Researchers built a parity-time symmetric coupled-cavity system that merges comb generation and all-optical signal broadcasting into a unified process on a single chip, Nature Communications reported. The architecture relies on equally spaced exceptional points in the frequency domain to overcome long-standing trade-offs in microcavity design.
Chip-scale optical signal broadcasting replicates data across multiple wavelength channels using Kerr nonlinearity, making it critical for high-throughput optical computing and communication systems. High-quality microcavities boost weak optical nonlinearity, but Fourier reciprocity imposes a fundamental trade-off. That constraint historically prevented researchers from simultaneously generating multi-wavelength pumps, known as soliton frequency combs, and executing massive signal broadcasting within a single cavity.
By introducing exceptional points into the coupled-cavity design, the researchers bypassed the reciprocity trade-off. The resulting device achieved over 100 usable channels operating across a 200-nanometer bandwidth. System throughput reached terabit-per-second speeds, which exceeds the intrinsic cavity linewidth limit by three orders of magnitude.
To show practical utility, the authors demonstrated an optical convolutional accelerator. The demonstration establishes a non-Hermitian paradigm for processing signals on integrated photonic chips.
Zhuang Fan, Yukun Huang, and Wenchan Dong contributed equally to the work. Co-authors included Haodong Yang, Yizheng Chen, Hanghang Li, Nuo Chen, Heng Zhou, Jing Xu, and Xinliang Zhang. They represent the Huazhong University of Science and Technology, the University of Electronic Science and Technology of China, and Optics Valley Laboratory. Funding came from the National Natural Science Foundation of China, Hubei Provincial Natural Science Foundation, Natural Science Foundation of Wuhan, and Quantum Science and Technology-National Science and Technology Major Project.
