Fiber-based quantum entanglement technologies

量子纠缠令科学家们着迷。光纤是一项工程奇迹。两者的结合将带来一场21世纪尚未见证的技术变革，如果说过去预示着未来的话。在激光发明后的60年里，它已经从实验室的好奇心变成了日常生活的必需品。事实上，如果没有激光，互联网和社交媒体是不可能存在的。如果没有光纤，它们也不可能实现。正是激光和光纤这两者的结合，创造了电信业的革命。类似地，在不久的将来，纠缠光子可能会扮演与激光同样重要的角色。两个纠缠粒子之间的“奇怪”关联，曾被爱因斯坦描述为“幽灵般的远距离作用”，有可能成为计算、通信、计量等领域极其强大的资源。例如，基于纠缠的量子密码学利用发送到两个远程方的光子的相关性，并允许它们共享一组通用的随机密码学密钥。它保证了密钥的安全性，因为任何窃听尝试都会导致可检测到的相关性恶化。光子的相关性也可以用来在计量中获得更高的精度。

Quantum entanglement is a fascination of scientists. Optical fibre is a marvel of engineering. The marriage of the two will create a technological transformation the 21st century has yet to witness, if the past is any indication of the future. In the 60 years after the invention of laser, it has transformed from a laboratory curiosity to a necessity in everyday life. Indeed, the Internet and social media would not have been possible without lasers. Nor would they be possible without optical fibre. It was the marriage of the two, lasers and optical fibre, that created the revolution in telecommunications. Analogously, entangled photons will likely play an equally important role as lasers do in not too distant future. The “weird” correlation between two entangled particles, once described by Einstein as “spooky action at a distance,” has the potential to be an extremely powerful resource for computing, communication, metrology, and beyond. Entanglement-based quantum cryptography, for example, utilizes the correlation of the photons sent to two remote parties and allows them to share a common set of random cryptographic keys. It guarantees the security of the keys since any eavesdropping attempt would result in a detectable deterioration of correlation. The correlation of the photons can also be used to achieve higher accuracy in metrology. To best utilize entangled photons as a technological resource, we propose here to use fibre-optics technology as a platform to create and manipulate quantum entanglement, and to demonstrate its practical applications. Built on our unique expertise of generating entangled photons in a specialty fibre the periodically poled silica fibre, and the successful commercialization of the fibre-based entanglement source, we propose to develop several practical technologies using quantum entanglement. More specifically, we propose to develop more sophisticated quantum entanglement sources and better control over their physical properties, and then we will demonstrate how the variety of quantum entanglement these sources offer can be utilized to produce practical technologies in quantum cryptography and quantum metrology. Quantum technology will play an important role in the 21st century. By combining quantum entanglement with practical fiber-optic technologies, this proposal aims to take an important step forward in the development of quantum technology for practical applications.