Impact of External Reflected Light Injection on  ASE Spectra and Mode Hopping of Laser

This paper explores the impact of external reflected light injectionon the Amplified Spontaneous Emission (ASE) spectrum of lasers. When external reflected light enters the laser cavity, the relative intensities of adjacent longitudinal modes change from a smooth transition to a discontinuous variation. This affects the stability of the laser's output power during mode hopping, leading the laser cavity to choose a distant side mode instead of an adjacent mode. The paper analyzes thepossibleoptical paths within the laser cavity and proposes an effective programming algorithm, successfully predicting the ASE spectrum under different external cavity lengths. This enhances the comprehension of the ASE spectrum, offering a laser solution that reduces the mode hopping frequency by half, thereby providing valuable insights for optimizing laser design and enhancing stability in real-world applications.