DDM in optical modules

With the increasing widespread use of optical modules, the rate, packaging, power consumption, and functionality of optical modules are also moving towards high speed, small size, low power and multi-function. Today we are going to discuss the DDM function in optical modules.

What is DDM?

DDM (Digital Diagnostic Monitoring) is a technology applied in optical modules that allows users to monitor the real-time parameters of the optical module. These parameters include operating temperature, operating voltage, operating current, transmit and receive optical power, etc. It also displays information such as the module's regular wavelength, rate, transmission distance, vendor name, field number, model number, serial number, field date and alarm information. Among commonly used optical modules today, the only one without DDM information is the electrical port module.

DDM technology in optical modules provides a means of monitoring module performance that can help manage predicting module lifetime, locating system faults, and detecting module compatibility.

How can I view DDM information?

Using a serial cable with an RJ45 connector on one end and a USB connector on the other end, connect the USB connector to the computer side and the RJ45 connector to the console of the switch. Open the terminal and enter the appropriate device command to view the DDM information of the optical module.

What is the role of digital diagnostic monitoring technology?

①Fault location

In optical service operation, faults are inevitable, and DDM technology can help network managers locate faults quickly, thereby reducing troubleshooting and repair time. With the digital diagnostic function, a comprehensive analysis of the warning status of transmit optical power, receive optical power, current, voltage and temperature is needed to quickly identify and resolve the problem.

②Compatibility test

Digital diagnostics can also verify the compatibility of the module. Compatibility verification involves analyzing whether the module's operating environment is compatible with the datasheet or with the relevant standards. The performance of the module can only be guaranteed in this compatible operating environment. In some cases, the module performance will be degraded due to environmental parameters that exceed the data manual or the related standards, resulting in the generation of transmission error codes.

The working environment is incompatible with the module in the following cases.

Voltage exceeding the specified range;

Excessively high or low receive optical power;

Temperature exceeding the operating temperature range.