Optical confinement enhancement of AlGaN-based deep-ultraviolet laser diode by using asymmetrically wide waveguide layers

The performance of AlGaN-based deep-ultraviolet (DUV) laser diodes (LDs) was investigated by varying the thickness of the upper and lower waveguide (WG) layers. The results show that (1) the asymmetric wide WG layers structure with thick upper and thin lower WG layer can effectively reduce the optical field leakage in the active region and increase the optical confinement factor (OCF) by 31.66% compared to the traditional symmetric wide WG layers structure. (2) The asymmetric wide WG layers improve the stimulated recombination rate, and electro-optical conversion efficiency, increasing the slope efficiency (SE) of the LD to 1.69 W/A at a lower threshold current (Ith) of 30.46 mA. (3) The asymmetric wide WG layers limit the carrier loss, which is due to the improvement of the energy band variation.