Long-period gratings in chalcogenide (As 2 S 3 ) rib waveguides

Long-period gratings in highly nonlinear chalcogenide glass (As2S3) rib waveguides are fabricated. A strong resonance of ∼17 dB depths and 3 dB width of ∼15 nm is obtained at a wavelength of 1525 nm by coupling the fundamental mode to the HE02 mode in good agreement with theory. The 20 mm grating is produced by a simple shadow mask technique and has a pitch of Λ=80 µm.