Title

Incoherent Combining Of 100-W Yb-Fiber Laser Beams By Ptr Bragg Grating

Keywords

High-energy lasers; Incoherent beam combining; Photo-thermo-refractive glass; Volume diffractive elements

Abstract

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.

Publication Date

12-5-2003

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering

Volume

4974

Number of Pages

209-219

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1117/12.501670

Socpus ID

0344851692 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/0344851692

This document is currently not available here.

Share

COinS