Integration of a semiconductor quantum emitter and a lithium niobate frequency converter for telecom quantum light generation

Generation of quantum light deterministically and at telecommunications wavelengths has been an insurmountable challenge for execution of quantum networking protocols in a scalable manner, as telecom photons can travel with minimal loss through optical fiber networks, distributing quantum entanglement over long distances. Semiconductor quantumnbsp;dots have emerged as the most promising platform to generate entangled photons deterministically, enabling scalable quantum networking applications. However, highnbsp;qualitynbsp;quantum dots operate at wavelengths outside of the telecom bandwidth, and therefore, efficient and low-noise quantum frequency converters are needed to use these quantum emitters for quantum networking purposes.nbsp;To date, fiber-coupled deterministic entangled photon sources with high efficiency have not been demonstrated, not even at wavelengths other than telecom. This proposal focuses on developing such a source based on quantum dots, coupled to a frequency converter to enable low-loss fiber communications.The focus of thisnbsp;Phase I project is to show the feasibility of developing fiber-coupled quantum emitters and frequency converters separately, and thenbsp;feasibility for their integration. High-quality-factor optical cavities will be designed and fabricated that, when coupled to quantum dots, ensure efficient extraction of the quantum dot emission into a single-mode fiber. During a separate effort,nbsp;thenbsp;feasibility of a frequency converter will be studied,nbsp;based onnbsp;a material with ultra-low loss and high nonlinear coefficient, periodically poled thin-film lithium niobate. Thin-film lithium niobate has emerged as a promising platform for integrated quantum photonics, supporting functionalities such as low-loss routing, high-speed switching, and nonlinear quantum processes. Together with high-quality-factor optical cavities, the feasibility of deterministic generation of entangled photon pairs at telecom wavelengths will be shown during Phase I.nbsp;nbsp;nbsp;nbsp;