Semiconductor Devices for Control of Solid-State Laser Dynamics

这个项目研究了基于III-V和Si/Ge-半导体的新型半导体可饱和吸收结构，用于控制锁模固体激光器的动力学。其新奇之处在于额外的宽带吸收器层，该吸收器层集成到可饱和吸收体中，并允许通过光载流子注入或量子井饱和进行独立的外部损耗调制。这些器件将在先进的激光系统中进行设计、制造和测试，是半导体可饱和布拉格反射镜的延伸。这一扩展对于抑制锁模Q开关等不需要的激光不稳定性是必要的。因此，它应该会显著延长系统寿命，并可能将锁模固体激光器带到一个规格范围内，在这个范围内，它们可以被视为未来光通信系统的光源。此外，它还为实现极高的幅度稳定性和充分利用可饱和吸收体的非线性光学响应提供了可能性。由于具有高折射率对比度的Si/SiO_2-Bragg反射镜，Si/Ge技术为极宽频带或短脉冲锁模激光操作提供了可能性。有了这些吸收体，激光系统就可以工作在连续波锁模下，而不受其他激光参数的影响，如泵浦功率、重复频率、输出功率、模体积、上态寿命等。可以增强该操作模式以提取高峰值功率超短脉冲。在本项目中，该装置将应用于高重复频率激光器的锁模。该项目是半导体生长和器件制造材料科学领域的研究人员与在先进激光系统中表征和测试器件的研究人员之间的密切合作。

0322740KaetnerThis project investigates novel semiconductor saturable absorber structures based on III-V and Si/Ge- semiconductors for controlling the dynamics of mode-locked solid-state lasers. The novelty lies in an additional broadband absorber layer that is integrated into the saturable absorber and which allows for an independent external loss modulation by optical carrier-injection or quantum well saturation. The devices, which shall be designed, fabricated and tested in advanced laser systems, and are an extension of the semiconductor saturable Bragg mirror. This extension is necessary to suppress undesired laser instabilities like mode-locked Q-switching. Thus it should significantly increase the system lifetime and might bring mode-locked solid-state lasers in a specification range where they can be considered as a source for future optical communication systems. In addition it gives the possibility to achieve exceptionally high amplitude stability and to fully exploit the nonlinear optical response of the saturable absorber. The Si/Ge-technology offers the possibility for very broadband or short pulse mode-locked laser operation due to the high index contrast Si/SiO2-Bragg mirrors available in this technology. With these absorbers a laser system can be operated in the continuous wave mode-locked regime independent of its other laser parameters such as pump power, repetition rate, output power, mode volume, upper-state lifetime, etc. For some applications intentional mode-locked Q-switched operation is desirable. This mode of operation can be enhanced to extract high-peak power ultrashort pulses. In this project, the device will be applied to mode locking of high-repetition rate lasers. The project is a close cooperation between researchers in material science for semiconductor growth and device fabrication and investigators characterizing and testing the devices in advanced laser systems.