Fig. 1. VBG external cavity feedback wave locking principle

Fig. 2. Schematic diagram of the VBG wavelength locking device

Fig. 3. Schematic diagram of spectral detection device

Fig. 4. Wave lock spectra at rated current

Fig. 5. Laser spectra of free running state at different current（black line）and after VBG is added（red line）

Fig. 6. Spectrograms at different water cooling temperatures

Fig. 7. Stable lock-in diagram at different water cooling temperatures

Fig. 8. Lock-in diagram of distance change between VBG and SAC

Fig. 9. Power current curve and power ratio before and after wave locking