Stripe-width dependence of threshold current for gain-guided AlGaInN laserdiodes

The threshold current density of narrow-stripe gain-guided nitride laser di odes increases very rapidly as the stripe width is made narrow. To examine this behavior, waveguide simulations, incorporating the complex refractive indices associated with optical gain, have been used to analyze the lateral optical modes of gain-guided laser diodes. Threshold current was then dete rmined from the gain-current relationship of our laser material, which was obtained experimentally. These evaluations reveal that gain guiding, couple d with a carrier-induced index depression, offer a reasonable explanation f or the rapid increase in threshold when the stripe width becomes less than 5 mu m. (C) 1999 American Institute of Physics. [S0003-6951(99)03003- X].