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Simultaneous frequency stabilization and high-power dense wavelength division multiplexing (HP-DWDM) using an external cavity based on volume Bragg gratings (VBGs)

 
: Hengesbach, S.; Klein, S.; Holly, C.; Witte, U.; Traub, M.; Hoffmann, D.

:
Postprint urn:nbn:de:0011-n-3829919 (9.8 MByte PDF)
MD5 Fingerprint: 9b39b26fa5d3e3d690118fd62ab5618e
Copyright Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Erstellt am: 26.4.2016


Zediker, M.S. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
High-Power Diode Laser Technology and Applications XIV : San Francisco, California, February 2016
Bellingham, WA: SPIE, 2016 (Proceedings of SPIE 9733)
Paper 97330K, 15 S.
Conference "High-Power Diode Laser Technology and Applications" <14, 2016, San Francisco/Calif.>
Englisch
Konferenzbeitrag, Elektronische Publikation
Fraunhofer ILT ()

Abstract
Multiplexing technologies enable the development of high-brightness diode lasers for direct industrial applications. We present a High-Power Dense Wavelength Division Multiplexer (HP-DWDM) with an average channel spacing of 1.7 (1.5) nm and a subsequent external cavity mirror to provide feedback for frequency stabilization and multiplexing in one step. The "self-optimizing" multiplexing unit consists of four reflective Volume Bragg Gratings (VBGs) with 99% diffraction efficiency and seven dielectric mirrors to overlay the radiation of five input channels with an adjustable channel spacing of 1-2 nm. In detail, we focus on the analysis of the overall optical efficiency, the change of the beam parameter product and the spectral width. The performance is demonstrated using five 90 μm multimode 9xx single emitters with M2≤17. Because of the feedback the lateral (multimodal) spatial and angular intensity distribution changes strongly and the beam parameter product decreases by a factor of 1.2 to 1.9. Thereby the angular intensity distribution is more affected than the width of the beam waist. The spectral width per emitter decreases to 3-200 pm (FWHM) depending on the injection current and the reflectance of the feedback mirror (0.75%, 1.5%, 4%, 6% or 8%). The overall optical multiplexing efficiency ranges between 77% and 86%. With some modifications (e.g. enhanced AR-coatings) we expect 90-95%.

: http://publica.fraunhofer.de/dokumente/N-382991.html