Real-time observation of Bragg grating formation in As$_2$S$_3$ chalcogenide ridge waveguides
Real-time study of the formation of Bragg gratings in monolayer As<SUB>2</SUB>S<SUB>3</SUB> ridge waveguides is presented. A transverse holographic method is used to record such gratings. The periodic photodarkening of the layer leads to the formation of a Bragg grating with resonant wavelength ~1.55 mum. The experiment allowed to control in situ the grating parameters such as the reflectivity, the resonant wavelength (between 1500 and 1630 nm) and the bandpass at -3 dB.<p/> Also with Photintech, Québec, Canada.