Versatile, fast and accurate frequency excursions with a semiconductor laser

• Main Authors: Llauze, Thomas, Montjovet-Basset, Félix, Louchet-Chauvet, Anne
• Format: Journal Article
• Language: English
• Published: 18-07-2024
• Subjects: Physics - Optics
• DOI: 10.48550/arxiv.2403.14365

Applied Optics, vol. 63, issue 19, pp.5192-5202 (2024) Achieving accurate arbitrary frequency excursions with a laser can be quite a
technical challenge, especially when steep slopes (GHz/$\mu$s) are required,
due to both deterministic and stochastic frequency fluctuations. In this work
we present a multi-stage correction combining four techniques: pre-distorsion
of the laser modulation, iterative correction, opto-electronic feedback loop
and feed-forward correction. This combination allows not only to compensate for
the non-instantaneous response of the laser to an input modulation, but also to
correct in real time the stochastic frequency fluctuations. We implement this
multi-stage architecture on a commercial DBR laser and verify its efficiency,
first with monochromatic operation and second with highly demanding frequency
excursions. We demonstrate that our multi-stage correction not only enables a
strong reduction of the laser linewidth, but also allows steep frequency
excursions with a relative RMS frequency error well below $1$%, and a laser
spectral purity consistently better than $100$~kHz even in the midst of
GHz-scale frequency excursions.