Coherent data system and slow data transmission in a single fiber with ITU grid spacing

In the period following the COVID-19 outbreak, there continues to be a demand for high-speed data services and sufficient bandwidth. From a transport network perspective, a coherent system transmits data independent of the specific transmission wavelengths . However, it is desirable to address the transmission of slow signals (e.g., OOK) in the same fiber and their interaction between transmissions. Here, we assess the effect of a slow signal with a low modulation rate in a DWDM network on high-speed (super channel) 800G transmission. To evaluate the effect on high-speed transmission, the Q factor and ESNR parameters provided by the Ciena transmission system were analyzed. For the test setup and the combination of the coherent 800G signal with the standard DFB transceiver signal and 100 GHz spacing. The 800G signal required 112 GHz bandwidth for its transmission. For a path length of 200 km and for modulation rates of the OOK signal ranging from 100 Mbit to 4 Gbit, we found no significant effect on the evaluated parameters of the Q factor and ESNR of the transmitted 800 G signal. The more significant effect on the 800G signal is, the mutual power level of neighboring channels with different modulation types. To limit the mutual influence of adjacent signals, these signals must also be balanced according to their maximum (peak) power level in the transmitted spectrum.