3 July 2003 Incoherent combining of 100-W Yb-fiber laser beams by PTR Bragg grating
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Proceedings Volume 4974, Advances in Fiber Lasers; (2003) https://doi.org/10.1117/12.501670
Event: High-Power Lasers and Applications, 2003, San Jose, CA, United States
Volume diffractive gratings (Bragg gratings) in photo-thermo-refractive (PTR) inorganic glass are proposed for incoherent laser beam combining because they have narrow spectral selectivity and diffraction efficiency greater than 95% from visible to near IR regions. They showed no laser-induced damage, no thermal lens, and no Bragg angle shift under CW Yb-fiber laser (1096 nm) irradiation at 100 kW/cm2. It opens the way to rugged, low-cost, efficient optics for high-power laser systems. Based on theoretical modeling of PTR Bragg gratings, we have designed a high-efficient technology for incoherent combining of two or several laser beams with certain wavelength shift. Two 100 W beams of Yb-fiber lasers in the range of 1080-1100 nm with the wavelength separation of 11 nm were combined with efficiency exceeding 75% while material losses did not exceed 2-4%. No fading or parameter change of PTR Bragg grating working in two 100 W beams were found. It was found that the process limiting efficiency of incoherent beam combining is the spectral widening of radiation of Yb-doped fiber lasers. At high power, their spectral width exceeds spectral selectivity of Bragg grating and causes a decrease of diffraction efficiency.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Igor V. Ciapurin, Igor V. Ciapurin, Leonid B. Glebov, Leonid B. Glebov, Larissa N. Glebova, Larissa N. Glebova, Vadim I. Smirnov, Vadim I. Smirnov, Eugeniu V. Rotari, Eugeniu V. Rotari, } "Incoherent combining of 100-W Yb-fiber laser beams by PTR Bragg grating", Proc. SPIE 4974, Advances in Fiber Lasers, (3 July 2003); doi: 10.1117/12.501670; https://doi.org/10.1117/12.501670

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