We demonstrate an optically pumped complex-coupled InGaN/GaN-based multiple-quantum-well distributed-feedback laser in the violet/blue spectral region. The third-order grating providing feedback was defined holographically and dry etched through a portion of the active region by chemically assisted ion-beam etching. Epitaxial overgrowth of the GaN waveguide completed the device structure without introducing dislocations, as shown by transmission electron microscopy. The laser emitted light at 392.7 nm with high side-mode suppression and a narrow linewidth of 1.5 Å. In contrast to Fabry-Pérot lasers fabricated from the same piece of material, only a very minor change in emission wavelength was observed when operating the device at higher pump intensities.Short-wavelength semiconductor lasers are very attractive light sources for both data storage and scanning applications. During the last few years, both pulsed and continuous-wave operation of InGaN/GaN-based blue lasers have been demonstrated at room temperature. 1,2 Most research groups have typically used sapphire substrates for GaN growth. However, the misorientation between the sapphire and the GaN cleavage planes does not readily permit cleaving of the facets. Dry-etched mirrors with highreflective coatings appear to work satisfactorily in this material system, 3 but there is still a certain need to improve the cavity properties of nitride lasers, especially as far as mode selection is concerned. The use of distributed feedback ͑DFB͒ has already been explored somewhat for the purpose of improved mode and wavelength stability. Consequently, optically pumped 4,5 and electrically injected DFB lasers 6 in the InGaN/GaN material system have been reported recently. These devices were based on index coupling between the forward and backward propagating modes, which usually leads to additional loss through scattering at the corrugated interface between the waveguide and the cladding layer. Also, index coupling tends to be weak for higher-order gratings with nonideal tooth shape. Hence, we describe in this letter the fabrication of a nitride-based multi-quantum-well ͑MQW͒ DFB laser with a complex-coupled ͑i.e., index-plus gain-coupled͒ third-order grating, which enables increased coupling strength and potentially lower threshold intensity.Fabrication of this device began with growth of a 4-mthick GaN:Si layer on c-face sapphire. On top of this layer, we grew a 500-nm-thick Al 0.08 Ga 0.92 N:Si lower cladding layer, a 100-nm-thick GaN lower waveguiding layer, and a 40-nm-thick active region with five In 0.1 Ga 0.9 N quantum wells ͑QWs͒ and GaN barriers. A 10-nm-thick Al 0.2 Ga 0.8 N:Mg overlayer and a 20-nm-thick portion of the GaN upper waveguiding layer completed this first growth step. The third-order grating with a period of 240 nm was then defined by holographic exposure by using two-beam interference with a 325 nm UV HeCd laser. Transfer into the semiconductor was achieved by dry etching in a chemically assisted ion-beam etching ͑CAIBE͒ system. 7 We then overgr...