Long, low loss etched As2S3 chalcogenide waveguides for all-optical signal regeneration

We report on the fabrication and optical properties of etched highly nonlinear As2S3 chalcogenide planar rib waveguides with lengths up to 22.5 cm and optical losses as low as 0.05 dB/cm at 1550 nm - the lowest ever reported. We demonstrate strong spectral broadening of 1.2 ps pulses, in good agreement with simulations, and find that the ratio of nonlinearity and dispersion linearizes the pulse chirp, reducing the spectral oscillations caused by self- phase modulation alone. When combined with a spectrally offset band-pass filter, this gives rise to a nonlinear transfer function suitable for all- optical regeneration of high data rate signals. (C) 2007 Optical Society of America.