What test procedures are required for high-quality optical modules? Optical modules will go through strict testing and quality inspection procedures before shipment, such as material testing, parameter testing, aging testing, real machine testing, end-face testing, etc. This article provides a comprehensive guide on measuring key performance indicators to evaluate the functionality of optical modules, with a specific focus on the sfp28 transceivers. Optical crystal on the PCI test bench for measuring the residual absorption. »Spotlessly clean«: This also applies to components for high-power lasers.