Bao Peng, Yao Chunhui, Tan Chenxi, Yuan Alan Yilun, Chen Minjia, Savory Seb J, Penty Richard, Cheng Qixiang
Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK.
GlitterinTech Limited, Xuzhou, China.
Microsyst Nanoeng. 2025 Apr 3;11(1):58. doi: 10.1038/s41378-025-00911-9.
Silicon photonic switches are widely considered as a cost-effective solution for addressing the ever-growing data traffic in datacenter networks, as they offer unique advantages such as low power consumption, low latency, small footprint and high bandwidth. Despite extensive research efforts, crosstalk in large-scale photonic circuits still poses a threat to signal integrity. In this paper, we present two designs of silicon Mach-Zehnder Interferometer (MZI) switches achieving ultra-low-crosstalk, driven thermally and electrically. Each switch fabric is optimized at both the device and circuit level to suppress crosstalk and reduce system complexity. Notably, for the first time to the best of our knowledge, we harness the inherent self-heating effect in a carrier-injection-based MZI switch to create a pair of phase shifters that offers arbitrary phase differences. Such a pair of phase shifters induces matched insertion loss at each arm, thus minimizing crosstalk. Experimentally, an ultra-low crosstalk ratio below -40 dB is demonstrated for both thermo-optic (T-O) and electro-optic (E-O) switches. The T-O switch exhibits an on-chip loss of less than 5 dB with a switching time of 500 µs, whereas the E-O switch achieves an on-chip loss as low as 8.5 dB with a switching time of under 100 ns. In addition, data transmission of a 50 Gb/s on-off keying signal is demonstrated with high fidelity on the E-O switch, showing the great potential of the proposed switch designs.
硅光子开关被广泛认为是解决数据中心网络中不断增长的数据流量的一种经济高效的解决方案，因为它们具有诸如低功耗、低延迟、小尺寸和高带宽等独特优势。尽管进行了广泛的研究，但大规模光子电路中的串扰仍然对信号完整性构成威胁。在本文中，我们展示了两种实现超低串扰的硅马赫曾德尔干涉仪（MZI）开关设计，它们分别由热驱动和电驱动。每个开关阵列在器件和电路层面都进行了优化，以抑制串扰并降低系统复杂性。值得注意的是，据我们所知，这是首次利用基于载流子注入的MZI开关中固有的自热效应来创建一对能提供任意相位差的相移器。这样一对相移器在每个臂上引起匹配的插入损耗，从而将串扰降至最低。实验表明，热光（T-O）和电光（E-O）开关的串扰比均低于-40 dB。T-O开关的片上损耗小于5 dB，开关时间为500 μs，而E-O开关的片上损耗低至8.5 dB，开关时间不到100 ns。此外，在E-O开关上以高保真度演示了50 Gb/s开关键控信号的数据传输，展示了所提出的开关设计的巨大潜力。
