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Proceedings Paper

High Power Diode Laser Research In Mitsubishi Electric
Author(s): Kenj i Ikeda; Hisao Kumabe; Hirofumi Namizaki; Wataru Susaki
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Paper Abstract

In practical uses, life time is an important parameter for high power diode lasers. In general, one can find out two components in degradation mode of the A1GaAs/GaAs lasers, that is, gradual and sudden increases of operation current to keep the output power constant. The gradual degradation might be due to increase of non-radiative recombination centers in an active region, or to some kinds of facet oxidation which results in slow reduction of reflec-tivity. In order to avoid or eliminate the gradual degradation, it has been required to reduce the mechanical stress and temperature rising and to passivate the facets. The sudden increase of operation current could be understood in terms of facet degradation, which is mainly caused by high optical power density. The most radical case is the so-called COD(catastrophic optical damage). The COD is one of thermal effects coming from local temperature rising attributed to self-absorption of light at the facet region where the population inversion is lost by fast surface recombination velocity. The COD level is increased by passivation of dielectric film such as Si3N4 or Al203 to 1.5-2.0 times higher than the bare facet. As absorption intensity at the facet is determined by not output power but inner power at the facet, the inner power is an essential parameter for high power diode lasers. Output power is varied by changing the facet reflectivity, even though the inner power is controlled to be same level. It is generally known that inner power density at passivated facet corresponds to approximately 2-3MW/cm2 . The relationship between output power Po and inner power Pi is expressed as

Paper Details

Date Published: 9 August 1988
PDF: 5 pages
Proc. SPIE 0893, High Power Laser Diodes and Applications, (9 August 1988); doi: 10.1117/12.944354
Show Author Affiliations
Kenj i Ikeda, Mitsubishi Electric Corporation (Japan)
Hisao Kumabe, Mitsubishi Electric Corporation (Japan)
Hirofumi Namizaki, Mitsubishi Electric Corporation (Japan)
Wataru Susaki, Mitsubishi Electric Corporation (Japan)

Published in SPIE Proceedings Vol. 0893:
High Power Laser Diodes and Applications
Luis Figueroa, Editor(s)

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