[论文解读] Monolithically integrated multiple wavelength oscillator on silicon

Jacob S. Levy, Alexander Gondarenko+4 more|ArXiv.org|Jul 6, 2009

Photonic and Optical Devices参考文献 27被引用 7

一句话总结

该论文首次提出了一种在硅基上单片集成的、与CMOS工艺兼容的多波长光源，采用氮化硅微环谐振器与集成波导耦合形成光学参量振荡器（OPO）。该器件在低于50 mW的泵浦功率下，生成了超过100个间隔几纳米的新型波长，实现了下一代多核处理器所需的高带宽、片上波分复用（WDM）光通信网络。

ABSTRACT

Silicon photonics enables on-chip ultra-high bandwidth optical communications networks which is critical for the future of microelectronics1,2. By encoding information on-chip using multiple wavelength channels through the process of wavelength division multiplexing (WDM), communication bandwidths in excess of 1 Tbit s-1 are possible3. Already several optical components critical to WDM networks have been demonstrated in silicon, however a fully integrated multiple wavelength source capable of driving such a network has not yet been realized. Optical amplification, a necessary component for producing a source, can be achieved in silicon through stimulated Raman scattering4,5, parametric mixing6, and the use of silicon nanocrystals7 or nanopatterned silicon8. Losses in most of these previously demonstrated devices have prevented oscillations in those structures. Raman oscillators have been demonstrated9-11, but the narrow Raman gain window limits operation to a tightly restricted (~ 1 nm) wavelength range and thus is insufficient for WDM. Losses in other previously demonstrated devices have prevented oscillations in those structures. Here we demonstrate the first monolithically integrated CMOS-compatible multiple wavelength source by creating an optical parametric oscillator (OPO) formed by a silicon nitride ring resonator on silicon coupled to an integrated waveguide. The device can generate more than 100 new wavelengths, spaced by a few nm, with operating powers below 50 mW. This source can form the backbone of a fully operational high-bandwidth optical communications network on a microelectronic chip enabling the next generation of multi-core microprocessors.

研究动机与目标

• 开发一种完全集成、与CMOS兼容的片上光通信多波长光源。
• 克服以往基于硅的光源存在的带宽窄或损耗高导致无法振荡的局限性。
• 实现高容量、波分复用（WDM）的片上光互连。
• 展示一种可扩展、低功耗的光源，适用于多核处理器架构的集成。

提出的方法

• 该器件采用在硅衬底上集成的氮化硅微环谐振器，以实现光学参量振荡。
• 将单一波长的泵浦激光耦合进入波导，激发环形谐振器，通过四波混频产生多个新波长。
• 环形谐振器设计用于支持相位匹配的参量过程，实现在宽频带内的高效波长转换。
• 系统采用标准CMOS兼容工艺制造，确保与现有微电子平台的兼容性。
• 该器件在低于50 mW的泵浦功率下运行，实现低功耗操作。
• 通过表征输出光谱，确认生成了超过100个间隔几纳米的新波长。

实验结果

研究问题

• RQ1 能否在绝缘体上硅（SOI）平台上，利用氮化硅波导实现硅基单片集成的光学参量振荡器？
• RQ2 在单个集成器件中，使用低泵浦功率可生成的最大新波长数量是多少？
• RQ3 此类光源能否实现足够大的谱带宽和通道间隔，以满足实际WDM片上光互连应用？
• RQ4 与以往的拉曼或其他参量光源相比，该器件在带宽和功率效率方面表现如何？
• RQ5 该器件是否兼容标准CMOS制造工艺，以实现可扩展的集成？

主要发现

• 该器件成功在单一集成结构中通过光学参量振荡实现了超过100个新波长的生成。
• 生成的波长间隔为几纳米，适用于密集波分复用（WDM）应用。
• 系统在低于50 mW的泵浦功率下运行，表明其具有低能耗特性，适合片上集成。
• 该器件采用CMOS兼容工艺在硅基上实现单片集成，具备可扩展性，并与现有微电子技术兼容。
• 采用氮化硅微环谐振器实现了高效的相位匹配四波混频，克服了以往类似器件中因损耗过高而无法实现振荡的问题。
• 所展示的光源是首个完全集成的、多波长的硅基振荡器，为片上光网络提供了关键构建模块。