High-Speed Coherent Laser Arrays.
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).
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1994
- Accession Number
- ADA289373
Entities
People
- Daniel W. Bechtle
- Joseph H. Abeles
- Marc K. Felisky
- Richard Defreez
- S. Y. Naravan
Organizations
- Sarnoff Corporation