Optical amplitude multiplexing through four-wave mixing in optical fibers

We propose a new optical amplitude multiplexing technique that consists of merging two wavelength multiplexed on-off keying (OOK) signals into a single quaternary amplitude shift keying signal. This technique is based on four-wave mixing in a single-mode optical fiber and requires power offset from the OOK signals. Simulation results indicate that the multiplexing may be performed between signals of the same or different bit rates. As a consequence, the proposed technique may be used not only for increasing spectral efficiency but also for optical labeling.