There are two ways to measure the Output power (TX power) and the receiver sensitivity (RX sensitivity) of SFP transceivers. DDM is short for Digital Diagnostic Monitoring, which provides users with critical information concerning the status of the transmitted and received signals. This includes key parameters like temperature, supply voltage, laser bias. Digital Diagnostics Monitoring (DDM), also known as Digital Optical Monitoring (DOM) or Diagnostic Monitoring Interface (DMI), is a standardized feature defined by SFF-8472 that allows network devices to monitor real-time optical transceiver parameters such as temperature, voltage, transmit power. The introduction of Digital Diagnostic Monitoring (DDM), often referred to as Digital Optical Monitoring (DOM), fundamentally transformed this paradigm, converting the passive transceiver into an intelligent, active network component. Built into modern SFP/SFP+/ SFP28 /QSFP family modules and standardized by SFF-8472, DDM/DOM exposes real-time values for the module's temperature, supply. The optical module serves as a crucial component in optical fiber communication systems, operating at the physical layer, which is the lowest layer in the OSI model. Its primary function is to achieve optoelectronic conversion by converting electrical signals into optical signals and vice versa.
