Impact of temperature-induced optical wavelength detuning on the quantum dot distributed feedback lasers

Authors: Chu, Q., Li, J., Wang, W., Liang, N., Cui, X., Xu, X., Yao, Y., Wang, J., Wang, T., Zhang, J., Wang, Z., Duan, J.

Journal: Optics and Laser Technology

Publication Date: 01/11/2026

Volume: 203

ISSN: 0030-3992

DOI: 10.1016/j.optlastec.2026.115543

Abstract:

In this work, we experimentally investigate the static characteristics, optical noise and feedback dynamics of quantum dot distributed feedback (QD DFB) lasers over a temperature range from 20^∘C to 85^∘C. Our results reveal that laser performance is closely related to the value of optical wavelength detuning (OWD) between the material gain peak and the lasing wavelength. A smaller OWD leads to significant overall performance enhancements. At 20^∘C, the laser exhibits a large OWD of 21.9 nm, corresponding to a higher relative intensity noise (RIN) of −132.5 dB/Hz and a spectral linewidth of 35.6 MHz. Furthermore, when the feedback strength exceeds −16.7 dB, the laser shows a slight degradation in stability, evidenced by a broadened radio-frequency spectrum and a gradual decrease in side-mode suppression ratio. As the temperature increases above 55^∘C, the OWD gradually decreases toward zero, resulting in improved noise characteristics (RIN ≈ −149 dB/Hz) and a dramatic linewidth reduction by nearly three orders of magnitude. Under these conditions, the laser also maintains stable operation even under strong optical feedback of −5.8 dB. Through comprehensive analysis, the optimal operating temperature is identified to be around 70^∘C, where the OWD approaches zero. This study comprehensively reveals the profound impact of OWD on the characteristic metrics and feedback dynamics of QD DFB lasers across a wide temperature range, providing valuable insights for designing temperature-insensitive and isolator-free semiconductor laser sources for advanced photonic systems.

Source: Scopus