September 3rd, 2026
PAM4 Modulation Technology: Signal Integrity Analysis at High Bit Rates for 100G/400G/800G Optical Transceivers
PAM4 modulation is now the standard signaling scheme for high-speed optical transceivers at 100G, 400G, 800G. If you're specifying or deploying modern optics, understanding its signal integrity characteristics isn't optional—it's foundational. This article covers what PAM4 is, why it displaced NRZ at higher data rates, the specific signal integrity challenges it introduces, and how DSP-based equalization combined with forward error correction keeps those challenges under control in real networks