Over the past seven years the optical transport industry has made huge strides in increasing the capacity of a single fiber using the C-band. The combination of higher order modulation, flex grid channel spacing, higher symbol rates and super channels has increased the spectral efficiency to deliver 32 Tbit/s per single fiber using the standard C-band or 38.4 Tbit/s in systems supporting the extended C-band. By developing a new optical amplifier and other system enhancements, Huawei has taken this process one stage further to support 48 Tbit/s per single fiber using a Super C-band (Super C). This innovative solution can deliver up to an additional 50% capacity without the need for parallel L-band optics.
Cloud services and massive increases in broadband capacity for businesses and residential users, over both fixed and mobile networks, are driving demand for higher-bandwidth transport networks between users and data centers, and between data centers. There are several key technology approaches to increasing the capacity of a single C-band fiber link including higher symbol rates, more bits per symbol, greater spectral efficiency, and more flexible line rates and channel spacing. Much has already been achieved and many of these approaches are reaching the limits that can be achieved with current technology. Other alternatives to increasing capacity include using additional spectrum by adding L-band optics (C + L), or by adding many more fibers, both of which requires multiple line systems and can be expensive.