Ultra-High-Capacity Optical Communications and Networking: Integrated Guided Wave Devices for Terabit per Second Optical Communications

该提案是应NSF 01-65“超高容量光通信和网络”的要求提交的。未来的光信号处理和通信系统将需要大规模集成光子器件。铁电氧化物是一种高度非线性的光学材料，具有显著的优点，特别是用作光波导时。 在高折射率对比度薄膜结构的形式中，可以潜在地实现高密度集成光学器件。薄膜波导中的电磁场的固有限制导致高功率密度和强光学非线性。然而，它们在薄膜波导结构中的应用受到限制，因为难以制备具有块状非线性光学特性的低损耗材料。然而，铁电体外延的最新进展表明，薄膜导波器件现在是可以实现的。本计画将探讨应用于微光子元件与积体光学系统之磊晶铁电氧化物薄膜波导结构。 所提出的工作建立在我们的示范低损耗外延铁电薄膜制备的金属有机气相外延（MOVPE）和大带宽导波电光调制器的示范。 MOVPE使得能够制备具有高电光系数的铁电氧化物，其不能作为大单晶获得。待研究的具体系统包括BaTiO 3和其他铁电体。薄膜导波电光器件包括马赫-曾德尔电光调制器和光束控制器件。将设计和制造带宽为20-100 GHz的薄膜调制器。通过使用高度非线性的铁电薄膜，带宽和工作电压的显着改善相比，传统的体铁电器件。将研究外延铁电体与硅集成的可行性。金属有机分子束外延（MOMBE）将用于形成低折射率，外延缓冲层，作为一个稳定的铁电氧化物和硅衬底之间的界面层。将使用传统和电子束光刻制造设备。微光子器件和系统的潜在应用是每秒太比特的光通信、局域网和光互连。

This proposal was submitted in response to the solicitation NSF 01-65 on "Ultra-High Capacity Optical Communications and Networking." Future systems for optical signal processing and communications will require large scale integration of photonic devices. Ferroelectric oxides have long been recognized as highly non-linear optical materials with significant advantages, especially when used as optical waveguides. In the form of high-index-contrast, thin film structures, high-density integrated optics can be potentially achieved. The intrinsic confinement of the electromagnetic field in the thin film guide leads to high power densities and strong optical nonlinearities. Their utilization in thin film waveguide structures, however, has been limited because of difficulties in preparing low loss materials with bulk-like non-linear optical properties. Recent advances in the epitaxy of ferroelectrics, however, indicate that thin-film guided -wave devices are now realizable. In the proposed program epitaxial ferroelectric oxide thin film waveguide structures for microphotonic devices and integrated optical systems will be investigated. The proposed work builds upon our demonstration of low loss epitaxial ferroelectric thin films prepared by metalorganic vapor phase epitaxy (MOVPE) and the demonstration of large band width guided wave electro-optic modulators. MOVPE enables the preparation of ferroelectric oxides with high electro-optic coefficients that are not available as large single crystals. Specific systems to be investigated include BaTiO3, and other ferroelectrics. Thin film guided wave electro-optic devices will be fabricated including Mach-Zehnder electro-optic modulators and beam steering devices. Thin film modulators with bandwidths of 20-100 GHz will be designed and fabricated. By using highly nonlinear ferroelectric thin films, significant improvements in bandwidth, and operating voltage are anticipated compared to conventional bulk ferroelectric devices. The feasibility of integrating epitaxial ferroelectrics with silicon will be investigated. Metalorganic molecular beam epitaxy (MOMBE) will be used to form low index, epitaxial buffer layers that act as a stable interfacial layer between the ferroelectric oxide and the silicon substrate. Devices will be fabricated using both conventional and e-beam lithography. Potential applications for microphotonic devices and systems are in terabit per second optical communications, local area networks, and optical interconnects.