Ring resonator enhanced mode-hop-free wavelength tuning of an integrated extended-cavity laser

Albert van Rees*, Youwen Fan, Dimitri Geskus, Edwin J. Klein, Ruud M. Oldenbeuving, Peter J.M. van der Slot*, Klaus-J. Boller

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Extending the cavity length of diode lasers with feedback from Bragg structures and ring resonators is highly effective for obtaining ultra-narrow laser linewidths. However, cavity length extension also decreases the free-spectral range of the cavity. This reduces the wavelength range of continuous laser tuning that can be achieved with a given phase shift of an intracavity phase tuning element. We present a method that increases the range of continuous tuning to that of a short equivalent laser cavity, while maintaining the ultra-narrow linewidth of a long cavity. Using a single-frequency hybrid integrated InP-Si3N4 diode laser with 120 nm coverage around 1540 nm, with a maximum output of 24 mW and lowest intrinsic linewidth of 2.2 kHz, we demonstrate a six-fold increased continuous and mode-hop-free tuning range of 0.22 nm (28 GHz) as compared to the free-spectral range of the laser cavity.
Original languageEnglish
Pages (from-to)5669-5683
Number of pages15
JournalOptics express
Volume28
Issue number4
DOIs
Publication statusPublished - 17 Feb 2020

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