Reduction of nonlinear distortion from a semiconductor optical amplifier using an optical equalizer

We demonstrate significant improvement in the measured bit-error rates of 40-Gb/s signals distorted after passing through a saturated semiconductor optical amplifier (SOA) by using a simple colorless general optical equalizer. The optical equalizer reduces the overshoots arising from the nonlinear gain dynamics of the SOA and improves the opening of the eye. We study the improvement in receiver sensitivity by using the equalizer while varying the optical power and wavelength at the input of the SOA.