Accession Number : ADA289373

Title :   High-Speed Coherent Laser Arrays.

Descriptive Note : Final rept. Jul 92-Jul 93,

Corporate Author : DAVID SARNOFF RESEARCH CENTER PRINCETON NJ

Personal Author(s) : Felisky, Marc K. ; DeFreez, Richard ; Abeles, Joseph H. ; Bechtle, Daniel W. ; Naravan, S. Y.

PDF Url : ADA289373

Report Date : NOV 1994

Pagination or Media Count : 54

Abstract : This research describes a novel approach to semiconductor lasers capable of ultra-high speed modulation. This approach uses the interaction between elements in a coherent diode laser array that results in lateral mode locking. This method potentially allows narrow-band modulation at rates above the relaxation oscillation frequency of the lasers, thus removing a major impediment to ultra-high speed modulation. Linearized analysis of coupled laser rate equations shows that the array can be asymptotically stable for values of the coupling attainable with index-guided lasers. The small-signal responsivity for a two-element array, for 180 deg out-of-phase/ modulation, extends far beyond the relaxation oscillation frequency when examining the optical output from a single element. Large-signal analysis using full rate equations were used to demonstrate schemes for utilizing these microwave frequency resonances for high-speed optical signal transmissions. It was shown that digital signals with bit rates many times the relaxation oscillation frequency could be transmitted. Using lasers with a 4-GHz relaxation oscillation frequency, it is theoretically shown that rates of > 25 Gb/s can be achieved. This scheme can also be used for encoding analog information using narrow band amplitude modulation. It was demonstrated that a 44 GHz carrier with a 1-GHz amplitude modulated envelope signal could be successfully implemented (same device parameters as used for the digital example).

Descriptors :   *COHERENCE, *ARRAYS, *LASERS, COUPLING(INTERACTION), FREQUENCY, OUTPUT, DIGITAL SYSTEMS, OPTICAL PROPERTIES, AIR, POLYMERS, HIGH VELOCITY, GALLIUM ARSENIDES, LIGHT, RATES, VOLTAGE, SEMICONDUCTOR LASERS, SEMICONDUCTOR DIODES, TIME, CODING, SPECTRA, ALUMINUM, SIGNALS, ELECTRODES, LINEARITY, RESONANCE, RELAXATION, EQUATIONS, MODULATION, INDIUM, ANALOG SYSTEMS, NEAR FIELD, CURRENTS, OSCILLATION, MICROWAVE FREQUENCY, NARROWBAND, AMPLITUDE MODULATION, MODE LOCKED LASERS, SILICON NITRIDES.

Subject Categories : Polymer Chemistry
      Inorganic Chemistry
      Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE