A novel digital post compensation scheme for third-order intermodulation distortion suppression in intensity modulated analog optical links is proposed and experimentally demonstrated. In this scheme, nonlinear compensation function to linearize the overall transfer characteristic of analog optical link with electro absorption modulator is dynamically obtained according to the actual situation. Thus third-order intermodulation distortion terms produced by digital signal processing (DSP) unit are approximately equal amplitude and opposite phase relative to IMD3 components generated in the modulator. The two IMD3 signals are added destructively and 24dB suppression in IMD3 is achieved in the experiment. Subsequently an improvement in spur-free dynamic range (SFDR) is realized.
© 2011 Optical Society of AmericaPDF Article