Silicon Photonic Circuits for Quantum Information Processing

我们在使用工作波长接近1.5 µm的绝缘体上硅晶片设计、制造和光学操纵基于平面波导的光子电路方面的丰富经验，将指导开发工作波长约为2.9 µm的类似电路。 这是由硅光子电路最令人兴奋的潜在应用之一，即量子信息处理，特别是最近发现的硅中的光学活性单原子杂质位点，当与我们以前开发的元素结合时，使量子逻辑能够使用光的粒子-光子-来操纵和传达这些杂质原子的量子状态。 这种方法非常适合扩大规模，以包括所需的构建块（杂质原子）的数量，以证明量子信息处理与当前社会普遍存在的数字经典信息处理相比的预测优越性。 这些电路的关键子组件是超紧凑的3维光学微腔，其中单独捕获的单光子可以相干地与同位原子杂质的电子态相互作用。 这些腔必须包含被捕获的光子达数百或数千个光学周期，以便电子状态和光子有效地耦合。 具有所需特性的腔体尚未在~ 2.9 µm波长下得到证实。 其他关键成分是原子杂质态本身，所谓的“深施主”，如S或Se。 西蒙弗雷泽大学的研究人员已经表明，硅中施主杂质的电子自旋状态编码的信息可以存储的时间比以前报道的任何固态系统都要长，只要找到耦合不同杂质原子的方法，就足以实现有效的量子信息处理。 我们的方法是使用2.9微米波长的光子，使用硅光子波导路由，在放置在上面讨论的高质量微腔中的原子之间传递这种量子信息。 如果成功的话，这项技术将可能为真正可扩展的量子信息处理平台开辟最令人兴奋的途径之一。 它可以在短期内彻底改变量子密码学和量子通信协议，同时可能在长期内支持完整的通用量子计算。 量子信息处理本身代表了本世纪潜在的革命性、改变游戏规则的技术之一。

Our extensive experience in designing, fabricating, and optically manipulating planar-waveguide-based photonic circuits using silicon-on-insulator wafers operating at wavelengths near 1.5 µm will guide the development of similar circuits to be used at an operating wavelength of ~ 2.9 µm. This is motivated by one of the most exciting potential applications of silicon photonic circuitry, namely quantum information processing, and in particular by the recent discovery of optically active single atom-impurity sites in silicon that should, when combined with the elements we have previously developed, enable quantum logic to be performed using particles of light - photons - to manipulate and communicate the quantum state of these impurity atoms. The approach is well-suited for scaling up to include the number of building blocks (impurity atoms) needed to demonstrate the predicted superiority of quantum information processing as compared to the digital, classical information processing that pervades current society. The key sub-components of these circuits are ultra-compact 3-dimensional optical microcavities within which individually trapped single photons can coherently interact with the electronic states of the co-located atomic impurity. These cavities have to contain the trapped photons for 100's of thousands of optical cycles in order for the electronic states and photons to efficiently couple. Cavities with the required properties have not yet been demonstrated at wavelengths ~ 2.9 µm. The other key ingredients are the atomic impurity states themselves, so called "deep donors", such as S or Se. Researchers at Simon Fraser University have shown that information encoded in the electronic spin state of donor impurities in silicon can be stored for times longer than any previously reported solid state system, long enough to enable effective quantum information processing, so long as methods are found to couple distinct impurity atoms. Our approach is to use 2.9 µm wavelength photons, routed using silicon photonic waveguides, to communicate this quantum information between atoms placed within the high quality microcavities discussed above. If successful, this technology will potentially open one of the most exciting pathways towards a truly scalable quantum information processing platform. It could revolutionize quantum cryptography and quantum communication protocols in the shorter term, while possibly supporting full, universal quantum computation in the longer term. Quantum information processing itself represents one of the potentially revolutionary, game-changing technologies of this century.