Quantum Communications breakthrough! Are noise-canceling headphones to cue quantum communication, noise, interference cancellation-IT information

Scientists using principles similar to the noise-canceling headphones, making can eliminate stray light output of a single photon of light.

This enlargement effect diagram shows the gallium arsenide (GaAs) chip structures. Pink tapered at the bottom represents the classic laser incident. The blue areas represent Indium Arsenide (InAs), when the classic laser can produce single photons. Above the pink Cone and blue taper respectively and represents a classic shoot laser single-photon through secure communication of a single photon can achieve absolute security.

Quantum communication is a promising future communications technologies. By means of quantum communications, doctors, banks, tax authorities and we can absolutely secure communications without fear of personal data breaches. Even if someone attempts to steal confidential information, we can immediately know.

However, to create quantum networks and quantum communication as a standard means of communication, we still have many problems to overcome, and one of the most important is how to send and receive the quantum data. In this context, researchers at Stanford University have invented a new type of quantum source, it might form the basis of future quantum communication. On the study in nature Photonics team released their study results.

Quantum communication complexity of the physical principles. Current standard laser source is not suitable for confidential communications, because of this laser source emits is "classic" light, we are unable to determine whether their information has been stolen. By contrast, in quantum communication networks using a single photon is a quantum of light. Photons are the smallest units of light, once left to measure, would destroy the message carried by photons. Therefore, efficient quantum light sources has become an important part of quantum communication system.

Jelena Vuckovic was the main author of this article (senior author), she is a Professor of electrical engineering at Stanford University, is studying nano-sized laser source in recent years and the associated quantum technology. She wants to rely on traditional computer signal communication improved optical signal communications, so as to improve your computer′s speed. Her doctoral student Kevin Fischer, who improved the Nano laser source, so that it can efficiently produce single photons for quantum communications.

Vuckovic said: "this research is the key to identifying a single photon, because single-photon intensity than the light produced by light intensity is much weaker. To this end, we found a way to filter out stray light, which greatly improves the device identification capability of Photonic signals. ”

Filter out stray light using the method and noise-canceling headphones work like: noise-canceling headphones contain a sensor that can instantly detect the ambient noise of relatively stable frequencies, such as cars passing on the street sound, the roar of airplane engines, refrigerator compressor noise, then the headset will produce a waveform similar to sound waves, noise to offset. Vuckovic, who is using this idea, eliminating the experiment of "noise". "Laser light source back light cover single photon. Only subtracted from the signal light, can we identify hidden quantum signal, then quantum signal strengthening. "Fischer explained.

Vuckovic team drew in the 1930 of the 20th century, radio technology, with "interference cancellation" method to offset the extra classic. They first studied these stray light waves, then artificially created wave similar but different light phase, two light offset through the precision adjustment, and to eliminate stray light, reveal meaningful single-photon signals.

"This is a significant development, laid the Foundation for the realization of quantum communication. "Vuckovic said. At present, she is leading the team developed a prototype quantum light source, further results will be announced in the future.

量子通信得到突破！是降噪耳机给的启发 - 量子通信,降噪,干涉相消 - IT资讯

科学家利用类似于降噪耳机的原理，制造出了可以消除杂光输出单个光子的光源。

这张放大的效果图中显示了砷化镓（GaAs）芯片的结构。下方的粉红色锥形表示入射的经典激光。中间的蓝色区域表示砷化铟（InAs），当经典激光通过的时候会产生单个光子。上方的粉红色锥形和蓝色锥形分别表示射出的经典激光和单光子，借助单光子便可以实现绝对安全的保密通信。

量子通信是一种对前景光明的未来通信技术。借助量子通信，我们可以和医生、银行、税务部门进行绝对安全的沟通，不必担心私人数据泄露。甚至，一旦有人试图盗取机密信息，我们也可以立即知晓。

然而，要想建立量子网络，并以量子通信为标准通信方式，我们还有很多技术难题需要克服，而其中最关键的一个是如何收发量子数据。在这一方面，斯坦福大学的研究人员发明了一种新型量子光源，它或许能够成为未来量子通信的基础。该研究团队在《自然·光子学》上发布了他们的这项研究成果。

量子通信的物理原理比较复杂。目前的标准激光源不适合用于保密通信，因为这种激光源发出的是“经典”的光，我们无法判断其携带的信息是否已经被窃取。相比之下，量子通信网络中使用的是量子光源发出的单个光子。光子是光的最小单位，一旦有人对其实施测量，就会破坏这个携带信息的光子。因此，高效的量子光源便成为量子通信系统中的重要一环。

Jelena Vuckovic是这篇文章的主要作者（senior author），她是斯坦福大学电气工程专业的教授，近年来正在研究纳米尺寸激光源以及相关的量子技术。她希望将传统计算机中依靠电信号通信的方式改进为光信号通信，从而提高计算机的通信速率。她带领博士生Kevin Fischer等人改进了一种纳米激光源，使其可以高效地产生单光子，用于量子通信。

Vuckovic说：“这项研究的关键在于如何辨认单光子，因为单光子的强度比光源所产生的杂光的强度弱很多。为此，我们找到了一种滤除杂光的方法，从而大大提升了装置识别光子信号的能力。”

滤除杂光所使用的方法与降噪耳机的工作原理类似：降噪耳机中含有一个传感器，可以即时侦测相对稳定的环境噪声的频率，例如马路上汽车驶过的声音、飞机引擎的轰鸣、冰箱压缩机的噪音等，然后耳机中会产生波形相似的声波，将噪音抵消掉。Vuckovic等人正是利用这种思路，消除了实验中的“光噪声”。“激光光源反馈回来的杂光会遮盖住单光子。只有把杂光从信号中扣除，我们才能找出其中隐藏的量子信号，再将量子信号加强。”Fischer解释道。

Vuckovic团队借鉴了20世纪30年代的无线电技术，用“干涉相消”的方法抵消掉了多余的经典光。他们首先研究清楚这些杂光的波形，然后人为制造出波形相似但相位不同的光，通过精密的调节使两种光叠加抵消，于是杂光便得以消除，有意义的单光子信号则显露出来。

“这是一项重大进展，为实现量子通信奠定了基础。”Vuckovic说道。目前，她正带领团队研制原型量子光源，进一步成果将在未来公布。