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...
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Veröffentlicht in: | Optics letters 1998-06, Vol.23 (11), p.825-827 |
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Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | 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. |
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ISSN: | 0146-9592 1539-4794 |
DOI: | 10.1364/OL.23.000825 |