发表机构
Cornell University; NTT Research, Inc.（康奈尔大学; NTT研究公司）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出免光刻原位光子逆向设计，利用可编程薄膜铌酸锂波导实现多种光子功能，无需制造迭代，并展示低串扰的模式操作与波长响应工程。
AI 中文摘要
逆向设计已成为纳米光子学中一种强大的工程方法，催生了超越人类直觉的非直观器件设计。然而，逆向设计器件一直受限于昂贵且耗时的制造迭代、仿真与现实的差距以及蚀刻器件的固定特性。另一方面，可编程光子学已成为一种在制造后修改光子器件功能的方法；近年来，自由形态可编程光子器件已扩展到具有许多自由度，原则上为可编程地实现传统线性光子功能的逆向设计提供了合适的平台。在此，我们演示了对单个自由形态可编程光子器件的原位训练，以实现多种功能，而这些功能在传统逆向设计范式中各自需要单独的器件来实现。我们的平台是薄膜铌酸锂平板波导，对二维平板的折射率具有完全可编程性，每个10^4有效像素的调谐范围高达1.7e-3。我们演示了4x4高斯模式置换、4x4厄米-高斯模式解复用和8x8高斯模式置换，最大串扰分别为-27dB、-13dB和-13dB，以及4x4矩阵-向量乘法。我们还进一步演示了光谱响应的工程化，展示了在1500-1600nm窗口内的波长无关操作以及1310nm和1550nm之间的波长解复用，最大串扰为-8.4dB。由于器件在制造后为每种功能重新配置，器件制造、表征和校准的投资可以分摊到器件最终用于的各种光子功能上。
英文摘要
Inverse design has emerged as a powerful engineering approach in nanophotonics, leading to devices with unintuitive designs that extend beyond human intuition. However, inverse-designed devices have been limited by costly and time-consuming fabrication iterations, simulation-reality gaps, and the fixed nature of etched devices. Separately, programmable photonics has emerged as an approach to modify the function of photonic devices after fabrication; recent free-form programmable-photonic devices have been scaled to have many degrees of freedom, in principle providing platforms well-suited for programmably realizing inverse design of conventional linear-photonic functions. Here we demonstrate in situ training of a single free-form programmable-photonic device to achieve a variety of functions that each would have been implemented in separate devices in the conventional inverse-design paradigm. Our platform is a thin-film lithium niobate slab waveguide with full programmability over the refractive index of the two-dimensional slab, with a tuning range of up to 1.7e-3 for each of the 10^4 effective pixels. We demonstrate 4 x 4 Gaussian-mode permutations, 4 x 4 Hermite-Gaussian mode demultiplexing, and 8 x 8 Gaussian-mode permutations, with maximum crosstalk of -27dB, -13dB, and -13dB, as well as 4 x 4 matrix-vector multiplication. We further demonstrate engineering of spectral responses, showcasing both wavelength-independent operation throughout the 1500-1600 nm window and wavelength demultiplexing between 1310 nm and 1550 nm, with maximum crosstalk of -8.4dB. Since the device is reconfigured for each function after fabrication, the investment in device fabrication, characterization, and calibration can be amortized across the various photonic functions the device is ultimately used for.
