Optical isolators today are exclusively built on magneto-optic principles but are not readily implemented within photonic integrated circuits. So far, no magnetless alternative^{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22} has managed to simultaneously combine linearity (that is, no frequency shift), linear response (that is, input–output scaling), ultralow insertion loss and large directional contrast on-chip. Here we demonstrate an electrically driven optical isolator design that leverages the unbeatable transparency of a short, high-quality dielectric waveguide, with the strong attenuation from a critically coupled absorber. Our concept is implemented using a lithium niobate racetrack resonator in which phonon-mediated¹³ photonic Autler–Townes splitting^10,16,23,24 breaks the chiral symmetry of the resonant modes. We demonstrate isolators at wavelengths one octave apart near 1,550 nm and 780 nm, fabricated from the same lithium-niobate-on-insulator wafer. Linear isolation is demonstrated with simultaneously <1 dB insertion loss, >39 dB contrast and 10 dB bandwidth up to ~200 MHz.

今天的光隔离器完全建立在磁光原理上，但不容易在光子集成电路中实现。到目前为止，没有无磁替代品^{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22}设法同时结合线性度（即无频移）、线性响应（即输入-输出缩放）、超低插入损耗和片上大方向对比度。在这里，我们展示了一种电驱动光隔离器设计，该设计利用了短而高质量的电介质波导无与伦比的透明度，以及来自临界耦合吸收器的强衰减。我们的概念是使用铌酸锂跑道谐振器实现的，其中声子介导的¹³光子 Autler-Townes 分裂^10,16,23,24打破了共振模式的手征对称性。我们展示了在 1,550 nm 和 780 nm 附近相隔一个八度音程的隔离器，由相同的铌酸锂绝缘体晶片制成。线性隔离同时具有 <1 dB 插入损耗、>39 dB 对比度和 10 dB 带宽，最高可达 ~200 MHz。