In recent years, fiber optic communications network has achieved rapid development. Optical transceiver module as one of the key technologies of optical fiber communication network is widely used in a variety of optical communication systems. Smart SFP optical module, which uses digital diagnostic functions fiber optic sfp module, it can achieve real-time monitoring of network management unit transceiver module temperature, supply voltage, laser bias current, and optical power transmission and reception. The measurement of these parameters can help identify the location management unit fiber link failure occurs, simplify maintenance, improve system reliability. Optical modules to achieve real-time monitoring capabilities for effective life prediction module, isolation system failures, as well as to verify the correctness of the module status during the installation and commissioning of high practical value. The author based digital diagnostics, design and implement a monitoring platform of an optical module. The platform uses the microcontroller via a 2-wire serial bus to access the modules to read and deal with related parameters, while module parameters to be read in real time through the LCD display. And with CDR (clock data recovery) section, can signal clock recovery and data retiming, as a basis for hardware monitoring module in the relevant technical specifications designed monitoring platform. This post will introduce some knowledge on SFP digital diagnostics.
1.1 the basic principle of SFP digital diagnostics
In the SFF-8472MSA, the specification of the digital diagnostic functions and related SFF-8472 for details. The specification, in the northern part of the circuit board module detection and digital signal parameters. Then, provide calibrated results or provide digitized measurements and calibration parameters. This information is stored in standard memory results in order to read through the two-wire serial interface. Retained the original bidi sfp transceiver / GBIC Address Address A0h at the map and added a 256-byte storage unit at the address A2h SFF-8472 in the agreement. This information is stored in addition to providing parameters to detect, but also defines the alarm flag or alarm conditions, the state of the mirror each pin, limited number of control and user-writable storage unit.
1.2 The role of SFP digital diagnostics
(1)intelligent life prediction 10g sfp module provides a prediction methods of the parameters of the laser degradation of real-time monitoring.Light module within the light power feedback control unit will power output control at a stable level, power control is by increasing the laser Tx_Bias (offset current).Therefore, we can through the monitoring of the laser bias current can be used to predict the life of the laser.
(2) fault location In optical links, the location of the fault occurs is critical to business fast load positioning.Fault location, need comprehensive analysis of status, a pin and measuring parameters.Through to the detected Tx_power (sending power), Rx_power (received power), Temp (temperature), Vcc (voltage), Tx_Bias (offset current) warning and alarm status, Tx Fault image of the state variables (alarm) and RxLOS (receiving signal loss), and other information for comprehensive analysis, can locate the Fault is in the module or on the lines, in local module or in the remote module.
(3) compatibility verification by monitoring the voltage is outside the specified range, whether the received optical power overload or below the receiver sensitivity, temperature exceeds the operating temperature range, etc., work environment analysis module meets the data sheet or compatible with the relevant standard.