Simplified volterra series based nonlinear equalization in short reach optical transmissions

In this paper, theoretical investigation about the nonlinearity distortion caused by the chromatic dispersion and square law detection is presented. Then Volterra series based nonlinear equalizer (VNLE) is proposed for CAP modulation short reach optical transmission. The coefficients for high order Volterra kernels in the VNLE are investigated and the number of nonlinear memory length is optimized. More than 1 dB improvement at BER of 3.8 × 10
^-3
for 28 Gb/s CAP16 signal after 15km is observed with the help of the proposed simplified VNLE that only considering about the 2nd intra-kernels.