Fabrication of Channel Waveguides in Chalcogenide Glass Films by a Focused Laser Beam
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We demonstrate a simple optical method for the fabrication of micrometer-width channel waveguides in chalcogenide glass (ChG) films, which does not require lift-off lithography. The method is based on photo-induced mass transport. For our experiments we use 400–600-nm-thick amorphous films of As2S3 and As10Se90 deposited in vacuum onto glass substrates. The waveguides are fabricated by a focused Ar ion laser beam (λ = 514 nm) with a waist diameter of ~0.7 μm. The positioning of the film in x-y-z-directions is controlled by computerized motor-driven stages whereby complex waveguide configurations can be drawn. For coupling of light (λ = 1.55 μm) between an optical fiber and the waveguide we used gratings, fabricated in the ChG, with a period of 0.8–1.5 μm and amplitude of 50–100 nm. The gratings are fabricated in an in-plane taper by laser illumination of the selected film area by two crossing p-polarized laser beams. We discuss mechanisms and kinetics of photo-induced mass transport in ChG films and possible contribution of viscous flow induced by a temperature gradient caused by the local heating of the film by the focused laser beam.
KeywordsChalcogenide Glass Channel Waveguide Grating Coupler Waveguide Fabrication Stage Speed
This work was supported by the Israel Science Foundation (Grant # 894/10).
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