COUPLED-POWER THEORY OF NONLINEAR DISTRIBUTED-FEEDBACK LASERS, YIELDING REDUCED LONGITUDINAL SPATIAL HOLE-BURNING

An analysis of the nonlinear distributed-feedback (DFB) laser action i s presented. A set of nonlinear coupled-power equations is derived. A general condition for a nonlinear DFB laser with reduced spatial hole burning (SHB) is obtained. It is shown that the elimination of SHB in DFB lasers can be achieved by introducing properly-chosen variations o f the coupling strength along the longitudinal direction; a novel comp lex-coupling AR-coated DFB laser diode is proposed as a result. It is also shown that the optical nonlinearity must be considered for the de sign of high-power laser structures with reduced SHB. (C) 1998 America n Institute of Physics. [S0003-6951(98)00625-1].