On-chip sources of entangled photons for quantum information processing
On-chip sources of entangled photons for quantum information processing
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用于量子信息处理的纠缠光子片上源
DOI：
10.11470/photo.220205
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Nobuyuki Matsuda
中科院分区：
文献类型：
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作者：
T. Nishikawa;M. Tsukakoshi;K. Goto;H. Murakami;Y. Kumagai;M. Uemukai;T. Tanikawa;and R. Katayama;Nobuyuki Matsuda
量子信息科学和技术是试图通过将量子力学的性质应用于信息理论来实现超越当前技术能力的信息和通信技术的研究领域。应用包括量子计算，量子通信和量子计量学[1，2]。有各种候选的物理系统来编码量子态，例如量子比特，它是量子信息处理的基本单位。其中，光波长区域的“光子”是一个很好的候选者，因为它们的退相干低，易于单量子比特状态操纵，并且可以在室温下操作。凭借这些，单光子被用于广泛的量子信息实验[3]。然而，由于光子不与其他光子相互作用，因此获得光子之间的大的非线性相互作用是具有挑战性的，这对于量子比特之间的逻辑门操作是必要的[4]。然而，通过测量[5，6]诱导有效非线性的方法开辟了使用线性光学的光子量子信息处理。最近，已经提出了可以潜在地显示出优于具有少至50个光子的经典计算机的计算任务[7，8]，随后提出了将其应用于量子化学计算的建议[9]。为此，重要的是开发能够同时产生许多不可区分的单光子的光源。此外，源与量子处理电路的兼容性也至关重要。在过去的十年中，已经进行了许多研究，以在芯片上使用光波导实现量子电路[3，10，11]。直觉上，这种方法有望导致小型化和更大规模的量子电路。同样重要的是，这样的集成电路使我们能够实现量子态操纵，这是很难实现的自由空间光学电路。例如，我们最近使用基于波导的马赫-曾德尔干涉仪开发了一种通用线性光学电路[10];由于相位不稳定性，在自由空间系统中构建该电路具有挑战性。为了适应这样一个有吸引力的平台，量子光源也应该是波导集成的。本文首先介绍了作为量子光源的光子对光源的类型和原理。接下来，我们描述了我们的光子对和量子纠缠源的芯片上使用硅波导的发展。
Quantum information science and technology is a research field that attempts to realize information and communication technologies beyond the capability of current technologies by applying the properties of quantum mechanics to information theory. The applications include quantum computation, quantum communications, and quantum metrology [1, 2]. There are various candidates of physical systems to encode quantum states, such as a quantum bit, which is the basic unit of quantum information processing. Among them,“photons” in the optical wavelength region are a good candidate because of their low decoherence, easiness of single-qubit state manipulation, and availability of room temperature operation. By virtue of these, single photons are used in a wide range of quantum information experiments [3]. However, because photons do not interact with others, obtaining large nonlinear interactions between photons is challenging, which is necessary for logic-gate operations between quantum bits [4]. Nevertheless, methods of inducing effective nonlinearity via measurement [5, 6] opened up photonic quantum information processing using linear optics. Recently, computational tasks that can potentially show superiority over classical computers with as few as 50 photons have been proposed [7, 8], followed by a proposal of their applications to quantum chemistry calculations [9]. For such purposes, it is important to develop a light source capable of generating numerous indistinguishable single photons simultaneously. In addition, the compatibility of the source with quantum processing circuits is also essential. In the past decade, many studies have been conducted to realize quantum circuits using optical waveguides on chips [3, 10, 11]. Intuitively, this method is expected to lead to miniaturized and larger-scale quantum circuits. It is also important that such an integrated circuit allows us to realize quantum state manipulation that is hard to achieve with freespace optical circuits. For example, we recently developed a universal linear optical circuit [10] using waveguide-based Mach-Zehnder interferometers; the circuit is challenging to construct in a free-space system due to phase instabilities. To fit into such an attractive platform, the quantum light source should also be waveguide integrated. In this paper, we first introduce the types and principles of photon-pair sources used as quantum light sources. Next, we describe our development of photon-pair and quantumentanglement sources using silicon waveguides on a chip.