Compact fiber optic spectrometers formed by chirped diffraction gratings inscribed with a femtosecond laser platform

Jean-Baptiste Quélène; Matilde Sosa Martí; Romain Cotillard; Guillaume Laffont

doi:10.1117/12.2648049

14 March 2023 Compact fiber optic spectrometers formed by chirped diffraction gratings inscribed with a femtosecond laser platform

Jean-Baptiste Quélène, Matilde Sosa Martí, Romain Cotillard, Guillaume Laffont

Author Affiliations +

Proceedings Volume 12417, Optical Components and Materials XX; 1241708 (2023) https://doi.org/10.1117/12.2648049
Event: SPIE OPTO, 2023, San Francisco, California, United States

Abstract

Femtosecond laser point-by-point writing is a commonly used method for fabrication of Fiber Bragg Grating sensors dedicated to harsh environments, such as high temperature or irradiation. In addition, a femtosecond laser platform allows for inscription of compact fiber optic diffraction gratings that consist of micro-voids or filaments formed into the fiber core and cladding by focusing laser pulses using microscope objectives. Light propagating in the fiber is coupled to radiation modes due to Mie scattering, thus providing wavelength dispersion in free space. Chirping the grating period further allows focusing of the outcoupled light in a given plane. Such an all-fiber focusing grating forms a compact photonic device permitting its use for FBG sensor interrogation. In this paper, fabrication of such spectrometers operating at 850 and 1550 nanometers is described. A characterization setup allowing measurements of spectra of FBGs at those wavelength bands is presented, and results corresponding to various focusing distances, grating lengths and chosen microscope objectives are exposed. Azimuthal distribution of scattered light is discussed, as well as focusing distance versus grating period chirp and spectrometer resolution versus grating length. Finally, spectra reflected by pointby- point FBG sensors are presented, thus demonstrating the great potential interest of such gratings for FBG interrogation.

Conference Presentation

Citation Download Citation

Jean-Baptiste Quélène, Matilde Sosa Martí, Romain Cotillard, and Guillaume Laffont "Compact fiber optic spectrometers formed by chirped diffraction gratings inscribed with a femtosecond laser platform", Proc. SPIE 12417, Optical Components and Materials XX, 1241708 (14 March 2023); https://doi.org/10.1117/12.2648049

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available