Optical Modulator Phase Adjustment Circuit Timing Alignment

The patent applies preliminary action by delaying the drive signal for the second modulation area in advance to compensate for the light propagation delay. The delay amount is set to match the light propagation delay time through the first modulation area, ensuring that both modulation areas receive their respective drive signals at properly synchronized timings. This pre-compensation approach eliminates waveform distortion while maintaining high-speed data transmission capability.

The patent extracts the delay function from the amplifier and transmission line chain by implementing a dedicated delay circuit that provides precise timing adjustment without the bandwidth limitations of conventional signal paths. The delay circuit is designed to provide only the necessary delay amount (matching light propagation delay) without introducing additional signal degradation, thus maintaining signal integrity while achieving accurate timing alignment.

The patent applies local quality by providing different delay amounts to different modulation areas based on their specific requirements. The second modulation area receives a delay signal calibrated to compensate for its longer light propagation path, while the first modulation area receives no additional delay. This localized compensation approach allows each modulation area to operate optimally regardless of its length, enabling PAM4 capability while maintaining timing synchronization.