Generation of a reference frequency comb by cascaded four-wave mixing enhanced by Raman amplification

Abstract: The generation of standard reference frequencies close to the ITU channels is essential for the frequency calibration of DWDM systems. This paper describes the generation of a reference frequency comb based on the combination of a cascaded four-wave mixing in two semiconductor optical amplifiers and Raman amplification in a dispersion-shifted optical fiber. As a result we have achieved a stable frequency comb with 36 reference lines separated by a constant frequency spacing of 177GHz. The seed of the comb is combination of two narrow-linewidth semiconductor lasers which are locked to two absorption lines of the acetylene (12C2H2). [Copyright &y& Elsevier]