Rectangular mesa shaped vertical cavity surface emitting laser with shallow surface relief

In order to realize the high-power narrow linewidth of vertical cavity surface emitting laser (VCSEL), the shallow surface relief rectangular structure (SR VCSEL) is designed. The difference of the current density distribution leads to the mode distribution different. Calculation results show that, compared with circular mesa VCSEL, the uniformity of the current density distribution of rectangular mesa VCSEL is not changed when the active area is increased. And theoretical results indicate that the threshold gain of high-order mode increases greater than that of the fundamental mode when etching shallow relief of surface. In the experiment, the power of 5.87 mW when current is continuous, spectral width of 0.1 nm, power polarization degree of 10, and transverse mode suppression ratio more than 30 dB are obtained.