Introduction.- Single-carrier advanced modulation formats.- Basic Digital signal processing for single carrier signals.- Quasi-linear coherent optical transmission system and digital signal processing.- Super Nyquist wavelength division multiplexing system.- All-optical Nyquist signal.- Nonlinear compensation in optical fiber.- Probabilistic Shaping.- High baud signal transmission.- Advanced modulation code optical signal transmission technology.- Carrierless amplitude and phase modulation.- PAM 4 signal modulation and digital signal processing-based detection technology.- Optical OFDM.- Direct Detection OFDM.- Intensity Modulation Direct Detection High Speed Fiber Access System.- High-speed fiber access system based on direct detection of IQ modulation.- Forward Error Correction.- High Spectral Efficiency Optical Four-Dimensional Modulation.- Machine Learning Algorithm in the Optical Communication System.- Kramers-Kronig receiver in direct detection.