The present invention provides for a semiconductor laser having a narrow linewidth and low power consumption for optical communication applications. According to various embodiments of the invention, a semiconductor laser is provided which includes a grating layer comprising a plurality of segmented gratings, each including a non-grating portion and a grating portion. The segmented gratings are configured to enhance a fundamental mode of the semiconductor laser while sufficiently suppressing modes other than the fundamental mode, providing a narrow linewidth for example. The segmented gratings are also configured to provide an effective length longer than an actual length of the semiconductor laser, leading to smaller device areas and corresponding lower power consumption. A photonic integrated circuit is also provided which includes a plurality of semiconductor lasers, consistent with the present invention, as well as additional optical elements, all provided on a single substrate.