HIGH DUTY CYCLE, HIGH BRIGHTNESS PULSED LASER DIODE

THE PROPOSED EFFORT IS TO ANALYZE, DESIGN, AND FABRICATE A PROTOTYPE NEAR-IR (800-900 NM) SEMICONDUCTOR LASER WHICH WILL HAVE HIGH RADIANCE AND HIGH DUTY CYCLE AND WILL MEET THE REQUIREMENTS OF A RAIL JAMMER. FROM WORK DONE BY SEO AND OTHERS, IT HAS NOT BEEN CONCLUSIVELY PROVEN WHETHER LASER DEGRADATION IS DUE TO HIGH CURRENT DENSITY OR EXCESSIVE OPTICAL FLUX AT THE LASER FACETS. THERE ARE CASES WHERE THERE IS NO DETECTABLE FACET DAMAGE. IN THE SINGLE QUANTUM WELL (SQW) SEMICONDUCTOR LASER, THE CURRENT DENSITY AND OPTICAL FLUX CAN BE VARIED INDEPENDENTLY BY EMPLOYING DIFFERENT LASER CAVITY LENGTHS. SEO WILL OBTAIN A SAMPLE LOT OF FOUR SQW LASERS HAVING DIFFERENT CAVITY LENGTHS. THESE WILL BE DIVIDED INTO THREE LOTS. THE FIRST LOT WILL HAVE THE NORMAL HIGH-REFLECTANCE COATING ON ONE FACET AND THE THE NORMAL UNCOATED CLEAVED FACET. THE SECOND LOT WILL BE THE SAME EXCEPT THAT THE UNCOATED FACET WILL BE COATED FOR VARIOUS REFLECTIVITIES WITH HIGH-DAMAGE-LEVEL, MULTILAYER, DIELECTRIC COATINGS. THE THIRD LOT WILL HAVE BOTH FACETS ANTI-REFLECTION COATED, AND THESE DIODES WILL BE USED IN AN EXTERNAL CAVITY. A PERFORMANCE PREDICTION WILL BE MADE USING A LASER MODELING SOFTWARE PROGRAM. THE EXPERIMENTAL MEASUREMENTS WILL BE COMPARED WITH THOSE PREDICTED BY THE LASER MODEL. THE RESULTS OF THIS PROGRAM WILL BE A BASIS FOR PHASE II, WHICH WOULD BE CONCERNED WITH THE DESIGN OF A PRODUCTION UNIT AND THE EXTENSION OF LASER WAVE LENGTH TO LONGER VALUES.