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 177 GHz. The seed of the comb is combination of two narrow-linewidth semiconductor lasers which are locked to two absorption lines of the acetylene ((C2H2)-C-12). (c) 2008 Elsevier B.V. All rights reserved.