Incoherent, optically coupled laser arrays with increased spectral width

Abstract

An optically uncoupled laser array is modified at its current confinement geometry to introduce nonuniformity in effective optical cavity width and/or length among the different lasers comprising the laser array. An array laser comprising a plurality of spaced lasing elements with an optical cavity for generating and propagating radiation under lasing conditions with each of the laser elements being optically uncoupled from one another is enhanced by an extended spectral emission linewidth and reduction in temporal coherence. This extended spectral emission linewidth and reduction in temporal coherence is accomplished by changing the gravity gain or loss for at least a majority of the laser elements relative to each other whereby a different longitudinal mode(s) of operation and frequency of operation exist for each such laser element. The enhancement may be accomplished, for example, by providing nonuniformity in the current confinement width or nonuniformity in the effective current pumped region or a change in optical cavity absorption loss for at least a majority of laser elements. Such nonuniformity or change may be randomly varying or monotonically increasing or decreasing across the laser elements of the array.