Capacity Scaling Limits and New Advancements in Optical Transmission Systems

[Abstract] Optical transmission technologies have gone through several generations of development. Spectral efficiency has significantly improved, and industry has begun to search for an answer to a basic question: What are the fundamental linear and nonlinear signal channel limitations of the Shannon theory when there is no compensation in an optical fiber transmission system? Next-generation technologies should exceed the 100G transmission capability of coherent systems in order to approach the Shannon limit. Spectral efficiency first needs to be improved before overall transmission capability can be improved. The means to improve spectral efficiency include more complex modulation formats and channel encoding/decoding algorithms, prefiltering with multisymbol detection, optical OFDM and Nyquist WDM multicarrier technologies, and nonlinearity compensation. With further optimization, these technologies will most likely be incorporated into beyond-100G optical transport systems to meet bandwidth demand.

[Keywords] spectral efficiency; Shannon limit; Gaussian noise; optical signal noise ratio; modulation; nonlinearity compensation