EFFICIENT COUPLING OF GALLIUM ARSENIDE LASER DIODE OUTPUT INTO A FIBER OPTIC FOR REMOTE POWER TRANSMISSION

AN EFFICIENT OPTICAL POWER MODULE IS NEEDED AS THE MAIN COMPONENT IN A REMOTE ELECTRICAL POWER SYSTEM. THIS PROPOSAL OUTLINES THE DESIGN, CONSTRUCTION, AND CHARACTERIZATION OF A FIBER-COUPLED, GALLIUM ARSENIDE DIODE LASER POWER MODULE THAT WILL MEET OR EXCEED THE SPECIFICATIONS SET FORTH BY DARPA. THE POWER MODULE WILL CONSIST OF THREE 3 WATT GALLIUM ARSENIDE DIODE LASERS (9 WATTS TOTAL) COUPLED INTO A 400 UM DIAMETER FIBER OPTIC. THE OUTPUT POWER WILL BE IN EXCESS OF 7 WATTS (80% COUPLING EFFICIENCY) WITH A NUMERICAL APERTURE OF ROUGHLY 0.2. THE WALL PLUG EFFICIENCY WILL BE 10% DEFINED AS THE OPTICAL POWER EMITTED BY THE FIBER DIVIDED BY THE ELECTRICAL POWER (AT 120 VAC) REQUIRED TO OPERATE THE DEVICE. A NOVEL FEATURE OF THIS DESIGN IS THAT THE FIBER DIAMETER, OUTPUT NUMERICAL APERTURE, AND COUPLING EFFICIENCY ALL REMAIN ROUGHLY CONSTANT AS THIS DESIGN IS SCALED TO HIGHER POWER. WITH ADDITIONAL DIODE LASERS, THIS POWER MODULE WILL SCALE TO 25 WATTS OF EMITTED POWER. HIGH POWER FIBER OPTIC SOURCES OF DIODE LASER LIGHT HAVE STRONG COMMERCIAL APPLICATION IN THE AREAS OF REMOTE POWER TRANSMISSION, DIODE-PUMPED SOLID-STATE LASERS, AND LASER SURGERY. THE LOW OUTPUT DIVERGENCE OF THIS OPTICAL SOURCE WILL PERMIT HIGH INTENSITY FOCUSING AS WELL AS LOW-LOSS POWER TRANSMISSION OVER LONG DISTANCES.