What is the Digital Diagnostic Monitoring feature of an Optical Transceiver?
Today, Fiber Optic Networks rely on optical transceivers to send the optical light down the optical cable. These optical transceivers come in many form-factors and types. They are modules that transmit and receive optical data using incorporated lasers.
When it comes to reliability of an optical network, regarding the maintenance and troubleshooting of the different fiber links, it is crucial for the engineers to know the current status of the optical cable and especially of the optical transceiver. For this reason, the various vendors started incorporating the Digital Diagnostic Monitoring (DDM) or Digital Optical Monitoring (DOM), feature in their optical transceivers.
The Digital Diagnostic Monitoring function is a tool for the engineers to monitor the status of the optical transceiver in real time. This is a standardized feature by the Multi-Source Agreement (MSA) SFF-8472. When purchasing an optical transceiver today, every actual form factor has this function. With this feature the engineer can monitor the various parameters of the optical transceiver like the temperature, power voltage, optical laser bias, TX (transmit) and RX (receive) power. Literally, this feature can provide even the tiniest details of the optical transceiver in real time without powering of or configuring the device. However, the Digital Diagnostic Monitoring feature has some more tricks in its sleeve. The feature also offers a complex system of programmed alarms and alerts which alert the host device when a particular parameter is beyond the default or preconfigured threshold. With this, DDM / DOM can allow the user to isolate the fault and predict failures much earlier and easier.
The Digital Diagnostic Monitoring feature can monitor the key parameters of the optical transceiver. Here again as an overview:
Temperature of the module
Supply voltage of the module
Laser bias current
Average transmit power of the module
Average receive power of the module
Usually the output of physical value of the parameters is an analog voltage or current coming from the Trans impedance amplifier, the optical laser or the post amplifier. Then with the help of microcontrollers, these digital values can be recorded in a register. These parameters are monitored to alert the host system when they are over the specified operating limit. With the feature for isolation of the fault, the engineer can easily locate the source of the issue in the Optical Network. Combining the results from the real time monitoring with the fault isolation feature, pinpointing the source of the issue is simple. The Digital Diagnostic Monitoring feature can also be used for fault prediction. This is done with the help of the transceiver's average results of the monitoring of the key parameters. There are two common issues that can be seen on an average optical transceiver:
A malfunction of the module - typically the issue comes with the transmitting part of the transceiver due to the nature of its semiconductor lasers
High error rate, high signal-to-noise limit, typically the issue stands with the receiving part of the transceiver
Providing key parameter statistics, real-time monitoring, fault detection and fault prediction will guarantee the business proactivity in maintenance and troubleshooting of possible network issues and ensure continuity and growth. That is why today the Digital Diagnostic Monitoring feature is very popular for the leading IT companies in the world. To satisfy the customer's needs for maintenance and diagnostic, all CBO Blueoptics© transceivers come with Digital Diagnostic Monitoring function.