Adaptive distributed-feedback semiconductor laser

To solve the difficulty in wavelength adaptability of external-cavity semiconductor lasers, external-cavity distributed feedback has been proven to be an effective method to achieve adaptive narrow-linewidth semiconductor lasers. For the structural design and precise manufacturing of adaptive semiconductor lasers, the principle of laser linewidth compression based on distributed feedback needs to be explored. In this article, we propose a theoretical model for analyzing the operational mechanism of the adaptive distributed-feedback semiconductor laser. Theoretical and experimental results show that achieving adaptive linewidth compression requires tens of or more feedback points. On the basis of sufficient feedback points, increasing the feedback length and ratio can achieve an ultranarrow laser linewidth and high side-mode suppression ratio. This work provides a model analysis tool for exploring the ideal configuration of adaptive narrow-linewidth semiconductor lasers, which paves the way for the design and manufacturing of high-performance semiconductor lasers.