Optical EngineeringSimulation of vestigial side-band-modulation optical transmission: performance and some aspects of electronic equalization
|Format||Member Price||Non-Member Price|
This paper demonstrates via simulation, the transmission of multiwavelength channels using vestigial single-side-band (VSB) modulation at 40 Gb/s bit rate over long-haul optically amplified fiber systems. Bit-error-rate (BER) of 10-12 or better can be achieved across all channels. The principal component, the optical filter, for eliminating one of the signal side bands is designed with asymmetric roll-off bands in order to relax the demands on the high order of the optical filtering system and hence increase ease of implementation in the photonic domain. Simulations of the transmission performance, BER versus receiver sensitivity and dispersion tolerance are demonstrated with wavelength channel spacing of 20–40 GHz. An optical filter, pass band of 28 GHz and a 20 dB cutoff band performs best for 40 Gb/s return-to-zero VSB due to optimum filtering and minimum noise contribution. Furthermore, the single side-band property of VSB format facilitates linear equalization by electronic processing. Two typical equalization schemes using linear and nonlinear equalizers are reported.