Abstract-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 m DFB/DBR gratings, emitting at = 0 98 m, high ( 100 A/cm 2 ) intermodal discrimination 1 th is obtained. 1 th is enhanced to 225 A/cm 2 by introducing free-carrier absorption in the array-interelement regions.Index Terms-Active photonic crystals, distributed-feedback (DFB) lasers, phase-locked oscillators, semiconductor lasers, surface-emitting lasers. , and hexagonal-lattice gratings [4]. However, none of these devices have strong built-in dielectric structures for lateral-optical-mode control and stability, and as a result are vulnerable to temperatureand carrier-induced dielectric-constant variations [2], [3]. A good example of such behavior is the unstable resonator device [3], which, while operating single-mode to high peak-pulsed powers in a single, off-normal beam, can become multimode in continuous-wave (CW) operation due to thermal lensing.Here, we present a 2-D GSE structure which combines the strong built-in index guiding for lateral-mode control and stability of resonant-optical-waveguide (ROW) arrays [5], [6], with an inherently efficient single-lobe surface-emitting distributed-feedback (DFB)-type structure [7], [8]. The result is a device which holds the potential to achieve watt-range CW surface-emitted powers in a stable single mode. ROW arrays, which are in effect laterally resonant active photonic crystals [6], have demonstrated diffraction-limited-beam operation to very high pulsed (10 W) and CW (1.6 W) output powers due to their large lateral (effective) index steps and uniform lateral-field intensity profiles [6]. We have also shown that second-order DFB/distributed Bragg reflector (DBR) devices with central phaseshift can provide single-frequency single-lobe surface emission with high efficiency [7], [8]. The relatively uniform guided-field profile [in the active (DFB) region] makes the device invulnerable to gain spatial hole burning, thus ensuring stable operation to high drive levels above threshold. Recently, we demonstrated this concept with a ridge-guide for lateral-mode control [9]. Single-frequency lasing in an orthonormally emitted single-lobe diffraction-limited beam was obtained to 3 threshold from unoptimized devices.We theoretically show that inserting DFB/DBR gratings with phaseshift only in the elements of a ROW array provides a 2-D GSE device with both large intermodal discr...