Open AccessCoherent beam combining of high power broad-area laser diode array with a closed-V-shape external Talbot cavity
Author(s) -
Bo Liu,
Yun Liu,
Yehuda Braiman
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.007361
Subject(s) - laser linewidth , optics , laser , talbot effect , grating , physics , distributed feedback laser , laser beam quality , semiconductor laser theory , coherence (philosophical gambling strategy) , laser diode , vertical cavity surface emitting laser , coherence length , materials science , optoelectronics , laser beams , superconductivity , quantum mechanics
We have coherently combined a high-power broad-area laser diode array by using a feedback loop closed off-axis external Talbot cavity. The off-axis feedback from two gratings provides transverse-mode control of broad-area lasers. The Talbot configuration of the external cavity implements diffractive coupling among laser diodes. Feedback from two gratings increases external cavity quality factor and spectrum selection capability. As a result, spatial coherence was improved and spectral linewidth was narrowed down. The high visibility of the far-field profile indicates that high spatial coherence was achieved. We also observed symmetric far-field profiles indicating that laser array was phase locked to in-phase and out-of-phase super-modes, respectively. Transition between these super-modes was observed by tuning one grating's tilted angle.