GAIN-COUPLED DISTRIBUTED-FEEDBACK GAINAS-GAAS LASER STRUCTURES DEFINED BY MASKLESS PATTERNING WITH FOCUSED ION-BEAMS

First-order periodic gain modulation in GaInAs-GaAs laser structures h as been realized by maskless focused ion-beam implantation, The struct ures were implanted with Ga+-ions at an ion energy of 130 keV and a li ne dose of 1 10(7) 1/cm, The periodicity of the gratings was designe d for laser operation at 77 K and room temperature, With optical pumpi ng we have observed single-mode laser operation due to the distributed feedback effect at wavelengths between 849 nm and 944 nn at 77 K (gra ting periods between 124 and 140 mn) and between 954 nm and 1005 mm at room temperature (grating periods between 140 and 148 mn).