Narrow Linewidth Distributed Feedback Lasers Utilizing Distributed Phase Shift

2024/08/28 by Yiming Sun, Sun, Yiming, Bocheng Yuan +15
Engineering · #78 #FOS: Physical sciences #Optical Network Technologies #Optics (physics.optics) #Photonic and Optical Devices #Semiconductor Lasers and Optical Devices

paper · pdf · doi:10.48550/arxiv.2408.15738

openalex publication_date 2024/08/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

This study proposes and experimentally demonstrates a distributed feedback (DFB) laser with a distributed phase shift (DPS) region at the center of the DFB cavity. By modeling the field intensity distribution in the cavity and the output spectrum, the DPS region length and phase shift values have been optimized. Experimental comparisons with lasers using traditional π-phase shifts confirm that DFB lasers with optimized DPS lengths and larger phase shifts (up to 15π) achieve stable single longitudinal mode operation over a broader current range, with lower threshold current, higher power slope efficiency, and a higher side mode suppression ratio (SMSR). Furthermore, the minimum optical linewidth is reduced significantly, from 1.3 MHz to 220 kHz.

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