Flexible optical modulation technologies for data center applications

Communication equipment for data center applications needs to be low-cost, energy-efficient and flexible in the sense that spectral efficiency, reach and complexity should be adjustable with a high degree of flexibility in the digital signal processing of the transceivers. We present and compare different flexible modulation formats like discrete multi-tone, time domain hybrid pulse amplitude modulation and multidimensional modulation in the environment of data centers. We use vestigial sideband transmission to avoid power fading and minimize the influence of signal-signal-beating interference by optimization of the optical signal to carrier ratio.