We propose a simple photonic waveguide structure that exhibits light propagation modes with vanishing group velocity via mode degeneracy. This enables stationary inflection point dispersion leading to the frozen mode and a true time delay device suitable for ultra-wide-band beamforming for millimeter wave (mmWave) phased arrays. The structure consists of three silicon ridge waveguides in proximity with periodic gaps introduced in the outer waveguides to create a band gap. The structure is complementary metal–oxide–semiconductor compatible with a very small footprint of only about $56 \; {\unicode{x00B5}{\rm m}^2}$ and more resilient to fabrication uncertainties as compared to the previously studied structures. Simulation results show transmission of 70% of the incident wave for the frozen mode at the 1.55 µm (193.6 THz) wavelength through the waveguide. It also enables a delay-bandwidth product of 6.75 along with unprecedented frequency independent bandwidth of about 0.5 THz for RF-mmWave–terahertz beamforming.

中文翻译：

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耦合硅脊波导中的冻结模式，用于光学实时延迟应用

我们提出了一种简单的光子波导结构，该结构通过模式简并性以消失的群速度展现出光传播模式。这使固定的拐点分散成为冻结模式，并实现了适用于毫米波（mmWave）相控阵列的超宽带波束形成的实时延时设备。该结构由三个硅脊形波导组成，它们与在外部波导中引入以形成带隙的周期性间隙相邻。这种结构是互补的金属-氧化物-半导体兼容的，仅占约56美元的非常小的占地面积。{\ unicode {x00B5} {\ rm m} ^ 2} $与先前研究的结构相比，它对制造不确定性的适应能力更强。仿真结果表明，在冻结模式下，波长为1.55 µm（193.6 THz）的入射波中有70％的入射波通过波导传输。对于RF-mmWave-太赫兹波束成形，它还可以实现6.75的延迟带宽乘积以及前所未有的约0.5 THz的独立于频率的带宽。