64 Gbps Si photonic crystal slow light modulator by electro-optic phase matching

We demonstrate 64 Gbps operation in a compact Si photonic crystal optical modulator that employs meander line electrodes and compensate for the phase mismatch between slow light and RF signals. Although low dispersion slow light increases the modulation efficiency, maintaining a sufficiently wide working spectrum the phase mismatch becomes a limiting factor on the operation speed even when the phase shifter length is as short as 200 mu m. Meander line electrodes broke this limit and enhanced the cutoff frequency by up to 31 and 38 GHz using 50 Omega and 20 Omega termination resistors. respectively. This allowed to use a group index of slow light higher than 20 and greatly improved the quality of the modulation characteristics at 25 and 32 Gbps. Clear open eye was observed even at 40-64 Gbps. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

我们在一个紧凑的硅光子晶体光调制器中实现了64 Gbps的运行，该调制器采用了曲折线电极，并补偿了慢光和射频信号之间的相位失配。尽管低色散慢光提高了调制效率，但要保持足够宽的工作频谱，即使移相器长度短至200μm，相位失配也会成为运行速度的限制因素。曲折线电极打破了这一限制，使用50Ω和20Ω终端电阻分别将截止频率提高了31 GHz和38 GHz。这使得能够使用大于20的慢光群折射率，并极大地改善了25 Gbps和32 Gbps时的调制特性质量。即使在40 - 64 Gbps时也能观察到清晰的眼图。（根据美国光学学会开放获取出版协议条款，© 2019美国光学学会）