Investigation of output nonlinearity mechanisms in gan-based blue laser diodes

A nonlinearity mechanism in GaN-based blue laser diodes (LDs) has been studied by light-current (L-I) measurement under different pulse width, the experiments and simulation results verified that the nonlinearity is caused by mode changing resulting from temperature distribution difference for different cavity length. Nonuniformity of temperature distribution along the ridge leads to the diversity of confinement factors of the ridge waveguide which inducing poor waveguide stability. We concluded that long cavity length could improve the linearity of our LDs by decreasing temperature difference and thermal resistance.