Measurement of internal loss, injection efficiency, and gain for continuous-wave semipolar (202̄1̄) III-nitride laser diodes

Summary form only given. We present advances in the performance and characterization of semipolar (202̅1̅) III-nitride laser diodes. These include a high yield facet formation process giving highly vertical and smooth facets (<;1 ° from vertical and roughness 2.0 nm) produced by chemically assisted ion beam etching (CAIBE), leading to threshold currents as low as 3 kA/cm
²
and threshold voltages as low as 5.5 V for continuous wave laser diodes. Also, we present the experimental measurement of internal loss (9 cm
^-1
), injection efficiency (73%), and gain. The measured internal loss value shows good agreement with a calculated value of 9.5 cm
^-1
, enabling a breakdown of contributions of each layer to the total loss of the laser and identifying routes to new improvements.