Improved NRZ transmission distance at 20 Gb/s using a Dual Electro-absorption Modulated Laser

The deployment of today's access and metropolitan networks requires the development of extremely high-speed, low cost and low consumption optical sources. For OOK signals, the reduction of the spectral content into one side band can be obtained by respecting Binder and Kohn's condition between the frequency (FM) and amplitude (AM) modulation for single lasers [1]. In fact, this condition acts on the peak-to-peak (pp) adiabatic chirp allowing a spectrum sculpting for dealing with fiber dispersion. The optical frequency difference between marks and space symbols is given by: fpp = m(B/2) where m is the intensity modulation index and B is the signal bit rate. For a large extinction ratio this comes to inducing a -phase shift between two marks separated by a space and vice versa. Therefore, space symbols are better separated producing