Novel rare-earth doped LiNbO3 thin-film platform for integrated photonics

这一提议旨在开发一种用于单晶薄膜NbO_3(或LN)中的稀土掺杂有源器件的新型材料平台，也称为绝缘体上的LiNbate(LNOI)。最近的研究表明，LNOI是制造超紧凑集成光学器件的优良衬底材料平台，使得高效电光调制器和非线性波长转换器的开发大大超过了标准LN集成光学器件已经非常良好的性能。在这个项目中，我们将探索在新开发的稀土掺杂LNOI平台上实现放大器和紧凑型激光器等增益元件的新可能性。这将使这种令人兴奋的新材料具有更高的功能，并开发远远超出当前最先进水平的有源设备。在这一活动中，键合前的扩散掺杂将允许定制具有不同掺杂浓度的衬底，避免了目前使用块状掺杂晶体作为起始材料时的限制。此外，我们还将研究薄膜LN中的光折变效应，并研究抗损伤离子的定制掺杂，以减少最近在LNOI上观察到的许多器件中的光学损伤效应。尤其是，我们希望实现以下目标：首先，我们将制备不同离子和浓度的稀土(RE)掺杂的不同薄膜LN衬底，并对其光学性质进行全面的表征。其次，这些样品将用于波导制造，采用精密切割、化学机械抛光和干法腐蚀等方法，分别获得直脊和弯曲结构，如环形谐振器结构。这些研究将为实现该项目的第三个目标铺平道路，即在这个新的RE：LNOI平台上首次演示超紧凑型光放大器和脊形波导激光光源。一方面，该项目将利用申请人在LN、LNOI和波导技术方面的广泛专业知识来进行集成光学。另一方面，由于低噪声噪声平台的各种具有挑战性的技术方面，我们将与美国哈佛大学的M.LončAr教授团队合作，该小组在基于低噪声噪声的光子电路制造方面取得了突破性成果，并对使用稀土掺杂低噪声噪声离子进行未来的应用有着浓厚的兴趣。此外，我们还将利用我们与山东大学的密切联系，特别是与陈芬芳教授和胡华辉教授两个研究小组的联系。两人都在LNOI的开发方面拥有丰富的经验，后者也是公司NanoLN的创始人和首席执行官，该公司是全球领先的LNOI基板商业供应商。

This proposal aims at the development of a novel material platform for rare-earth (RE) doped active devices in single-crystalline thin-film lithium niobate (LiNbO3 or LN), also called lithium-niobate-on-insulator (LNOI).Very recent investigations have shown that LNOI is a superior substrate material platform for the fabrication of ultra-compact integrated-optical devices, allowing for the development of, e.g., highly efficient electro-optical modulators and nonlinear wavelength converters significantly exceeding the already very good performance of standard LN integrated optics. In this project, we will explore the new possibility to achieve also gain elements such as amplifiers and compact lasers in a newly developed RE-doped LNOI platform. This will allow for an even higher functionality of this exciting new material and the development of active devices that go well beyond the current state-of-the-art. In this activity, diffusion doping prior to bonding will allow for tailored substrates with spatially varying dopant concentrations, avoiding the current limitations when using bulk-doped crystals as starting material. Furthermore, we will investigate photorefractive effects in thin-film LN and work on tailored doping with damage resistant ions in order to reduce optical damage effects observed in many of the devices demonstrated recently in LNOI.In particular, we want to achieve the following objectives: First, we will fabricate different thin-film LN substrates with rare-earth (RE) doping of various ions and concentrations and fully characterize their optical properties. Second, these samples will be used for waveguide fabrication applying methods like precision dicing, chemical-mechanical polishing, and dry etching, to obtain straight ridges as well as curved structures e.g. ring resonator structures, respectively. These investigations will pave the way to achieve the third target of this project, i.e. a first demonstration of ultra-compact light amplifiers and ridge waveguide laser sources in this new RE:LNOI platform. On the one hand, this project will make use of the extensive expertise on LN, LNOI and waveguide technology for integrated optics of the applicant. On the other hand, and because of the various challenging technological aspects of the LNOI platform, we will collaborate with the group of Prof. M. Lončar at Harvard University, USA, which has demonstrated breakthrough results on the fabrication of LNOI-based photonic circuits and has strong interest in the use of RE-doped LNOI for future applications. Furthermore, we will use our close contacts to Shandong University, in particular to the two research groups of Prof. F. Chen and Prof. H. Hu. Both have strong experience in the development of LNOI, with the latter being also the founder and CEO of company NanoLN, which is the leading commercial supplier world-wide of LNOI substrates.