Rapid mode hopping identification and suppression for external-cavity diode lasers based on frequency scanning interferometry

Mode matching has proven effective in suppressing the mode hopping in external cavity diode lasers (ECDLs) without antireflection coating. However, prolonged operation of ECDLs is susceptible to mode hopping induced by fluctuations in the equivalent internal cavity length. In this study, we introduce a rapid mode hopping identification method by monitoring the first derivative of the frequency scanning interference signal. Subsequently, an adaptive mode hopping suppression method, based on the acquisition of a priori knowledge for the initial current traversal optimization range, is applied to ECDLs. The experimental results demonstrate a significant extension in the stable operation time of the ECDL by a factor of 17, surpassing 7 h using the proposed rapid adaptive mode hopping suppression method.