On‐chip stimulated Brillouin scattering (SBS) that results from enhanced light–sound interactions, has recently demonstrated great applicability and versatility for signal generation and manipulation. Progress toward realizing fully integrated Brillouin photonic circuits is promising; however, the control and routing of on‐chip optical waves requires non‐reciprocal elements such as circulators, which is challenging and adds complexity. Here, a circulator‐free Brillouin photonic planar waveguide circuit which eliminates the need for separate non‐reciprocal elements is demonstrated. Backward inter‐modal Brillouin scattering (BIBS) is used in a planar photonic integrated circuit, for the first time, to provide Brillouin processing capability in a multi‐modal waveguide, conveniently allowing for the separation of counter‐propagating pump and signal using passive integrated mode‐selective filters. Using an As₂S₃–Si hybrid multi‐modal photonic circuit, inter‐optical‐mode energy transfer with a Brillouin gain coefficient of 280 m⁻¹W⁻¹ is experimentally demonstrated, representing two orders of magnitude enhancement compared to conventional optical fibers. This on‐chip BIBS circuit allows for independent routing of pump and signal waves, showing resilience to the cross talk. The experimental demonstrations provide an important basis for achieving fully integrated Brillouin photonic circuits without requiring on‐chip circulators and fine spectral filtering, opening a new dimension for studying spatial‐dependent photon–phonon nonlinear dynamics.

中文翻译：

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无循环器布里渊光子平面电路

片上受激布里渊散射（SBS）是由于光声相互作用增强而引起的，最近在信号产生和操纵方面显示出极大的适用性和多功能性。实现完全集成的布里渊光子电路的进展是有希望的。但是，片上光波的控制和路由需要不可逆的元件，例如环行器，这具有挑战性，并且增加了复杂性。这里展示了一种无循环器的布里渊光子平面波导电路，该电路消除了对单独的不可逆元件的需求。向后模态布里渊散射（BIBS）首次用于平面光子集成电路中，以在多模态波导中提供布里渊处理能力，使用无源集成模式选择滤波器可方便地实现反向传播泵和信号的分离。使用一个₂ S ₃ –Si混合多模态光子电路，布里渊增益系数为280 m ^-1 W ^-1的光模间能量转移得到了实验证明，与传统光纤相比，代表了两个数量级的增强。该片上BIBS电路允许泵浦和信号波的独立路由，显示出对串扰的回弹力。实验演示为实现完全集成的布里渊光子电路提供了重要基础，而无需片上环行器和精细的光谱滤波，为研究空间相关的光子-声子非线性动力学开辟了新的领域。