本项目拟以我们拥有自主知识产权的数字级联光栅布拉格反射器（DCG-DBR）调谐半导体激光器为基础，展开相关器件相位噪声的理论和实验研究。通过建立器件的噪声理论模型，研究调谐过程中附加相位噪声导致线宽展宽的物理机理。在此基础上，采用先进的实验手段，检测相位噪声，并提取附加噪声分量，对线宽展宽进行评价。提出采用多相移数字级联光栅反射器（MPSDCG）和热调谐机制相结合，探索抑制相位噪声有效途径，以实现窄线宽输出。.本项目以窄线宽可调谐光源为研究目标，将深入研究调谐半导体激光器的线宽展宽机理的基础研究与提升自主研发的DCG-DBR激光器性能的应用研究紧密结合、共同实施。通过该项目的研究，可以为研发窄线宽可调谐半导体激光器奠定先进的理论分析、实验测试、器件设计的基础。窄线宽可调谐半导体激光器在下一代高速相干光通信、高精度相干检测系统有重要应用价值。

In this project, we will focus on theoretical and experimental studies of excess phase noise l in the digital concatenated grating reflectors (DCR-DBR) tunable semiconductor laser, which is developed by ourselves and based on selves-owned IP. Specifically two main tasks will be involved: first, a phase noise model will be developed, to recognize linewidth broadening of such devices, and then phase noise will be characterized by using a novel detection technique for laser phase noise measurements and linewidth will be estimated; second, narrowing linewidth will be investigated by using digital concatenated grating with multiple phase shifts (MPSDCG) reflectors and thermal tuning mechanism. .The main overall objective of this project is to achieve narrow linewidth tunable semiconductor lasers, by carrying out studies on linewidth broadening of the devices, and combining with improvements on our DCG-DBR lasers. The output of this project will provide a good groundwork for developments of narrow linewidth tunable semiconductors in terms of analysis, characterization and design. Narrow linewidth tunable semiconductor lasers are key devices for high-speed coherent optical communication systems and high-resolution sensor applications.