Coherence control in semiconductor laser light with optical feedback and current modulation

Tools

Duque-Gijón, María and Masoller, Cristina and Tiana-Alsina, Jordi; Cojocaru, Crina and Spadaro, Salvatore and Marciniak, Marian, eds. (2025) Coherence control in semiconductor laser light with optical feedback and current modulation. In: 2025 25th Anniversary International Conference on Transparent Optical Networks (ICTON). International Conference on Transparent Optical Networks . IEEE, ESP. ISBN 9798331597771 (https://doi.org/10.1109/icton67126.2025.11125070)

[thumbnail of Duque-Gijon-etal-ICTON-2025-Coherence-control-in-semiconductor-laser-light]
Preview
 Text. Filename: Duque-Gijon-etal-ICTON-2025-Coherence-control-in-semiconductor-laser-light.pdf
Accepted Author Manuscript
License: Creative Commons Attribution 4.0 logo
Download (4MB)| Preview

Abstract

When coherent laser light is used for illumination, it produces speckles that degrade image quality. To mitigate this effect, various strategies based on breaking the spatial coherence of the semiconductor laser light have been proposed. Optical feedback is known to induce different dynamical regimes in semiconductor lasers. Depending on the laser current and feedback parameters, it can reduce the laser linewidth but it may also cause mode-switching, multimode emission, and chaotic output, directly impacting the coherence of the emitted light. In strong optical feedback scenarios, increasing the current often leads to alternating regions of low and high speckle contrast, being the latter associated with single-mode emission. This study explores the effect of combining direct current modulation and optical feedback on speckle contrast reduction. We find that although modulation does not further decrease the minimum speckle contrast, appropriately modulation parameters can fully suppress regions of high speckle contrast.

CORE (COnnecting REpositories)