Patent attributes
An optical modulator is formed to include a plurality of separate electrodes disposed along one arm, the electrodes having different lengths and driven with different signals to provide for multi-level signaling (e.g., PAM-4 signaling). By using separate drivers to energize the different sections, the number of sections energized at a given point in time will define the net phase shift introduced to the optical signal. The total length of the combined modulator sections is associated with a π phase shift (180°). Each section is driven by either a digital “one” or “zero”, so as to create the multi-level modulation. An essentially equal change in power between adjacent transmitted symbols is accomplished by properly adjusting the lengths of each individual section.
