Semiconductor Optical Buffers Using Grating Slow-Wave Devices

使用光栅慢波器件的半导体光缓冲器

• 批准号: 0200365
• 负责人: Shun-Lien Chuang
• 金额: $ 30万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0200365&HistoricalAwards=false
• 关键词: Semiconductor; Optical; Buffers; Using; Grating

Optical buffering is essential to optical packet switch implementations which have been proposed worldwide to overcome future problems with large electronic packet switches. We propose to design and fabricate semiconductor-based optical buffers by using sampled gratings, Moir gratings, and chirped Moir gratings. These gratings will be fabricated using a new method to obtain a photonic bandgap-engineered material that has a large index contrast, which is essential for group velocity reduction in our proposed gratings. Optical fiber delay lines have been commonly used in recent years in the design of optical buffers, typically through a fiber loop with standard components such as optical isolators, 3-dB couplers, and semiconductor laser amplifiers for the gating, interconnection, and signal amplification. The fundamental difficulty facing the design of an optical buffer is that variable-length buffers must be implemented with delay lines; however, by their nature, fiber loop optical delay lines are of fixed length. Our proposed optical buffer, unlike fiber loop delay lines, is variable by using current injection. Another significant advantage is that other semiconductor optoelectronic and optical devices can be integrated with our proposed variable optical buffers since they are based on the same semiconductor III-V compounds. Our proposed tasks include the design and fabrication of sampled gratings, Moir gratings, and chirped Moir gratings as slow-wave devices. The wavelength range for our proposed devices will be centered at 1.5-1.6 micron wavelength. Sampled gratings and Moir gratings can be shown to have a large group delay factor when a large contrast in the refractive index is introduced. This large refractive index contrast will be achieved using our proposed semiconductor and oxide materials. This contrast is at least two orders of magnitude larger than that of the fiber gratings. A chirped Moir grating allows for a broader bandwidth for the pass band. A novel photonic bandgap structure will be fabricated using periodic buried AlOx channels with growth on a patterned substrate. The advantages of this structure include tight optical and electrical confinement with very low defect densities. One or multiple current sources can be applied to the gratings via the doped AlGaAs layer to change the refractive index in the slow-wave structures for controlling the buffer delay. Our research will lead to the realization of a new class of semiconductor optical buffers, which can be immediately integrated with many optoelectronic devices.

为了克服未来大型电子分组交换机的问题，世界各地都提出了光缓冲技术。我们建议使用采样光栅、莫尔光栅和啁啾莫尔光栅来设计和制造基于半导体的光学缓冲器。这些光栅将使用一种新方法制造，以获得具有大折射率对比度的光子带隙工程材料，这对于我们提出的光栅中的群速度降低至关重要。近年来，光纤延迟线已被广泛用于光缓冲器的设计中，通常通过光纤环路与标准组件，如光隔离器、3db耦合器和用于门控、互连和信号放大的半导体激光放大器。光缓冲器设计面临的基本困难是可变长度缓冲器必须用延迟线实现；然而，就其性质而言，光纤环路光延迟线是固定长度的。与光纤环路延迟线不同，我们提出的光缓冲器是通过电流注入来改变的。另一个显著的优点是，其他半导体光电和光学器件可以与我们提出的可变光缓冲器集成，因为它们基于相同的半导体III-V化合物。我们提出的任务包括设计和制造采样光栅、莫尔光栅和啁啾莫尔光栅作为慢波器件。我们提出的器件的波长范围将集中在1.5-1.6微米波长。当引入较大的折射率对比度时，采样光栅和莫尔光栅可以显示出较大的群延迟因子。使用我们提出的半导体和氧化物材料将实现这种大折射率对比度。这种反差至少比光纤光栅的反差大两个数量级。啁啾莫尔光栅允许更宽的带宽为通带。一种新型的光子带隙结构将利用生长在图像化衬底上的周期性埋置AlOx通道来制造。这种结构的优点包括紧密的光和电约束和非常低的缺陷密度。通过掺杂的AlGaAs层，可以在光栅上施加一个或多个电流源来改变慢波结构的折射率，从而控制缓冲延迟。我们的研究将导致实现一类新的半导体光缓冲器，它可以立即与许多光电器件集成。