Cascaded Mach-Zehnder Modulators for High-Fidelity Waveform Upscaling

The patent divides the signal processing into multiple stages, with the DAC operating at a lower speed to generate the base signal, and subsequent upconversion stages handling the high-frequency components. This segmentation allows each stage to operate within its optimal performance range, maintaining high SNR in the baseband while achieving high overall bandwidth through the multi-stage architecture.

The patent introduces an intermediate baseband signal as a mediator between the low-speed DAC output and the high-speed optical output. The baseband signal serves as an intermediary that can be processed with high precision by the DAC, then transformed to the final high-frequency signal through modulation, thereby preserving signal quality while achieving high bandwidth.

The patent segments the high-speed signal generation task into multiple lower-speed stages: a baseband DAC stage operating at lower speed, and subsequent upconversion modulation stages. This segmentation avoids the need for a single high-speed DAC, reducing manufacturing complexity while achieving the desired overall bandwidth through the coordinated operation of multiple simpler stages.

The patent replaces the mechanical/electronic approach of using a single high-speed DAC with an optical modulation approach. By using optical modulators to perform the upconversion function, the system achieves high bandwidth without requiring the DAC itself to operate at high speeds, thereby reducing the complexity and cost of the electronic components.