Wavelength stabilization of an external cavity semiconductor laser array

Free running semiconductor Laser Diode Array (LDA) is subject to wide line width and peak wavelength drift. In order to overcome the drawbacks, an External Cavity Laser Diode (ECLD) is constructed by adopting a Volume Bragg Grating (VBG). The experiments show that, after using the VBG reflector, the output spectral width is reduced to 0.96 nm, which is narrower than its original free running value of 2.3 nm. In addition, within the variation range of the coolant temperature (14-31°C), the peak wavelength of the VBG external cavity LDA is stabilized at the Bragg wavelength (808 nm) of the VBG, and the spectral width is kept below 1.14 nm. Experiments also show that the peak wavelength and the line width of the VBG external cavity LDA have no observable changes when the drive current of the LDA is varied from 7 A to 13 A.