PICOSECOND LASER DYNAMICS OF GAIN-COUPLED AND INDEX-COUPLED INGAAS INGAALAS QUANTUM-WELL DISTRIBUTED-FEEDBACK LASERS/

High frequency modulation of gain-coupled (GC) and index-coupled (IC) InGaAs/InGaAlAs distributed feedback (DFB) Lasers is investigated. Las er dynamics of conventionally fabricated IC DFB lasers are compared wi th GC DFB lasers realized by the new technology of masked implantation enhanced intermixing. Band structure dependence of the modulation res ponse at low temperature (T=2K) is analyzed by detuning the emission e nergy of the DFB lasers with respect to the gain maximum using differe nt grating periods. Pulse widths decreasing from 53 ps down to 4.5 ps with increasing emission energy demonstrate the capability of both cou pling types. The experimental results are in excellent agreement with a theory without any fit parameter based on laser rate equations. (C) 1995 American Institute of Physics.