The Role of DDM in Optical Module
2019-09-25
What is DDM?
DDM, namely digital diagnostic monitoring, is a technology used in SFP optical module so that users can monitor the real-time parameters of SFP. These parameters include optical output power, optical input power, temperature, laser bias current and power supply voltage of transceiver. DDM interface is a serial ID interface defined in GBIC specification and an extension of SFP MSA.DDM interface can also enable end users to isolate and predict faults. A DDM optical transceiver can help ensure that services can actively prevent network maintenance and ensure business continuity.
What is DOM?
DOM, short for Digital Optical Monitoring, is also a function that allows you to monitor all aspects of optical module data in real time, such as optical module transmission and reception, input and output power, temperature and voltage. Network administrators ensure that optical modules work properly by looking at these data. Obviously, SFP optical modules with DDM/DOM functions are better than those without these functions, so most SFP optical modules conform to SFF-8472 standard and can support DDM/DOM functions.
What is RGD?
RGD means a solid optical module, so the optical module with RGD function is an enhanced optical module, which is more durable and can be used in very harsh conditions. The rugged optical module has enhanced anti-static protection and a wider range of operating temperatures, thus eliminating site failures without expensive external protection equipment. It should be noted that the rugged SFP optical module can be identified by its product model, and the specific situation of RGD depends on the specific supplier.
Characteristics of optical transceiver module with DDM function
The optical transceiver module with DDM function not only has the characteristics of miniaturization, modularization and low cost of the traditional optical transceiver module, but also has the outstanding advantage of intellectualization. Its intellectualization is mainly manifested in the following aspects:
1) The digital potentiometer replaces the traditional regulator electronics and accesses and reads and writes through the second power C-line of serial data bus I.
2) Point erasable programmable read-only memory (PDROM) space consists of two space annotations: one is used to store fixed information and the other is mainly used to store information related to DDM monitoring function.
3) The module has monitoring function. It can monitor and report temperature in real time, supply voltage, bias current, transmit power and receive power.
4) Mikuai has diagnostic function. The module monitors whether the five reporting parameters of the module to be tested are within the normal range through the corresponding interface.
Digital diagnostic function
1) Real-time measurement parameters - emission power Tx_power, receiving power Rx_power, temperature temp, working voltage Vcc, laser bias Laser Bias;
2) Alarm or alarm - Tx_faul, the alarm and alarm mark of LOS measurement parameters.
3) Control flags -- Tx_disable, Rate_select.
Application of Diagnosis Functions.
Fault diagnosis function in optical transceiver module provides a means of performance monitoring for the system. It can help system management to predict the service life of transceiver module, isolate system faults and verify the compatibility of module in field installation.
Module Life Prediction
This fault prediction can enable network managers to find potential link failures before the performance of the system is affected. Through fault warning, system administrators can switch services to backup links or replace suspicious devices to repair the system without interrupting business.
Intelligent SFP provides a real-time parameter monitoring method for predicting laser degradation. The optical power feedback control unit inside the optical module will control the output power at a stable level. However, with the aging of the laser, the quantum efficiency of the laser will decrease. Power control is achieved by increasing laser bias current (Tx_Bias). Therefore, we can predict the lifetime of the laser by monitoring the bias current of the laser. This method can roughly estimate whether the lifetime of the laser is near the end. Because the bias current of the laser is related to the working temperature and voltage of the module, the influence of Temp and Vcc should be considered when setting the bias current limit. Through real-time monitoring of the working voltage and temperature in the transceiver module, system administrators can find some potential problems:
1) Vcc voltage is too high, which will bring breakdown of CMOS devices; Vcc voltage is too low, the laser cannot work properly.
2) If the receiving power is too high, the receiving module will be damaged.
3) If the working temperature is too high, the aging of the device will be accelerated. In addition, the performance of the line and the remote transmitter can be monitored by monitoring the received optical power. In optical links, locating the location of the fault is very important for fast loading of services. The fault isolation feature enables system administrators to locate link failures quickly. This feature can locate whether the fault is in the module or on the line; whether it is in the local module or in the remote module. By locating the fault quickly, the repair time of the system is reduced. In fault location, state positions, pin and measurement parameters need to be comprehensively analyzed.In short, through the digital diagnosis function, the fault can be located. In fault location, the warning and alarm status of Tx_power, Rx_power, Temp, Vcc and Tx_Bias need to be comprehensively analyzed. The state variables Tx Fault and Rx LOS (signal loss) in memory mirror play an important role in fault analysis.
Compatibility verification
Another function of digital diagnosis is module compatibility verification. Compatibility verification is to analyze whether the working environment of the module is compatible with the data manual or relevant standards. The performance of modules can only be guaranteed in such a compatible working environment. In some cases, because the environmental parameters exceed the data manual or related standards, the module performance will be degraded, resulting in transmission error. The incompatibility between working environment and module is as follows:
1) Voltage beyond the prescribed range;
2) The received optical power is overloaded or lower than the sensitivity of the receiver.
