Ryczko Krzysztof, Zielińska Agata, Sęk Grzegorz
Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
Materials (Basel). 2021 Feb 27;14(5):1112. doi: 10.3390/ma14051112.
The optical gain spectrum has been investigated theoretically for various designs of active region based on InAs/GaInSb quantum wells-i.e., a type II material system employable in interband cascade lasers (ICLs) or optical amplifiers operating in the mid-infrared spectral range. The electronic properties and optical responses have been calculated using the eight-band k·p theory, including strain and external electric fields, to simulate the realistic conditions occurring in operational devices. The results show that intentionally introducing a slight nonuniformity between two subsequent stages of a cascaded device via the properly engineered modification of the type II quantum wells of the active area offers the possibility to significantly broaden the gain function. A-3 dB gain width of 1 µm can be reached in the 3-5 µm range, which is almost an order of magnitude larger than that of any previously reported ICLs. This is a property strongly demanded in many gas-sensing or free-space communication applications, and it opens a way for a new generation of devices in the mid-infrared range, such as broadly tunable single-mode lasers, mode-locked lasers for laser-based spectrometers, and optical amplifiers or superluminescent diodes which do not exist beyond 3 µm yet.
基于InAs/GaInSb量子阱的有源区有多种设计，即一种可用于带间级联激光器（ICL）或在中红外光谱范围内工作的光放大器的II型材料系统，本文对其光增益谱进行了理论研究。利用八能带k·p理论计算了电子特性和光学响应，其中包括应变和外部电场，以模拟工作器件中出现的实际情况。结果表明，通过对有源区II型量子阱进行适当设计的修改，在级联器件的两个后续阶段之间有意引入轻微的不均匀性，有可能显著拓宽增益函数。在3-5μm范围内可实现1μm的-3dB增益宽度，这几乎比之前报道的任何ICL大一个数量级。这是许多气体传感或自由空间通信应用中强烈需要的特性，它为中红外范围内的新一代器件开辟了道路，如宽可调谐单模激光器、用于基于激光的光谱仪的锁模激光器，以及目前在3μm以上不存在的光放大器或超发光二极管。
