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Proceedings Paper

Intrinsically matched 50-ohm laser arrays with greater than 100% quantum efficiencies for optically coupled transistors and low-loss fiber optic links
Author(s): Stephen G. Ayling; David R. Wight; Michael Allenson; Keith P. Hilton; Gilbert W. Smith
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Paper Abstract

A new concept for optical signal transmission and amplification has been demonstrated. By connecting the lasers of an integrated array in series, rather than the usual parallel connection, significant quantum gain has been achieved. The forward voltage, dynamic resistance and external incremental slope efficiency of the array are simply the sum of the characteristics of the individual laser elements. However, the threshold current is the same as that of a single laser, thus avoiding the very high threshold currents found for parallel laser arrays. By choosing the appropriate number of laser elements the dynamic resistance of the array can be made to equal 50 Ohms giving an intrinsic broadband match for RF modulation without needing any additional resistors or impedance matching circuitry. Thus we demonstrate a ten element AlGaAs laser array with a forward voltage of 15 Volts, a broadband (DC to 500 MHz) impedance of 50 Ohms and a slope efficiency of 4.97 W/A per facet. In combination with a photodiode this forms an optically coupled transistor with a current gain of 3 dB. Such laser arrays can be used in low loss fiber optic links where the increased quantum efficiency compensates for losses within the system, and broadband insertion gain is potentially feasible.

Paper Details

Date Published: 4 May 1998
PDF: 10 pages
Proc. SPIE 3285, Fabrication, Testing, Reliability, and Applications of Semiconductor Lasers III, (4 May 1998); doi: 10.1117/12.307608
Show Author Affiliations
Stephen G. Ayling, Defence Evaluation and Research Agency Malvern (United Kingdom)
David R. Wight, Defence Evaluation and Research Agency Malvern (United Kingdom)
Michael Allenson, Defence Evaluation and Research Agency Malvern (United Kingdom)
Keith P. Hilton, Defence Evaluation and Research Agency Malvern (United Kingdom)
Gilbert W. Smith, Defence Evaluation and Research Agency Malvern (United Kingdom)


Published in SPIE Proceedings Vol. 3285:
Fabrication, Testing, Reliability, and Applications of Semiconductor Lasers III
Kurt J. Linden; Mahmoud Fallahi; Kurt J. Linden; S. C. Wang, Editor(s)

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