Design of index-coupled DEB lasers with reduced longitudinal spatial hole burning

Methods for reducing or eliminating longitudinal spatial hole burning in antireflection-coated, index-coupled distributed feedback (DFB) lasers are discussed. It is shown that elimination of spatial hole burning in DFB lasers can be achieved by the introduction of well-chosen variations of coupling strength and/or internal absorption in the longitudinal direction. It is shown that a theoretical laser structure with uniform power can always be obtained by choosing two arbitrary functions. The authors describe some of the more basic solutions with uniform power. Practical approximations of these structures, their numerical modeling, and some methods to fabricate them are presented