THERE IS A NEED FOR SMALL, LIGHTWEIGHT, HIGH BRIGHTNESS LASER SOURCES FOR DEEP SPACE OPTICAL COMMUNICATIONS BETWEEN SPACECRAFT AND NEAR EARTH ORBIT SATELLITES.

THERE IS A NEED FOR SMALL, LIGHTWEIGHT, HIGH BRIGHTNESS LASER SOURCES FOR DEEP SPACE OPTICAL COMMUNICATIONS BETWEEN SPACECRAFT AND NEAR EARTH ORBIT SATELLITES. BECAUSE OF STRINGENT POWER AND VOLUME LIMITATION IN THESE DEEP SPACE PROBES, THE SEMICONDUCTOR LASER IS THE ONLY VIABLE CANDIDATEAS A LASER SOURCE. INDIVIDUAL SEMICONDUCTOR LASER DIODES CANNOT MEET THE OTHER REQUIREMENTS OF DEEP SPACE COMMUNICATIONS SUCH AS HIGH BRIGHTNESS AND LOW BEAM DIVERGENCE. HOWEVER, SIMICONDUCTOR LASER DIODE ARRAYS EMPLOYING COHERENT BEAM COMBINING CAN MEET ALL OF THE REQUIREMENTS. OUR SOLUTION TO DEVELOPING SUCH A LASER SOURCE IS TO UTILIZE AN EXTERNAL CAVITY TO OBTAIN A COHERENT OUTPUT FROM AN ARRAY OF SEMICONDUCTOR LASER DIODES. THIS CONCEPT IS WELL KNOWN. HOWEVER, WE WILL INCORPORATE NEW TECHNIQUES TO MINIMIZE THE SIZE AND WEIGHT WHILE OPTIMIZING THE OUTPUT OF THE LASER. WITH THIS NEW DESIGN, IT WOULD BE POSSIBLE TO OBTAIN UP TO 100 WATTS OF CW OUTPUT FROM A TWO-DIMENSION SEMICONDUCTOR LASER DIODE ARRAY MEASURING ONE CENTIMETER SQUARE WHICH MEETS THE REQUIREMENTS OF A DEEP SPACE MISSION.