Optical signal processing is a promising technique to enable fast data information processing in the optical domain. Traditional optical signal processing functions pay more attention to binary modulation formats (i.e., binary numbers) with single-bit information contained in one symbol. The ever-growing data traffic has propelled great success in high-speed optical signal transmission by using advanced multilevel modulation formats (i.e., high-base numbers), which encode multiple-bit information in one symbol with resultant enhanced transmission capacity and efficient spectrum usage. A valuable challenge would be to perform various optical signal processing functions for multilevel modulation formats, i.e., high-base optical signal processing. In this chapter, we review recent research works on high-base optical signal processing for multilevel modulation formats by exploiting degenerate and nondegenerate four-wave mixing in highly nonlinear fibers or silicon photonic devices. Grooming high-base optical signal processing functions including high-base wavelength conversion, high-base data exchange, high-base optical computing, and high-base optical coding/decoding are demonstrated. High-base optical signal processing may facilitate advanced data management and superior network performance.
Part of the book: Applications of Digital Signal Processing through Practical Approach