Very low threshold current operation of semiconductor ring lasers

Abstract

Semiconductor ring lasers with a threshold current as low as 12.5mA have been fabricated in GaAs/AlGaAs. The excess bending loss is calculated to 3dB/360/spl deg/ and found to be independent of the radius between 30p/spl mu/ and 145/spl mu/m. Kinks in the L-1 curve are explained by temperature-induced shifts of the mode position.