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Shi, Jianmei; Yang, Chengao; Chen, Yihang; Wang, Tianfang; Yu, Hongguang; Cao, Juntian; Geng, Zhengqi; Wang, Zhiyuan; Wen, Haoran; Tan, Hao; Zhang, Yu; Jiang, Dongwei; Wu, Donghai; Xu, Yingqiang; Ni, Haiqiao; Niu, Zhichuan Source: High Power Laser Science and Engineering, 2024;

Abstract:

Power scaling in conventional broad-area (BA) lasers often leads to the operation of higher-order lateral modes, resulting in a multiple-lobe far-field profile with large divergence. Here, we report an advanced sawtooth waveguide (ASW) structure integrated onto a wide ridge waveguide. It strategically enhances the loss difference between higherorder modes and the fundamental mode, thereby facilitating high-power narrow-beam emission. Both optical simulations and experimental results illustrate the significant increase in additional scattering loss of the higher-order modes. The optimized ASW lasers achieve an impressive output power of 1.1 W at 4.6 A at room temperature, accompanied by a minimal full width at half maximum (FWHM) lateral divergence angle of 4.91°. Notably, the far-field divergence is reduced from 19.61° to 11.39° at the saturation current, showcasing a remarkable 42% improvement compared to conventional BA lasers. Moreover, the current dependence of divergence has been effectively improved by 38%, further confirming the consistent and effective lateral mode control capability offered by our design.

? The Author(s), 2024. Published by Cambridge University Press in association with Chinese Laser Press. (27 refs.)