Abstract: A second-order multi-mode partial distributed feedback (p-DFB) laser having increased electrical-to-optical power conversion efficiency, stabilized wavelength and narrowed emission linewidth. The laser includes an abbreviated grating housed in the laser cavity that is separated from both the front-end and the back-end of the laser facets.

Abstract: The invention provides a grating for a distributed feedback laser having decreased diffraction loss with reduced +/?1 order diffraction and scattering loss resulting from the reduced imperfections in the grating fabrication. In various embodiments, the grating has a low duty cycle wherein the ratio of the length of the low-index portion ‘a’ to the length of the pitch of the grating ‘b’ is less than 0.5. Further, in some preferred embodiments, the invention includes a laser, the laser comprising a distributed feedback laser wherein the laser includes a grating having less diffraction and less scattering loss. In various exemplary embodiments, the grating is further a partial grating, thereby providing increased efficiency resulting from a decrease in first-order diffraction loss due to the grating being separated from the front and rear facets and in some exemplary embodiments being situated at the area of lowest electric filed.