Fiber facet gratings for high power fiber lasers

0485692 - ÚFE 2018 RIV US eng C - Konferenční příspěvek (zahraniční konf.)
Vaněk, Martin - Vaniš, Jan - Baravets, Yauhen - Todorov, Filip - Čtyroký, Jiří - Honzátko, Pavel
Fiber facet gratings for high power fiber lasers.
Proceedings of SPIE - The International Society for Optical Engineering 2017. Vol. 10603. Bellingham: SPIE: The Society of Photo-Optical Instrumentation Engineers, 2017 - (Fliegel, K.; Páta, P.), č. článku 106030J. SPIE. ISBN 978-1-5106-1702-5. ISSN 0277-786X.
[Photonics, Devices, and Systems VII 2017. Prague (CZ), 28.08.2017-30.08.2017]
Grant CEP: GA TA ČR TH01010997; GA ČR GA15-07908S
Institucionální podpora: RVO:67985882
Klíčová slova: leaky-mode resonant gratings * finite.diferance time-domain method * sub-wavelength diffraction gratings
Obor OECD: Optics (including laser optics and quantum optics)

We numerically investigated the properties of diffraction gratings designated for fabrication on the facet of an optical fiber. The gratings are intended to be used in high-power fiber lasers as mirrors either with a low or high reflectivity. The modal reflectance of low reflectivity polarizing grating has a value close to 3% for TE mode while it is significantly suppressed for TM mode. Such a grating can be fabricated on laser output fiber facet. The polarizing grating with high modal reflectance is designed as a leaky-mode resonant diffraction grating. The grating can be etched in a thin layer of high index dielectric which is sputtered on fiber facet. We used refractive index of Ta2O5 for such a layer. We found that modal reflectance can be close to 0.95 for TE polarization and polarization extinction ratio achieves 18 dB. Rigorous coupled wave analysis was used for fast optimization of grating parameters while aperiodic rigorous coupled wave analysis, Fourier modal method and finite difference time domain method were compared and used to compute modal reflectance of designed gratings
Trvalý link: http://hdl.handle.net/11104/0280656