High-Power, Phase-Locked Single-Frequency Arrays of Diode Lasers

反制导二极管激光器的Botez锁相阵列（即所谓的ROW阵列）已经证明了1-1.5W的衍射限制功率，这是全单片振荡器的最高相干功率。然而，这些设备没有单频输出，这阻碍了它们在许多应用中的使用。此外，目前它们的元素数量被限制在20个以内，这反过来又限制了相干功率的总量。本文提出：1)开发具有分布式反馈（DFB）内置结构的ROW阵列，用于纵向模式控制；2)在保持单一空间模式的同时，实现将数组元素数量从20个增加到40-80个的新概念。对于ROW-DFB阵列，提出的材料体系是InGaAs/InGaP/GaAs，这是一种无a1结构，可确保无缺陷再生、高效率、可靠性和低线宽增强因子。因此，20元ROW-DFB器件有望提供1W的单频、衍射限制波束操作，线宽= 50kHz。为了提高模间分辨能力，从而使20元以上器件的单空间模式阵列能够工作，提出了两个新概念：1)通过埋地衍射光栅的选择性反馈进行阵列（横向）模式选择，以及2)横向限制反射器（LRR）。这两个概念都依赖于ROW-DFB器件的单频特性。通过优先反馈对高阶阵列模式进行区分。该器件将采用金属有机化学气相沉积法进行晶体生长；光栅制造用电子束和/或x射线光刻和化学蚀刻；电子束光刻和优先蚀刻用于阵列图案的生成。理论分析和设计将采用陈旧阵列的矩阵公式、波束传播方法和一维和二维有限周期结构的块函数形式进行。ROW-DFB器件实际上是二维光子tonic晶格。他们的研究将为这种激光器的工作原理提供新的线索，并将激发人们对基于光子晶格的其他类型设备的兴趣。瓦特范围、单频、限衍射光束稳定光源的实现将对平行光信号处理、谐波转换蓝光的产生、环境监测中红外相干光的产生以及自由空间光通信产生重大影响。该研究项目与美国各大公司和实验室的光电研究和开发小组紧密合作，包括at&t；T贝尔实验室，Uniphase, New Focus， TRW和David Sarnoff研究中心。该计划的一个关键特点是在光电器件研究的这一重要领域培养研究生和本科生。＊＊＊

9522035 Botez Phase-locked arrays of antiguided diode lasers (so called ROW arrays) have demonstrated 1-1.5W of diffraction-limited power, the highest coherent powers for all-monolithic oscillators. However, the devices do not have a single-frequency output, which prevents their use in many applications. Furthermore, all the present time, their number of elements is limited to 20 ,which in turn limits the amount of coherent power. It is proposed here to: 1) develop ROW arrays with a distributed feedback (DFB) built-in structure for longitudinal-mode control; and 2) implement novel concepts for increasing the number of array elements from 20 to 40-80, while maintaining a single spatial mode. For ROW-DFB arrays the proposed material system is InGaAs/InGaP/GaAs, an A1-free structure that assures defect-free regrowths, high efficiency, reliability, and low linewidth enhancement factor. As a result 20-element ROW-DFB devices are expected to provide single-frequency, diffraction-limited-beam operation to 1W with linewidths of = 50kHz. In order to increase the intermodel discrimination, and thus allow for single-spatial mode array operation of devices with more than 20 elements, two novel concepts are proposed: 1) array-(lateral)-mode selection via selective feedback from a buried diffraction grating, and 2) laterally restricted reflector (LRR). Both concepts rely on the single-frequency nature of ROW-DFB devices. High-order array modes are discriminated against by preferential feedback. The devices will be made by using metalorganic chemical vapor deposition for crystal growth; e-beam and/or X-ray lithography and chemical etching for grating fabrications; and e-beam lithography and preferential etching for array pattern generation. Theoretical analysis and design will be performed employing the matrix formulation for antiquated arrays, the beam propagation method, and the Block-function formalism for 1-D and 2-D finite periodic structures. ROW-DFB devices are in effect 2-D pho tonic lattices. Their will shed new light on how such lasers work, and will spur interest in other classes of devices based on photonic lattices. The realization of watt-range, single-frequency, diffraction-limited-beam stable sources will have significant impact on parallel optical-signal processing, the generation of blue light via harmonic conversion, the generation of mid-IR coherent light for environmental monitoring, and free-space optical communications. This research program is strongly coupled to collaborative with optoelectronic research and development groups at various major US companies and laboratories, including AT&T Bell Labs, Uniphase, New Focus, TRW, and David Sarnoff Research Center. A key feature of the program is the training of graduate and undergraduate students in this significant area of optoelectronic device research. ***