Sampled Bragg gratings in chalcogenide (As₂S₃) rib-waveguides

Abstract

We have written a sampled Bragg grating into a highly photosensitive chalcogenide (As(2)S(3)) rib-waveguide using a scanning Sagnac interferometer. The grating exhibits evenly spaced rejection peaks over a 40 nm bandwidth. We estimate the induced refractive index change of the waveguide to be over 0.03 by matching the measured spectrum to numerical solutions of the coupled mode equations while accounting for an induced chirp. The sampled Bragg grating presented is comparable in strength and bandwidth to the best sampled Bragg gratings obtained to date in silica optical fibre.

Sulphide GaxGe25−xSb10S65(x=,5) sputtered films: Fabrication and optical characterizations of planar and rib optical waveguides

“…5,45 It was also used to limit, for pure CF 4 , the too strong chemical etch of As 2 S 3 films leading to serious undercutting and very rough sidewalls of the waveguides. 46 The use of oxygen can be avoided in our case and allowed a better respect for the composition of the sulphide film limiting the formation of oxysulphide by oxygen diffusion into the film.…”

High Quality Comb Filters in Chalcogenide Rib Waveguides

“…The 3 dB spectral response extends over 60 nm with a central peak at 1551 nm. This represents and increase of 20 nm compared with our previous report [9] where we used a 25 ptm wide slits and a separate shadow-mask, although the depth of the transmission dips are shallower. However the average 3 dB bandwidth of the individual dips was 150 pm and this is four times smaller than achieved previously.…”

“…ISBN 978-0-9775657-3-3 The interferometer was the same as described in the earlier work [9]. The writing beams were scanned across the waveguide at 10 rtm/s for 60 minutes and the grating length was around 36 mm.…”

“…However the major challenge in writing small duty cycle gratings that fully exploit this high photosensitivity is maintaining uniformity along the grating. In previous experiments [9] we have reported the production of sampled Bragg gratings in As2S3 rib waveguides where the on-off modulation was obtained by placing a separate amplitude mask just above the waveguide surface to modulate the two interfering beams from a Sangac interferometer used to produce the grating. The problem of this arrangement is that any small error in parallelism between the mask and the waveguide surface results in walkoff between the interfering beams which limits the grating length.…”

Low cost polymer sampled waveguide Bragg grating fabricated by using contact lithography

“…SWBGs fabricated on the chalcogenide (As 2 S 3 ) rib-waveguides and silicon-on-insulator (SOI) waveguides have been proposed in Refs. [23] and [24], respectively. And recently a SWBG based on the silicon nitride waveguide has also been proposed [25].…”