两微米宽波段的高速硅基光调制技术研究

High-speed modulation in silicon is one of the enabling techniques in the next generation optical interconnects. While two-micron spectral band emerges as a new optical communication window, high-speed modulation in silicon is a key technology for practical optical interconnect in this waveband and has important applications. Compared with shorter wavelengths, research on silicon modulator at 2-um has higher scientific significance has due to the following advantages: higher modulation efficiency, lower free carrier absorption, lower latency, larger broader coupling bandwidth and so forth. In this project, we propose to study broadband and high-speed modulation in silicon at 2-um wavelengths. It includes: (a) Theoretical model on free-carrier dispersion effect in silicon P-N junction at two-micron spectral band. (2) Research on broadband and high-speed modulation based on Mach-Zehnder interferometer and microring resonator. (3) The coupling between silicon waveguide and hollow-core photonic bandgap fiber which can guide light at speed of light in vacuum and has a theoretically lowest loss (0.1 dB/km) at 2-um. Finally, we will realize a 2-um high-speed silicon modulator array chip which is interfaced with photonic bandgap fibers. This project has a positive impact on the research in 2-um silicon photonics and can provide potential technical solution for large-capacity optical interconnects.

高速硅基调制是下一代光互连的核心技术之一。随着2微米波段逐渐成为红外光通信的一个新窗口，该波段的高速硅基调制是使新波段光互连走向实用化的关键技术，具有重要的应用前景。与短波长相比，2微米波段的硅基调制器具有更高的调制效率、更低的自由载流子吸收、更小的延迟、更大的耦合带宽等优点，因此具有重要研究价值。本项目提出开展2微米宽波段高速硅基调制技术的研究，具体包括(1)该波段硅P-N结载流子调控理论模型的建立；(2) 基于Mach-Zehnder干涉、微环谐振腔的高速、宽带调制技术研究；(3)硅波导-空芯光子带隙光纤耦合问题的研究，这种光纤几乎真空导光，其最低理论损耗值 (0.1dB/km)在2微米。最终，研制出2微米波段高速硅基调制器的多通道阵列芯片并实现芯片与光子带隙光纤的耦合。本项目的研究将促进硅光子学在2微米新波段的发展，为超大容量光互连提供技术储备。

本项目面向2微米新波段光通信的应用场景，开展高性能硅基调制器研究。完成了马赫增德调制器、微环调制器及其芯片接口技术的研究。深入研究了2微米波长尺度下硅波导的载流子效应，建立了理论模型对载流子色散效应和载流子吸收效应进行分析。通过多次流片对调制器进行了实验研究和性能验证，实现了80Gbit/s的硅基调制速率，为2微米波段目前最高纪录。本项目的研究结果表明，2微米波段硅基调制器有望用于下一代新波段光通信。