Longitudinal mode control in $20-30\ \mu\mathrm{m}$ long cavity GaN-based VCSELs with a curved mirror

A single cavity filtering mirror was used to demonstrate single longitudinal mode operation for a VCSEL with a
$\sim 25\ \mu \mathrm{m}$
cavity length. The 443.5 nm lasing peak had an SMSR of 42 dB at 9 mA, 70kA/cm2.