High-side mode suppression ratio with a high-stability external-cavity diode laser array at 976 nm in a wide temperature and current range

A high-side mode suppression ratio (SMSR) and high-stability external-cavity diode laser array employing optical feedback from a volume Bragg grating (VBG) with 15% diffraction efficiency at 976 nm was investigated. Based on the transfer matrix method and on the multimode rate equation, the theoretical model for an external-cavity diode laser at 976 nm was built for different temperature and current values. Both the simulated and the experimental results show that the temperature and the current range of such laser array with a front end reflectivity (Rf) of 0.5% are 10 °C and 15 A broader than that for an external cavity with Rf = 2%. As a result, the external-cavity diode laser array at 976 nm with a Rf value of 0.5% exhibits a high stability in the temperature range of 15–35 °C and from 15 to 50 A. Moreover, it shows an SMSR higher than 30 dB and a power larger than 33.9 W at 50A.