Fabrication of an InGaAs single quantum well circular ring laser by direct laser patterning

The fabrication of single quantum well (SQW) ridge waveguide ring laser in strained InGaAs is described which utilizes direct‐write laser lithography followed by cryogenic UV laser‐assisted etching. The laser has a threshold current of 270 mA and emits ∼14 mW of single‐frequency output.