Mode-coupling-induced dispersion has been used to engineer microresonators for soliton generation at the edge of the visible band. Here, we show that the optical soliton formed in this way is analogous to optical Bragg solitons and, more generally, to the Dirac soliton in quantum field theory. This optical Dirac soliton is studied theoretically, and a closed-form solution is derived in the corresponding conservative system. Both analytical and numerical solutions show unusual properties, such as polarization twisting and asymmetrical optical spectra. The closed-form solution is also used to study the repetition rate shift in the soliton. An observation of the asymmetrical spectrum is analysed using theory. The properties of Dirac optical solitons in microresonators are important at a fundamental level and provide a road map for soliton microcomb generation in the visible band.

模式耦合引起的色散已被用于设计微谐振器，以在可见带的边缘产生孤子。在这里，我们证明以这种方式形成的光学孤子类似于光学布拉格孤子，更笼统地说，类似于量子场论中的狄拉克孤子。对光学狄拉克孤子进行了理论研究，并在相应的保守系统中得出了封闭形式的解。解析解和数值解都显示出异常的特性，例如偏振扭曲和不对称光谱。封闭形式的解还用于研究孤子中的重复率偏移。使用理论分析了不对称光谱的观察结果。