Stabilization of a 1.55 μm extended-cavity semiconductor laser by intracavity dynamic holography

Commercial grating-tuned single-mode extended-cavity semiconductor lasers (ECLD's) can be tuned over 100 nm around 1.55 mum. This continuous tuning with no mode-hopping requires delicate factory adjustments and a high mechanical stability. These constrains are relaxed by the adjunction of a photorefractive crystal inside the cavity which creates an adaptive spectral filter which decreases the loss of the lasing-mode and thus enhances its stability.