Femtosecond laser direct writing of multiwavelength Bragg grating waveguides in glass.
Novel Bragg grating waveguide structures have been fabricated in bulk borosilicate glass through a type II photosensitivity mechanism driven by single femtosecond laser pulses. Low-loss single-mode waveguides and narrow-linewidth Bragg gratings were generated simultaneously by forming an array of refractive index voxels in a single laser scan. Laser pulse duration is shown to significantly affect the grating strength and waveguide loss. Bragg wavelengths, defined by the periodicity of laser-modified volumes, were fully controlled by the sample scan speed to provide resonances anywhere in the 1200-1620 nm telecommunication bands. Four linear Bragg filters with distinct resonant wavelengths are presented that define the first demonstration of laser writing of multiple-wavelength and cascaded Bragg grating waveguides in a single process step.
Zhang
Haibin
H
Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada. haibin.zhang@utoronto.ca
Eaton
Shane M
SM
Li
Jianzhao
J
Herman
Peter R
PR