PHASE AND BEAM LOCKING OF LASER DIODE ARRAYS USING PHASE CONJUGATE RESONATORS

PHYSICAL OPTICS CORPORATION PROPOSES AN INNOVATIVE TECHNICAL APPROACH TO ACHIEVE SIMULTANEOUS PHASE-LOCKING AND BEAM COMBINING OF A LASER DIODE ARRAY. THIS APPROACH RELIES ENTIRELY ON PHOTOREFRACTIVE PHASE CONJUGATE OPTICS, THUS AVOIDING THE ALIGNMENT SENSITIVITY OF OTHER EXTERNAL OPTICAL TECHNIQUES. ONE OF THE PRINCIPAL FEATURES OF A LASER WITH A PHASE CONJUGATE RESONATOR CAVITY IS THAT ITS OUTPUT IS VERY TOLERANT OF INTRACAVITY DISORIENTATION. THIS SUGGESTS THE POSSIBILITIES OF USING PHASE CONJUGATION TO COHERENTLY COUPLE THE GAIN MEDIA FROM SEVERAL DIODE LASERS TOGETHER IN A SINGLE PHASE CONJUGATE RESONATOR PRODUCING A DIFFRACTION LIMITED OUTPUT BEAM WHICH COMBINES THE POWER OF THE INDIVIDUAL LASERS. AN INNOVATIVE RING PHASE CONJUGATE CAVITY GEOMETRY AND A DOUBLE PHASE CONJUGATE GEOMETRY,UTILIZING SINGLE ELEMENT PHOTOREFRACTIVE BATIO3 CRYSTAL, ARE PROPOSED FOR THE LONG TERM STABLE LOCKING OF LASER DIODE ARRAYS WITH SINGLE MAIN LOBE OUTPUT. THESE CONFIGURATIONS CAN ACHIEVE SEVERAL IMMEDIATE ADVANTAGES BY OBTAINING A HIGH QUALITY LASER DIODE SOURCE AS A FUNDAMENTAL BUILDING BLOCK OF LASER COMMUNICATION SYSTEMS. THEY ARE: 1) HIGH POWER, HIGH-BRIGHTNESS LASER DIODE SOURCES WITH COMPACT SIZE; 2) ENVIRONMENTAL INSENSITIVITY AND HIGH BEAM QUALITY; AND 3) LONG LIFE TIME AND LOW POWER CONSUMPTION.