Design And Implementation Of Auto-test System For SFP Optical Modoule

With the rapid development of Internet in the 21 st century, so many optical access network applications like fiber to the home(FTTH, fiber to the home),fiber to the building(FTTB, fiber to The building) and fiber to the curb(FTTC, fiber to the curb) come to appear. SFP(Small Form-factor Pluggable) optical modules are a very important part of the modern fiber-optic communication networks. So the three biggest Telecommunication Corporations of China which are China Mobile, China Unicom, China Telecom have gradually increased the demand of SFP optical modules. SFP optical modules tend to be more intelligent, miniaturized and stability step by step.It also have the feature of low power consumption and long transmission distance in the same time.The demand of(155M, 1.25 Gps, 2.5Gps) SFP optical module in the Ethernet switches is growing faster and faster than before.Recently,the problem of producing the acceptable quality SFP optical modules massively and rapidly has becoming the most important one. More and more companies are competing to resolve this issue.This paper has a deeply research on the SFP optical modules. Combining with the existed hardware resources, the paper need to design an automatic test system for SFP optical modules which can cover the rate at 155 Mbps, 1.25 Gbps and 2.5Gbps. The main work is as follows: proposing the overall program of automatic test system based on SFF-8472 agreement, the transmitter and receiver test features; designing many methods of communication like connecting the SFP optical modules to computer by parallel port or USB, connecting the SFP optical modules to BERT by USB, connecting the oscilloscope to computer by GPIB interface and connecting the Optical Power Meter to computer by Serial port; building SQL SEVER2005 database server which could read the test indicators, save the test data recording and access database by the technology of ADO.NET;debugging the optical power, extinction ratio and alarm values with the method of improved binary search quickly; calibrating DDM data externally based on least squares;constructing a friendly and interactive interface on the programming platform of Net Framework 2.0.At last, the paper tests the entire test system according to the overall design requires.The test results show that the automatic test systems for SFP optical modules have a simple operation and a friendly interface. It can calibrate the monitoring data of digital diagnostic functions effectively and automatically. The error is very small between the automatic test system and manual test system. What's more, the automatic test system can detect those bad SFP optical modules effectively. It needs 60 seconds to test an SFP optical module(the launching part need 13 seconds, the receiving part need 15 seconds, the final part needs 16 seconds). The automatic test system reduces the test time significantly comparing to the manual test system.