Non-reciprocal devices such as isolators and circulators are key enabling technologies for communication systems, both at microwave and optical frequencies. Although non-reciprocal devices based on magnetic effects are available for free-space and fibre-optic communication systems, their on-chip integration has been challenging, primarily due to the concomitant high insertion loss, weak magneto-optical effects and material incompatibility. We show that χ⁽³⁾ nonlinear resonators can be used to achieve all-passive, low-loss, bias-free non-reciprocal transmission for applications in photonic systems such as chip-scale LiDAR. A multi-port nonlinear Fano resonator is used as an on-chip, non-reciprocal pulse router for frequency comb-based optical ranging. Because time-reversal symmetry imposes stringent limitations on the operating power range and transmission of a single nonlinear resonator, we implement a cascaded Fano–Lorentzian resonator system that overcomes these limitations and substantially improves the insertion loss and operating power range of current state-of-the-art devices. This work provides a platform-independent design for non-reciprocal transmission and routing that is ideally suited for photonic integration.

诸如隔离器和循环器之类的不可逆设备是微波和光频通信系统的关键启用技术。尽管基于电磁效应的不可逆设备可用于自由空间和光纤通信系统，但它们的片上集成一直具有挑战性，这主要是由于伴随着高插入损耗，弱磁光效应和材料不兼容的缘故。我们证明χ ^（3）非线性谐振器可用于实现全无源，低损耗，无偏置的非互易传输，用于芯片级LiDAR等光子系统。多端口非线性Fano谐振器用作基于频率梳的光学测距的片上不可逆脉冲路由器。由于时间反转对称性对单个非线性谐振器的工作功率范围和传输施加了严格的限制，因此我们实现了级联的Fano-Lorentzian谐振器系统，该系统克服了这些限制，并大大改善了当前状态下的插入损耗和工作功率范围最先进的设备。这项工作为不可逆的传输和路由提供了独立于平台的设计，非常适合光子集成。