Analysis of frequency chirp in DFB lasers integrated with external modulators

A mathematical formulation for DFB semiconductor laser integrated with external modulators is developed and presented. A set of rate equations governing the interaction between the field and the carrier in the DFB laser under the influence of the optical feedback from the modulator is established. Analytical expressions for the modulation-induced frequency chirp in the DFB lasers are derived. Characteristics and parameter dependences of the frequency chirp are examined.<>