed by a microwave clock across 4 terahertz near 1,550 nanometres (the telecommunications C-band) with 1 hertz resolution. Our measurements verify that the output of the synthesizer is exceptionally stable across this region (synthesis error of 7.7 x 10(-15) or below). Any application of an optical-frequency source could benefit from the high-precision optical synthesis presented here. Leveraging high-volume semiconductor processing built around advanced materials could allow such low-cost, lowpower and compact integrated-photonics devices to be widely used.