Half-wave phase shifts were fabricated in the center of second-order GaAs gratings, for use in surface-emitting, horizontal-cavity, semiconductor diode lasers ͑ϭ0.98 m͒. Incorporating such gratings in diode lasers with distributed-feedback ͑DFB͒ active regions and distributed Bragg reflectors ͑DBRs͒ is found to provide surface-normal, single-lobe beam emission, as predicted by theory. InGaAs/AlGaAs/InGaP, two-quantum-well structures are employed. A 500-m-long GaAs/ Au second-order grating with half-wave phase shift represents the DFB region, which provides feedback and unidirectional light outcoupling. GaAs/SiO 2 /Au, 500-m-long, second-order gratings are the DBR regions, on either side of the DFB region, which provide both frequency-selective feedback as well as unidirectional outcoupling. Lateral-mode control is achieved via a 2.5-m-wide ridge waveguide. Surface emission is obtained through a 80-m-wide window stripe in the metallization on the substrate n-side. Single-frequency lasing in an orthonormally emitted, single-lobe, diffraction-limited beam is obtained to 3ϫ threshold under pulsed-drive conditions ͑200 ns wide pulses, 1 kHz repetition rate͒. © 2003 American Institute of Physics. ͓DOI: 10.1063/1.1636248͔Monolithic surface-emitting ͑SE͒ diode lasers are preferred over edge-emitting ones for generating high ͑у0.5 W͒ cw coherent powers primarily because complete passivation of the emitting area ͑for reliable operation͒ is not needed, scalability at the wafer level becomes possible, and packaging is significantly simplified. Monolithic, vertical-cavity surface emitters ͑VCSELs͒ are useful for many applications, but are limited to low single-mode powers ͑р7 mW͒. External-cavity controlled VCSELs have demonstrated 1,2 high coherent powers ͑Ͼ0.5 W͒, but with low efficiency and in configurations of doubtful long-term reliability. Horizontal-cavity, SE devices incorporating second-order, index-coupled, distributed-feedback ͑DFB͒ gratings have been studied since the early 1970s, 3-9 and were found, both theoretically 8,10,11 and experimentally, 3,12,13 to favor lasing in an antisymmetric mode ͑i.e., a two-lobed beam pattern͒, since such a mode has the least radiation losses, and subsequently is the one favored to lase. Furthermore, due to strongly nonuniform guided-field intensity profiles, such devices become multimode via gain spatial-hole burning.Several approaches have been proposed and/or successfully implemented for obtaining symmetric-like mode operation ͑i.e., single-lobe beam pattern͒ 14 -18 or for forcing the devices to operate in the symmetric mode. 9,19 With the no- and the guided-field profile is substantially uniform, thus insuring single-mode operation to high powers.Here we present the demonstration of the proposed concept. That is, by fabricating a second-order semiconductor grating with a central phase shift, and incorporating it in a DFB/DBR laser structure with a second-order GaAs/Au DFB grating, we obtain surface-normal emission in a single-lobe, diffraction-limited beam pattern to at le...