Dual-module combination with littman crosstalk external cavity for narrow-linewidth blue diode laser

The dense spectral beam combination is vital for achieving high power and brightness output in diode lasers. High-power narrow-linewidth laser modules have been widely studied as the fundamental units. This study presents a dual-module shared external cavity linewidth compression structure with a transmission diffraction grating. With a driving current of 2.4 A and a cooling temperature of 20 C-degrees , the blue diode laser's external cavity achieved an output power of 49.8 W, a spectral linewidth of 0.321 nm, and a tuning range of 0.817 nm, with an external cavity spectrum locked efficiency of approximately 80.6 %. Additionally, it is observed that crosstalk has a significant influence on the linewidth of the two modules. When one module current locked at 2.4 A and the other increased from 0 A to 2.4 A, the linewidth was reduced from 0.377 nm to 0.321 nm, and linewidth locking was implemented over an output power range from 27 W to 49.8 W. This work reports the highest output power for a blue diode narrow-linewidth external cavity laser.