This work focuses on the use of signal processing, both digital and optical, for robust signal identification and adaptive impairment correction in coherent optical links. The objective of this research is multi-pronged. First, to develop and validate a blind architecture for the classification of practical coherent waveforms for 100G to 400G links, which requires the consideration of 64QAM formats, time-domain hybrid modulation formats, probabilistic shaping, and constellation shaping. Second, to develop and validate a blind architecture for OFDM waveforms transmitted over fiber-wireless links. Third, to demonstrate and investigate the utilization of hybrid fiber-wireless systems for high-bandwidth wireless transmission and low loss fiber remoting, using single- and multi-carrier modulation formats. Fourth, to develop and validate an optical cyclostationary processor using nonlinear optical signal processing to evaluate the spectral correlation function of wide bandwidth waveforms.Ph.D