High efficiency and a narrow spectrum spectral beam combining a module with a single grating external cavity.

A single grating multiple diffraction spectral beam combining (SBC) structure is proposed and demonstrated, which keeps high efficiency by using the methods of polarization separation and full feedback. The maximum combining efficiency is 81.1%, which leads to an output power of 12.3 W, and a spectrum width of 6.1 nm, under continuous wave operation at a current of 25 A. Compared to the combining efficiency of conventional SBC and double gratings SBC, the combining efficiency of this work is improved by 6%, and 17.3%, respectively. The results show that this believed to be novel SBC method is a prospective technique for increasing the combining efficiency of multiple diffraction SBC and getting a narrow spectrum.