| 20080212635 | HIGH EFFICIENCY DISTRIBUTED FEEDBACK (DFB) LASER WITH LOW-DUTY CYCLE GRATING - 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. | 09-04-2008 |
