Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, United States.
Nano Lett. 2012 Jul 11;12(7):3562-8. doi: 10.1021/nl3011885. Epub 2012 Jun 6.
Photonic miniaturization requires seamless integration of linear and nonlinear optical components to achieve passive and active functions simultaneously. Among the available material systems, silicon photonics holds immense promise for optical signal processing and on-chip optical networks. However, silicon is limited to wavelengths above 1.1 μm and does not provide the desired lowest order optical nonlinearity for active signal processing. Here we report the integration of aluminum nitride (AlN) films on silicon substrates to bring active functionalities to chip-scale photonics. Using CMOS-compatible sputtered thin films we fabricate AlN-on-insulator waveguides that exhibit low propagation loss (0.6 dB/cm). Exploiting AlN's inherent Pockels effect we demonstrate electro-optic modulation up to 4.5 Gb/s with very low energy consumption (down to 10 fJ/bit). The ultrawide transparency window of AlN devices also enables high speed modulation at visible wavelengths. Our low cost, wideband, carrier-free photonic circuits hold promise for ultralow power and high-speed signal processing at the microprocessor chip level.
光子学小型化需要将线性和非线性光学组件无缝集成，以同时实现被动和主动功能。在现有的材料系统中，硅光子学在光信号处理和片上光网络方面具有巨大的潜力。然而，硅的波长限制在 1.1μm 以上，并且不提供用于主动信号处理的所需的最低阶光非线性。在这里，我们报告了氮化铝（AlN）薄膜在硅衬底上的集成，为片上光子学带来了主动功能。我们使用 CMOS 兼容的溅射薄膜制造了具有低传播损耗（0.6dB/cm）的 AlN 绝缘体上波导。利用 AlN 的固有 Pockels 效应，我们演示了高达 4.5Gb/s 的电光调制，能量消耗非常低（低至 10fJ/bit）。AlN 器件的超宽透明窗口还实现了可见光波长的高速调制。我们的低成本、宽带、无载流子光子电路有望在微处理器芯片级实现超低功耗和高速信号处理。
