PFI-TT: Reliable High-Power Circular-Beam Semiconductor Lasers

这一创新-技术转化伙伴关系(PFI-TT)项目的更广泛影响/商业潜力是展示了一种新型可靠、高光束质量的半导体激光器，能够在现有技术不使用外部系统的情况下在现有技术无法达到的功率范围内产生圆形、近乎理想的输出激光。以低得多的成本提供质量更高、近乎完美的激光，有望实现有益于社会的新应用：更快的数据网络、创新的医疗解决方案、增强的自动驾驶汽车安全性和改进的消费产品。这将通过消除包含额外光束退化的外部光学组件来实现。这些进步是因为更容易操纵和聚焦的光束产生了更强烈的激光聚焦光斑。所采用的新处理方法还将为提高未来光子集成电路的密度带来显著的额外承诺，这对于支持社会对互联网和数据中心应用的快速增长的需求至关重要。拟议的项目专门解决了大多数边缘发射二极管激光器的长期局限性-它们固有的不对称、高度椭圆形，因此输出光束在10-500 mW范围内存在像散(难以聚焦)。像垂直腔面发射激光器(VCSEL)这样的器件可以发出圆形输出光束，但最大输出功率被限制在~5-10 mW。提出的创新使用了一种新的方法来制造边缘发射激光器，采用了穿过有源电子-空穴复合区的深腐蚀，然后采用特殊的湿式热氧化工艺来改善腐蚀损伤，同时平滑和钝化腐蚀的侧壁。采用这种高折射率对比度设计，获得了比商用单模垂直腔面发射激光器功率高80倍的单模圆形输出激光器。该项目的重点是对带有刻面钝化涂层的封装激光器进行寿命测试，并展示其实现成功商业化所需的长寿命、连续运行(例如5,000-10000小时)的能力。将使用时间分辨光致发光来评估和优化氧化物-半导体界面特性；将表征包括散光在内的光束质量，并评估预期的高速RF调制性能。还将探索包括量子点有源区材料和原子层沉积介质在内的替代方法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this Partnerships for Innovation - Technology Translation (PFI-TT) project is the demonstration of a new class of reliable, high-beam-quality semiconductor lasers capable of producing a circular, nearly ideal output laser beam operating in a power range which is currently inaccessible by existing technologies without the use of external systems. Providing a higher quality, near perfect laser beam at much lower cost promises to enable new applications beneficial to society: faster data networks, innovative healthcare solutions, enhanced autonomous vehicle safety, and improved consumer products. This will be achieved by eliminating external optical components which incorporate additional beam degradation. These advances result from the more-easily manipulatable and focusable beam producing a more intense, laser focused spot. The new processing methods employed will also have significant additional promise for increasing the density of future photonic integrated circuits, critical for supporting society’s rapidly growing needs for internet and data center applications.The proposed project specifically addresses a long-standing limitation of most edge-emitting diode lasers – their inherently asymmetric, highly elliptical, and thus astigmatic (hard to focus) output beams in 10-500 mW range. Devices like vertical cavity surface emitting laser (VCSEL) can emit a circular output beam, but are limited to maximum output powers of ~5-10 mW. The proposed innovation uses a novel method to fabricate edge-emitting lasers, employing a deep etch through the active electron-hole recombination region followed by a special wet thermal oxidation process to ameliorate etch damage while smoothing and passivating the etched sidewall. With this high-index-contrast design, single-mode circular output lasers with powers 80 times greater than that of commercial single-mode VCSELs have been achieved. The focus of this project is to lifetest packaged lasers with facet passivation coatings and demonstrate their capability for long-life, continuous operation (e.g., 5000-10000 hours) as required for successful commercialization. The oxide-semiconductor interface properties will be assessed and optimized using time-resolved photoluminescence; beam quality including astigmatism will be characterized, and the expected high-speed RF modulation performance evaluated. Alternative approaches including quantum-dot active region material and atomic layer deposition dielectrics will also be explored.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.