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Proceedings Paper

Ultra-compact 'Spectrometer-in-Fiber' based on chirped filament-array gratings (Conference Presentation)

Paper Abstract

Femtosecond laser irradiation was applied to single-mode optical fiber (SMF450), embedding a filament array through the silica cladding and guiding core cross-section to form chirped Bragg gratings. Unlike the standard plane-shape fiber Bragg grating structures, the filament shape facilitated radiation mode scattering of guided light transversely out of the fiber cladding, while the azimuthal radiation zone was narrowed by the filament geometry, the cylindrical cladding focus, and the photonic stop band design. Chirping of the grating period further provided spectral focusing in the near zone of the fiber, permitting recording of high resolution spectra (~350 pm) over the 400 to 650 nm band with a CCD camera. A comparison of second (Ʌ=364 nm) and fourth-order (Ʌ=728 nm) Bragg gratings is presented. Two-dimensional filament arrays permitted tailoring of photonic bandgap effects to redirect the -1st order grating light into the +1st order, increasing the overall spectrometer efficiency.

Paper Details

Date Published: 9 March 2020
Proc. SPIE 11270, Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XX, 112700W (9 March 2020); doi: 10.1117/12.2551025
Show Author Affiliations
Abdullah Rahnama, Univ. of Toronto (Canada)
Keivan Mahmoud Aghdami, Univ. of Toronto (Canada)
Young Hwan Kim, Univ. of Toronto (Canada)
Erden Ertorer, Univ. of Toronto (Canada)
Peter R. Herman, Univ. of Toronto (Canada)

Published in SPIE Proceedings Vol. 11270:
Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XX
Peter R. Herman; Michel Meunier; Roberto Osellame, Editor(s)

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