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Coherence of a room-temperature CW GaAs/GaAlAs injection laser

Reisinger, Axel R. and David, C. D., Jr. and Lawley, K. L. and Yariv, Amnon (1979) Coherence of a room-temperature CW GaAs/GaAlAs injection laser. IEEE Journal of Quantum Electronics, 15 (12). pp. 1382-1387. ISSN 0018-9197.

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The temporal coherence of a stripe-geometry double-heterojunction GaAs/GaAlAs laser operating CW at room temperature was determined. A heterodyne detection scheme was used involving the mixing of the laser field with a frequency-shifted and time-delayed image of itself in an interferometer. Because the laser device oscillated in several longitudinal modes, the autocorrelation function of its output exhibited resonances for specific time delays. The rate at which the amplitude of these resonances decreased with increasing time delays provided a measure of an apparent coherence length associated with individual longitudinal modes. The coherence length, so defined, was found to increase linearly with drive current in excess of threshold. This observation is interpreted as evidence that the intrinsic linewidth of a longitudinal mode is inversely proportional to the coherent optical power in that mode. Apparent coherence lengths were a few centimeters for a few milliwatts of total optical power emitted per facet. For a perfectly balanced interferometer, a sharp heterodyne beat signal was also observed when the laser device was operated considerably below threshold, i.e., in the LED mode.

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Additional Information:© Copyright 1979 IEEE. Reprinted with permission. Manuscript received April 4, 1979; revised July 5, 1979. We are grateful to D.W. Bellavance for supplying the laser material used in this work, to W. Abercrombie for device fabrication and to S. Slingerland for assistance in some phases of the experiment. A. Reisinger wishes to thank F. Sutherland as well as E. Chua of OIS for help with the computer calculations and acknowledges useful conversations with D.J. Coleman, W.C. Scott, and M. deWit. Credit must be given to an anonymous reviewer for pointing out the potential importance of second order dispersion.
Issue or Number:12
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ID Code:12024
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Deposited On:20 Oct 2008 18:08
Last Modified:03 Oct 2019 00:24

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