Nonlinear operation of a planar circular-crating DBR laser

An approximate method for the analysis of the nonlinear operation of a plan ar circular-grating distributed Bragg reflector laser is presented. The ana lysis is based upon vector-wave self-consistent coupled-mode equations modi fied to take into account gain saturation effects. With the help of an ener gy theorem and threshold held approximation, an approximate formula relatin g small-signal gain to the output power and laser parameters is derived. Th e laser characteristics obtained reveal behavior of the optimal coupling st rength of the Bragg reflector, which provides maximal power efficiency as a function of the laser parameters. It is also shown that the gain saturatio n effect provides mode selectivity in the laser structure.