A silicon-based optical modulator is configured as a multi-segment device that utilizes a modified electrical data input signal format to address phase modulation nonlinearity and attenuation problems associated with free-carrier dispersion-based modulation. The modulator is formed to include M separate segments and a digital signal encoder is utilized to convert an N bit input data signal into a plurality of M drive signals for the M modulator segments, where M≧2N/2. The lengths of the modulator segments may also be adjusted to address the nonlinearity and attenuation problems. Additional phase adjustments may be utilized at the output of the modulator (beyond the combining waveguide).