The NRZ transmitter module consists of InP Mach Zehnder Modulator and conventional Distributed Feed-Back (DFB) laser. PAM4 vs NRZ, are the two most commonly used modulation technologies, each with its own advantages and applications. This article will delve into the differences between these two technologies, and their respective application scenarios, and guide how to choose the most suitable 50G optical module. PAM-4 acceptable for long links, but NRZ modulation preferred for short, latency sensitive links At 50Gb/s channel speed, Wavelength Division Multiplexing is essential for module scaling Wafer-scale 3-D packaging and assembly. Checking transceiver specification, NRZ or PAM4 are the common values for modulation. Enter Non-Return-to-Zero (NRZ), a cornerstone modulation scheme that has powered decades of data transmission, particularly within the critical realm of optical transceiver technology. While newer, more complex schemes emerge to handle escalating bandwidth demands, NRZ remains remarkably relevant. Two prominent modulation schemes, PAM4 (Pulse Amplitude Modulation 4-level) and NRZ (Non-Return-to-Zero), are often at the center of this discussion. But which one is more advantageous for 50G transceivers? Let's dive into the details.