Narrow linewidth near-UV InGaN laser diode based on external cavity fiber Bragg grating
Antoine Congar, M. Gay, Georges Perin, Dominique Mammez, Jean–Claude Simon, Pascal Besnard, Julien Rouvillain, Thierry Georges, Laurent Lablonde, Thierry Robin, Stéphane Trebaol
Abstract
We realize a fiber Bragg grating InGaN-based laser diode emitting at 400 nm and demonstrate its high coherency. Thanks to the fabrication of a narrowband fiber Bragg grating in the near-UV, we can reach single-mode and single-frequency regimes for the self-injection locked diode. The device exhibits 44 dB side-mode suppression ratio and mW output power. Detailed frequency noise analysis reveals sub-MHz integrated linewidth and 16 kHz intrinsic linewidth. Such a narrow linewidth laser diode in the near-UV domain with a compact and low-cost design could find applications whenever coherency and interferometric resolutions are needed.