Complete linear optical isolation at the microscale with ultralow loss.
Complete linear optical isolation at the microscale with ultralow loss.
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DOI：
10.1038/s41598-017-01494-w
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发表时间：
2017-05-08
影响因子：
4.6
通讯作者：
Bahl G
中科院分区：
文献类型：
--
作者：
Kim J;Kim S;Bahl G
低损耗光隔离器和环行器是信号路由和保护的关键不可逆元件，但使用标准光子代工工艺，它们的芯片级集成尚不实用。芯片上磁光不可逆系统集成面临的重大挑战使得探索无磁替代方案势在必行。然而，这些方法都尚未证明在微尺度足迹上具有理想特性的线性光学隔离——同时结合大对比度和超低前向损耗——与标准波导材料中的光子集成具有基本兼容性。在这里，我们证明仅使用由单频激光器泵浦的回音壁微谐振器就可以在任何介质波导内获得完整的线性光学隔离。这种隔离源自基于相干光声相互作用的不可逆诱导透明度，以及源自行波布里渊散射相互作用的耦合，这打破了波导谐振器系统内的时间反转对称性。我们的结果表明，对于芯片级光子学来说，与材料无关和与波长无关的光学隔离比以前想象的要容易得多。
Low-loss optical isolators and circulators are critical nonreciprocal components for signal routing and protection, but their chip-scale integration is not yet practical using standard photonics foundry processes. The significant challenges that confront integration of magneto-optic nonreciprocal systems on chip have made imperative the exploration of magnet free alternatives. However, none of these approaches have yet demonstrated linear optical isolation with ideal characteristics over a microscale footprint – simultaneously incorporating large contrast with ultralow forward loss – having fundamental compatibility with photonic integration in standard waveguide materials. Here we demonstrate that complete linear optical isolation can be obtained within any dielectric waveguide using only a whispering-gallery microresonator pumped by a single-frequency laser. The isolation originates from a nonreciprocal induced transparency based on a coherent light-sound interaction, with the coupling originating from the traveling-wave Brillouin scattering interaction, that breaks time-reversal symmetry within the waveguide-resonator system. Our result demonstrates that material-agnostic and wavelength-agnostic optical isolation is far more accessible for chip-scale photonics than previously thought.