An edge-emitting laser for generating single-longitudinal mode laser light at a lasing wavelength. A semiconductor active region amplifies, by stimulated emission, light in the laser cavity at the lasing wavelength. A first grating section adjacent to the active region and having a first reflectance and a first effective index of refraction. A second grating section adjacent to the active region and having a second reflectance and the first effective index of refraction. The first and second grating sections have a Bragg wavelength substantially equal to the lasing wavelength. A gratingless phase-shift section is disposed adjacent to the active region and between the first and second grating sections and has a second index of refraction different than the first index of refraction and a length sufficient to impart a phase shift for light at the lasing wavelength sufficient to achieve single-longitudinal mode operation.