The employment of higher-order modulation in terabit optical fiber transmission systems may be a way of increasing spectral efficiency and making better use of transmission capacity of currently existing fiber infrastructure. However, transmission signal quality and transmission channel impairments may become more critical for performance of higher-order modulation systems. Advances in high speed analog-to-digital converters (ADCs) and deep submicron semiconductor processing technologies in digital signal processors (DSPs) may enable advanced digital signal processing techniques to be applied for signal conditioning and/or distortion compensation at optical transmitters and/or receivers.