Thermal lensing in high-power ridge-waveguide lasers

The lateral farfield characteristics of ridge- waveguide (RW) lasers emitting around 1064 nm an output power of 1.3 W at an injection current of 2 A were measured and modeled. Due to trenches with widths between 2.5 and 20 mum defining the narrow RW, radiation leaks out into the outer regions which suppresses higher-order modes, but which can also lead to a double-peaked lateral farfield of the fundamental mode. A simple model taking into account the thermal lensing effect explains well the lateral farfield behavior observed.