An optimal AOWC based on XGM in dual WTWSOAs with co- and counter-propagation schemes for NRZ, RZ, CSRZ and Duobinary signals

In this article, we propose and demonstrate an optimal approach of all-optical wavelength conversion (AOWC) based on cross gain modulation (XGM) exploiting dual wideband travelling wave semiconductor optical amplifier (WTWSOA) for both counter- and co-propagating schemes. In counter propagating scheme, dual SOAs are in feedback loop whereas in co-propagating scheme dual SOAs are cascaded employing amplified synchronous emission (ASE) noise source. Input data signal of 193.4 THz is optically modulated employing different transmitters such as NRZ, RZ, CSRZ and Duobinary, for conversion at 128 Gbps. Good performance is achieved for ultrawideband wavelength conversion using both propagating schemes. The system performance is analyzed using carrier density curve as a function of distance in WTWSOA, bit error rate (BER), quality factor (Q) and extinction ratio (ER) of the eye diagram. Maximum Q factor of 14.06 at minimum BER of 2.38 × 10 −45 is obtained for counter-propagating scheme using NRZ optical transmitter at -5 dBm input signal power. Maximum Q factor of 17.84 at minimum BER of 1 × 10 −71 is obtained for co-propagating scheme using CSRZ optical transmitter at 0 dBm input signal power. Power penalty free wavelength conversion is realized due to high ER (> 15 dB) at optimized input conditions.