Optimization of n-type waveguide structure for 980 nm diode laser

In order to raise the output power and lower the far field divergence angles of 980 nm diode laser, a high refractive index inner waveguide is introduced in the n-type waveguide structure, which is based on the asymmetric waveguide structure. The research is conducted by SimLastip. Meanwhile, the semiconductor laser is fabricated with the epitaxial layer grown by a solid source molecular beam epitaxy (MBE) system. The fabricated 980 nm laser diode with 100 m strip width and 1000 m cavity length has a threshold current of 97 mA and a slope efficiency of 1.01 W/A. When the injection current is 500 mA, the far field divergence angles are 29(vertical) by 8 (horizontal), which is consistent with the simulated result. The theoretical and experimental results indicate that the inner waveguide structure can achieve high power output, effectively reduce the far field divergence angle and improve the beam quality of the device.