3) The temperature is beyond the working temperature range.
DDM, namely digital diagnostic monitoring, is a technology used in SFP optical module so that users can monitor the real-time parameters of SFP. These parameters include optical output power, optical input power, temperature, laser bias current and power supply voltage of transceiver. DDM interface is a serial ID interface defined in GBIC specification and an extension of SFP MSA.DDM interface can also enable end users to isolate and predict faults. A DDM optical transceiver can help ensure that services can actively prevent network maintenance and ensure business continuity.
What is DOM?
DOM, short for Digital Optical Monitoring, is also a function that allows you to monitor all aspects of optical module data in real time, such as optical module transmission and reception, input and output power, temperature and voltage. Network administrators ensure that optical modules work properly by looking at these data. Obviously, SFP optical modules with DDM/DOM functions are better than those without these functions, so most SFP optical modules conform to SFF-8472 standard and can support DDM/DOM functions.
What is RGD?
RGD means a solid optical module, so the optical module with RGD function is an enhanced optical module, which is more durable and can be used in very harsh conditions. The rugged optical module has enhanced anti-static protection and a wider range of operating temperatures, thus eliminating site failures without expensive external protection equipment. It should be noted that the rugged SFP optical module can be identified by its product model, and the specific situation of RGD depends on the specific supplier.
Characteristics of optical transceiver module with DDM function
The optical transceiver module with DDM function not only has the characteristics of miniaturization, modularization and low cost of the traditional optical transceiver module, but also has the outstanding advantage of intellectualization. Its intellectualization is mainly manifested in the following aspects:
1) The digital potentiometer replaces the traditional regulator electronics and accesses and reads and writes through the second power C-line of serial data bus I.
2) Point erasable programmable read-only memory (PDROM) space consists of two space annotations: one is used to store fixed information and the other is mainly used to store information related to DDM monitoring function.
3) The module has monitoring function. It can monitor and report temperature in real time, supply voltage, bias current, transmit power and receive power.
4) Mikuai has diagnostic function. The module monitors whether the five reporting parameters of the module to be tested are within the normal range through the corresponding interface.
Digital diagnostic function
1) Real-time measurement parameters - emission power Tx_power, receiving power Rx_power, temperature temp, working voltage Vcc, laser bias Laser Bias;
2) Alarm or alarm - Tx_faul, the alarm and alarm mark of LOS measurement parameters.
3) Control flags -- Tx_disable, Rate_select.
Application of Diagnosis Functions.
Fault diagnosis function in optical transceiver module provides a means of performance monitoring for the system. It can help system management to predict the service life of transceiver module, isolate system faults and verify the compatibility of module in field installation.
Module Life Prediction
This fault prediction can enable network managers to find potential link failures before the performance of the system is affected. Through fault warning, system administrators can switch services to backup links or replace suspicious devices to repair the system without interrupting business.
Intelligent SFP provides a real-time parameter monitoring method for predicting laser degradation. The optical power feedback control unit inside the optical module will control the output power at a stable level. However, with the aging of the laser, the quantum efficiency of the laser will decrease. Power control is achieved by increasing laser bias current (Tx_Bias). Therefore, we can predict the lifetime of the laser by monitoring the bias current of the laser. This method can roughly estimate whether the lifetime of the laser is near the end. Because the bias current of the laser is related to the working temperature and voltage of the module, the influence of Temp and Vcc should be considered when setting the bias current limit. Through real-time monitoring of the working voltage and temperature in the transceiver module, system administrators can find some potential problems:
1) Vcc voltage is too high, which will bring breakdown of CMOS devices; Vcc voltage is too low, the laser cannot work properly.
2) If the receiving power is too high, the receiving module will be damaged.
3) If the working temperature is too high, the aging of the device will be accelerated. In addition, the performance of the line and the remote transmitter can be monitored by monitoring the received optical power. In optical links, locating the location of the fault is very important for fast loading of services. The fault isolation feature enables system administrators to locate link failures quickly. This feature can locate whether the fault is in the module or on the line; whether it is in the local module or in the remote module. By locating the fault quickly, the repair time of the system is reduced. In fault location, state positions, pin and measurement parameters need to be comprehensively analyzed.In short, through the digital diagnosis function, the fault can be located. In fault location, the warning and alarm status of Tx_power, Rx_power, Temp, Vcc and Tx_Bias need to be comprehensively analyzed. The state variables Tx Fault and Rx LOS (signal loss) in memory mirror play an important role in fault analysis.
Compatibility verification
Another function of digital diagnosis is module compatibility verification. Compatibility verification is to analyze whether the working environment of the module is compatible with the data manual or relevant standards. The performance of modules can only be guaranteed in such a compatible working environment. In some cases, because the environmental parameters exceed the data manual or related standards, the module performance will be degraded, resulting in transmission error. The incompatibility between working environment and module is as follows:
1) Voltage beyond the prescribed range;
2) The received optical power is overloaded or lower than the sensitivity of the receiver.
3) The temperature is beyond the working temperature range.
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