Fully-integrated Isolators for Silicon Photonics using WAMO (Wrap Around Magneto-Optics)

职务名称：使用WAMO（环绕磁光）的硅光子学完全集成隔离器摘要：非技术性：想象一个集成电路，其中光携带信号而不是电子。 这有望使许多信号更快地同时传输，并且没有热量。实现这种高密度“光子集成电路”的有效应用的主要缺失环节是集成隔离器。 隔离器使用磁光石榴石来控制光的方向，类似于电子器件中的二极管。虽然已经提出了几种集成隔离器，但它们并不适用于所有光偏振，实际上大多数仅适用于与所有硅集成激光器相反的偏振。 在这里，提出了新颖的隔离器，从一个独特的简单设计开始，具有很高的成功概率与今天的激光器，并逐步升级到最终的设计，包括一个集成的磁铁，并提供偏振多样性（这意味着所有的偏振可以隔离一个设备）。该项目的技术新奇有三个方面。首先，材料的挑战将克服磁光石榴石集成到硅。其次，新的硅光子设计将首先实现激光匹配偏振的隔离，然后实现所有偏振的隔离。第三，磁性设计将用于结合封闭的磁通结构，以磁化石榴石，同时最大限度地减少设备之间的磁串扰。技术：光子系统通过光纤保持社会联系，并通过光学互连保持计算机内部。光子学还影响医学、化学和许多其他领域。 集成隔离器是在具有完全集成激光源的光子系统成为现实之前需要解决的缺失环节，这意味着这里的结果将产生非常广泛的影响。 制造非互易器件（如隔离器）的唯一无源（零功率）方法是使用非互易（磁光）材料。磁光石榴石（例如，铈掺杂的钇铁石榴石）产量数量级优于任何其他材料的性能。然而，这些石榴石难以与硅集成为单相膜，并且多相会导致损耗。此外，迄今为止提出的隔离器设计对于实际实现来说太大，并且它们大多在仅应用于横向磁极化的几何结构中使用非互易相移，而集成激光器仅输出横向电光。在这里，经过验证的高回转性，低损耗和硅集成石榴石薄膜（Stadler）与新型硅光子设计（Li）的结合将确保全无源硅隔离器具有偏振多样化功能。 将探索三个层面的创新。首先，提出了一种横向电隔离器，其中石榴石沉积在干涉仪的分支之间以提供简单的不对称性，使得在一个施加的磁场下，将发生“推挽”非互易横向电相移。下一层创新将应用上述基本光子结果，并将扩展设计以包括集成的静磁工程磁偏置。具体而言，闭合通量回路结构（类似于闭合马蹄形磁体）将用于磁化石榴石覆层，而不需要外部场并且在电路中不产生边缘场。实现偏振分集的最后一步是一个接近封闭的通量设计，这将产生第一个在全无源、全集成隔离器中提供偏振分集的器件，该隔离器具有环绕磁光。

Title: Fully-integrated Isolators for Silicon Photonics using WAMO (Wrap Around Magneto-Optics)Abstract: Nontechnical: Imagine an integrated circuit where light carries the signal rather than electrons. This promises to allow many signals to transmit faster, simultaneously, and without heat. The major missing link in achieving impactful applications of such "photonic integrated circuits" with high densities is an integrated isolator. Isolators use magneto-optical garnets to control the direction of light, similar to diodes in electronics. Although several integrated isolators have been proposed, they do not work for all light polarizations, and in fact the large majority only work for the polarization that is the opposite of all silicon-integrated lasers. Here, novel isolators are proposed starting with a uniquely simple design that has a high probability of success with today's lasers, and escalating to a final design that includes an integrated magnet and offers polarization diversity (meaning all polarizations can be isolated with one device). The technical novelty of this project are three-fold. First, materials challenges will be overcome to integrate magneto-optical garnets onto silicon. Second, new silicon photonic designs will initially enable the isolation of the laser-matched polarization and later the isolation of all polarizations. Third, magnetic design will be used to incorporate closed flux structures to magnetize the garnets while minimizing the magnetic cross-talk between devices.Technical: Photonic systems keep society connected with optical fibers and inside computers with optical interconnects. Photonics also impacts medicine, chemistry, and many other fields. An integrated isolator is the missing link that needs to be solved before photonic systems with fully-integrated laser sources can be a reality, and this means the results here will have very broad impact. The only passive (zero-power) way to produce a nonreciprocal device, such as an isolator, is to include a nonreciprocal (magneto-optic) material. Magneto-optic garnets (e.g., Cerium-doped Yttrium Iron Garnet) yield orders of magnitude better performance than any other material. However, these garnets are difficult to integrate with silicon as single phase films, and multiple phases cause loss. Also, isolator designs proposed to date are too large for practical implementation, and they mostly use non-reciprocal phase shift in a geometry that only applies to transverse magnetic polarizations while integrated lasers output only transverse electric light. Here, the combination of proven high-gyrotropy, low-loss, and silicon-integrated garnet films (Stadler) with novel silicon photonic designs (Li) will ensure all-passive silicon isolators with polarization diverse functionality. Three layers of innovation will be explored. First, a transverse electric isolator is proposed where garnet is deposited between the branches of an interferometer to provide a simple asymmetry such that, with one applied magnetic field, a "push-pull" non-reciprocal transverse electric phase shift will occur. The next layer of innovation will apply the fundamental photonic results from above and will extend the design to include an integrated magnetostatically-engineered magnetic bias. Specifically, a closed flux loop structure (similar to a closed horseshoe magnet) will be used to magnetize the garnet claddings without requiring an external field and without producing fringing fields in the circuit. The final step towards polarization diversity is a nearly closed flux design that will yield the first device to provide polarization diversity in an all-passive, fully-integrated isolator with wrap around magneto-optics.