Journal article
Single-mode operation of a laser-diode array with frequency-selective phase-conjugate feedback
A new technique for single-mode operation of laser-diode arrays is presented. A gain-guided GaAlAs laser diode array is coupled to an external frequency-selective phase-conjugate feedback system that contains a photorefractive barium titanate crystal, a Fabry-Perot etalon, and a spatial filter. The etalon is the key component, and it forces the array, which has low spatial and spectral coherence when it runs freely, to oscillate in a single spatial and a single longitudinal mode.
At a drive current of two times the threshold current, the far-field pattern is reduced to only 1.4 times the diffraction limit, the spectral bandwidth is less than 0.02 nm, and the coherence length is increased by a factor of 70. The technique has general validity and can be applied to various other multimode laser systems.
Language: | English |
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Year: | 1998 |
Pages: | 825-827 |
ISSN: | 15394794 and 01469592 |
Types: | Journal article |
DOI: | 10.1364/ol.23.000825 |
ORCIDs: | Petersen, P.M. |