创新背景

人类在线发布的数据呈指数级增长，光纤容量终将消耗殆尽一直是科学家担心的问题。虽然在某些地区网速连接还是很慢，但“骨干互联网”仍有可能达到某个传输速度的极限。美国加州大学的一个研究团队在2015年创建了一种“频率梳”装置，通过光纤电缆传播破译信息的距离超过1.2万公里，且无需生成新信号，能够预测并解决光纤传播信息过程中的信号失真问题，不需依赖信号增强装置便可直接传输比通常情况强20倍的信号。

光学频率梳是一种特殊的超短脉冲光源，具有稳定的重复频率。它是在频谱上由一系列均匀间隔且具有相干稳定相位关系的频率分量组成的光谱，有数百根间隔精确相等并且相干的激光线梳齿，可以⽤来测量极其精确的时间间隔，在光原⼦钟、量⼦通信、精密测量上应⽤颇多。

创新过程

日常生活中围绕着我们的光会产生混乱频率，而光孤子频率梳的特习惯导致其专用光源的每个光频率都震荡一致，产生时间间隔一直的鼓励脉冲，但目前频率梳的量子光学性质尚且无法确定。斯坦福大学的研究人员是最早研究频率梳量子光学性质的人之一，创建之初的光孤子频率梳表现出粒子纠缠的现象，可以在芯片上产生有趣的量子光，巩固增加了科学家对量子物理学的理解。

小型化频率梳在芯片上产生的量子光为相关领域的探索开辟了道路，研究可以使用频率梳和光子集成电路进行大规模实验探究。研究人员为了节省成本和能源，将系统的所有部分集成到单个设备中设计微芯片。使用斯坦福纳米共享设施和纳米制造设施设计制造的碳化硅的微观环泵浦激光，激光在环上行进时增强强度进而产生孤子。在芯片上生成的微梳子可以在齿间实现宽间距，促使研究能够查看梳子的精细化细节。之后的研究使用到能够检测光的单个颗粒的设备和用几个孤子填充的微环，从而形成了孤子晶体。

孤子晶体可以让人看到齿间存在更小的光脉冲，这是研究用来推断纠缠结构的工具。如果将探测器停在那里，可以不被构成梳齿的相干光影响，观察到奇妙的量子行为。研究人员尝试确认一个称为线性化模型的理论模型，用于描述复杂量子系统。当研究结果和模型进行对比时，研究人员发现实验与理论高度吻合，因此，在还没有直接测量证明微梳具有量子纠缠的时候，研究已经证明它的性能与暗示纠缠的理论相匹配。

孤子一旦产生就被预测为高度纠缠，研究将继续从量子角度探究光孤子频率梳的性质，尽力挖掘其潜力。

创新关键点

利用孤子微型频率梳研究频率梳的量子特性，进一步探索量子特性和量子纠缠的存在。

创新价值

开发频率梳的微型版本有助于提高数据传输的速度，如为GPS系统提供更精确的信息。

Explore the quantum properties of optical frequency combs through soliton microcombs

The light surrounding us in daily life produces chaotic frequencies, and the special habit of the soliton frequency comb causes each light frequency of its dedicated light source to oscillate all the time, generating encouraging pulses at a time interval, but the quantum optical properties of the frequency comb are still uncertain. Researchers at Stanford University were among the first to study the quantum optical properties of frequency combs, and the light soliton frequency combs that were created at the beginning showed the phenomenon of particle entanglement, which could produce interesting quantum light on the chip, consolidating and increasing scientists' understanding of quantum physics.

The quantum light generated on the chip by miniaturized frequency combs opens the way for exploration in related fields, and research can use frequency combs and photonic integrated circuits for large-scale experimental exploration. To save costs and energy, the researchers integrated all parts of the system into a single device to design microchips. Microscopic ring-pumped lasers of silicon carbide designed and manufactured using stanford nano-sharing facilities and nanofabrication facilities increase strength as the laser travels on the ring to produce solitons. The micro-combs generated on the chip can achieve wide spacing between teeth, prompting the study to be able to see the fine details of the combs. Subsequent studies used equipment capable of detecting individual particles of light and microcycles filled with several solitons, resulting in soliton crystals.

Soliton crystals allow smaller pulses of light between teeth to be seen, a tool used to study the structure of entanglement. If the detector is parked there, it can observe wonderful quantum behavior without being affected by the coherent light that makes up the comb teeth. The researchers attempted to confirm a theoretical model called a linearized model for describing complex quantum systems. When the results of the study were compared to the model, the researchers found that the experiment was highly consistent with the theory, so that at a time when there had been no direct measurements to prove that the microcomb had quantum entanglement, the study had shown that its performance matched the theory of suggestive entanglement.

As soon as the soliton is generated, it is predicted to be highly entangled, and research will continue to explore the properties of the light soliton frequency comb from a quantum perspective, trying to tap its potential.