基于射频调制技术的高速太赫兹量子级联激光器研制

The terahertz quantum-cascade lasers (THzQCL) based on intersubband transitions is the best THz source emitting light at frequency between 1 and 5 THz, due to the all solid state, wide frequency tuning and high output power properties. This project is aiming to develop high power THzQCLs, to achieve modulation and injection locking of coupled-cavity THzQCL with radio frequency (RF) injection, to develop the high-speed THzQCL-based communication systems. The main tasks of the project are listed in the following: (1) Optimize the THzQCL device parameters using the Monte Carlo method, and then grow the high quality THzQCL active region structure by the molecular beam epitaxy system, and finally fabricate high power (>50 mW) continuous wave THzQCL devices; (2) Systematically investigate the impedance match between the RF injection and the THzQCL device, the attenuation mechanisms of the RF signal. Based on the high power THzQCLs achieved in (1), setup the whole experimental platform of the RF injection of THzQCL to enable the GHz-level modulation and injection locking. (3) Apply the RF injection to the coupled-cavity THzQCL to demonstrate the more efficient modulation. The project is supposed to obtain excellent results on the above-mentioned three aspects. Especially the demonstration of RF injection and modulation of coupled-cavity THzQCL could be the pioneering work in China.

基于子带间跃迁的太赫兹量子级联激光器（THzQCL）由于其全固态、易调谐、高功率等特点是目前最好的能产生大于1 THz频率的THz源。本项目旨在高功率THzQCL研制、射频（RF）注入耦合腔THzQCL的调制与锁定、以及基于RF调制和耦合腔的高速THzQCL通信等方面进行交叉综合研究。具体内容具体包括：（1）采用蒙特卡洛方法优化设计THzQCL各参数，采用分子束外延方法生长高质量THzQCL有源区结构，研制高功率（>50mW）连续波THzQCL器件；（2）系统分析RF调制THzQCL的阻抗匹配、RF信号衰减机制。基于（1）中实现的高功率THzQCL器件，搭建完整的基于RF的THzQCL实验平台，实现GHz调制与锁定；（3）结合耦合腔器件结构与RF注入，实现更加高效的调制。本项目研究有望在上述三个方面取得重要成果，尤其RF调制耦合腔THzQCL实验工作在国内将具有开创性意义。

本项目针对高功率连续波太赫兹量子级联激光器展开系统研究，并结合耦合腔结构，实现高速射频注入调制，推动太赫兹技术基础与应用研究。取得的研究成果总结如下：.1. 从太赫兹量子级联激光器有源区结构设计、分子束外延生长、波导模式分布、器件工艺制程等方面展开系统研究，设计并制作高功率连续波太赫兹量子级联激光器，在1-5 THz范围内，实现80 mW高功率连续波输出，脉冲功率1.2 W。.2. 计算表征太赫兹量子级联激光器高速调制特性，设计射频注入调制方案，设计多模耦合腔结构，实现耦合腔量子级联激光器GHz量级高速调制。.3. 基于本项目中高功率连续波太赫兹量子级联激光器，在太赫兹激光器远场特性改善，太赫兹成像关键技术、高速太赫兹光探测、太赫兹主动/被动锁模、太赫兹光频梳及双光梳等热点研究领域取得突破。