SFP DOM (Digital Optical Monitoring), also known as DDM, is a standardized capability that allows an SFP or SFP+ optical transceiver to report internal operating parameters—such as optical power, temperature, voltage, and laser bias current—via a digital interface. All of these parameters can be monitored in real-time. Examples. That's why network administrators are turning to SFP DDM, a built-in diagnostic system that brings real-time transparency to optical transceiver modules.