Design for high-power single-mode operation from 2-D surface-emitting ROW-DFB lasers

Stable single-mode single-lobe operation to high powers is predicted for two-dimensional surface-emitting lasers, if second-order distributed feedback/distributed Bragg reflector (DFB/DBR) gratings are preferentially placed in the elements of a resonant-optical-waveguide array. Beside their usual functions (i.e., feedback and outcoupling), the gratings act as an effective array-mode selector due to different interaction with the gratings of different array modes. The in-phase array mode is strongly favored to lase around its (lateral) resonance due to better field overlap with DFB region and lower interelement absorption loss than for nonresonant array modes. For 20-element arrays with 700/600 μm DFB/DBR gratings, emitting at /spl lambda/=0.98 μm, high (/spl sim/100 A/cm²) intermodal discrimination /spl Delta/J/sub th/ is obtained. /spl Delta/J/sub th/ is enhanced to /spl sim/225 A/cm² by introducing free-carrier absorption in the array-interelement regions.