Holographic concepts for analysing gain and refractive index dynamics in semiconductor lasers

用于分析半导体激光器增益和折射率动态的全息概念

• 批准号: 310973190
• 负责人: Professor Dr. Martin Hofmann
• 金额: --
• 依托单位: Lehrstuhl für Photonik und Terahertztechnologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/310973190?language=en
• 关键词: Holographic; concepts; analysing; gain; refractive

The goal of this research project is to develop and verify holographic concepts for simultaneous spatially and spectrally resolved analysis of the gain and refractive index dynamics in laterally multimode semiconductor lasers. For that purpose, we will continue to use holographic techniques. In the final step we aim to add a temporal resolution down to the picosecond range to the spectral and spatial resolution. In the first phase of this project, we could show that holographic concepts are well suited to analyze gain and refractive index dynamics in semiconductors with high precision. However, the results also provided unexpected problems for the analysis of laser diode devices which have to be solved first. These problems include the beam propagation through the waveguide of the diode, i.e. in- and outcoupling, an appropriate mode filtering, the exact determination of the input field, and providing a suitable reference for holographic measurements even under mechanical vibrations which are induced, for example, by the water cooling of semiconductor laser amplifiers. For these challenges we have developed appropriate solution concepts which shall be implemented in this continuation project. This includes modified in- and outcoupling optics with mode filters, concepts for determination of the optical input field into the diode, and a common path setup for a stable reference wave generation. Based on these improvements, we will set up an efficient, fast and in the first step stationary holographic characterization system for laser diodes that provides gain spectra, differential gain spectra, spectra for carrier induced refractive index changes, and spectra for the linewidth enhancement factor for the devices. This approach shall be implemented first for laterally single mode emitters and will then transferred to spatially extended emitters (broad area lasers, tapered amplifiers). In the last step, we will analyze how gain and refractive index dynamics can be determined time resolved by pulsed probe and reference fields. If this is possible, we aim to determine the best possible time resolution. The overall goal of this project is still to achieve with our holographic approaches a fundamental understanding of the gain and refractive index dynamics in semiconductor lasers. Based on that understanding we aim to find new approaches for an improvement of the device performance, for example concerning beam quality or short pulse generation.

本研究计画的目标是发展和验证全息概念，同时空间和光谱解析分析的增益和折射率动态的横向多模半导体激光器。为此，我们将继续使用全息技术。 在最后一步中，我们的目标是将时间分辨率降低到皮秒范围，以获得光谱和空间分辨率。在这个项目的第一阶段，我们可以证明全息概念非常适合于高精度地分析半导体中的增益和折射率动态。然而，这些结果也为激光二极管器件的分析提供了意想不到的问题，这些问题必须首先解决。这些问题包括通过二极管的波导的光束传播，即输入和输出耦合，适当的模式滤波，输入场的精确确定，以及即使在例如由半导体激光放大器的水冷却引起的机械振动下也为全息测量提供合适的参考。针对这些挑战，我们已经制定了适当的解决方案概念，并将在本延续项目中实施。这包括修改的输入和输出耦合光学与模式过滤器，概念的光输入到二极管的字段的确定，和一个稳定的参考波产生的公共路径设置。在这些改进的基础上，我们将建立一个高效、快速、第一步固定的激光二极管全息表征系统，提供器件的增益谱、微分增益谱、载流子诱导折射率变化谱和线宽增强因子谱。这种方法应首先用于横向单模发射器，然后转移到空间扩展发射器（宽面积激光器、锥形放大器）。 在最后一步中，我们将分析如何通过脉冲探测场和参考场的时间分辨来确定增益和折射率动态。如果可能的话，我们的目标是确定最佳的时间分辨率。这个项目的总体目标仍然是实现与我们的全息方法的增益和折射率在半导体激光器的动力学的基本理解。基于这种理解，我们的目标是找到新的方法来改善器件性能，例如关于光束质量或短脉冲产生。