Periodic waveguides for quantum communication

量子信息研究将通过开发一种新型计算机和提供由自然规律保证的通信安全，引领我们进入下一次技术革命。虽然目前还不清楚量子计算机将由什么构成，但毫无疑问，光将继续成为我们主要的通信载体。在从经典光通信到量子光通信的过程中，需要开发许多新的构建模块，本提案侧重于光粒子的新来源-光子。执行量子密码术需要单光子或纠缠光子对，这种技术允许双方在完全保密的情况下进行通信。非线性光转换可以产生纠缠光子对。在块状晶体中，这个过程效率很低。集成光学有望大幅提高产量，因此我们正在制造周期性结构的半导体波导，目标是生产高效、定制的纠缠光子对源。所产生的光子对的转换效率和光谱特性高度依赖于波导的特性。一个精确可调谐的近红外激光器将使我们能够测量波导的传输，作为波长和偏振的函数。我们研究的主要目标是实现高质量的纠缠，这直接关系到光子对的光谱特性。本提案中要求的非常灵敏的光谱仪将产生这一重要信息。这些最先进的工具将使加拿大在光学量子信息研究方面处于领先地位。

Quantum information research will lead us into the next technological revolution by developing a new kind of computer and providing communication security guaranteed by the laws of nature. While it isn't clear yet what a quantum computer will be made of, there is no doubt that light will continue to be our main communication carrier. In going from classical optical communication to quantum optical communication many new building blocks need to be developed and this proposal focuses on novel sources of light particles - photons. Single photons or entangled pairs of photons are needed to perform quantum cryptography, the technique that allows two parties to communicate in perfect secrecy. Entangled photon pairs can be produced by nonlinear optical conversion. In bulk crystals, this process is very inefficient. Integrated optics promise to increase the yield dramatically and thus we are fabricating periodically structured semiconductor waveguides with the goal of producing highly efficient, tailored sources of entangled photon pairs. The conversion efficiency and spectral properties of the created photon pairs are highly dependent on the properties of the waveguides. A precisely tuneable near-infrared laser will allow us to measure the transmission of our waveguides as a function of wavelength and polarization. The primary objective of our research is to achieve high quality entanglement, which is directly related to the spectral properties of the photon pairs. A very sensitive spectrometer requested in this proposal will yield this important information. These state-of the-art tools will give Canada a leading edge in optical quantum information research.