Consideration based on simulation for a DWDM system composed of a wide‐band optical phase conjugator and dispersion‐flattened transmission line

Abstract

SUMMARYIn wavelength division multiplexing transmission, nonlinear effects such as cross phase modulation between the pulses of channels with different wavelengths due to overtaking causes pulse distortion and timing jitter. In particular, deterioration of the transmission characteristics caused by cross phase modulation becomes more conspicuous when the incident peak power becomes larger. In order to realize a wavelength division multiplexing transmission system with a higher bit rate over a longer distance, a high incident peak power that maintains a high SNR is indispensable and a technique to compensate the effect of cross phase modulation is needed. In this paper, computer simulation demonstrates that, by placing a broadband phase conjugator at the center of the dispersion-flattened transmission line, the cross phase modulations caused in the first half and the latter half are canceled and its effect can be reduced. It is further shown that the transmission system with the present configuration can increase the incident peak power by 5 dB over that using nonlinear transmission, which is considered effective for high densities in the case of wavelength division multiplexing transmission with a frequency use efficiency of 0.32 bit/s/Hz.