What are the common problems in using optical modules?
After some data analysis and collection, the common problems of optical module are as follows.
1. Compatibility problems (which are the most basic and common ones) are caused by the following aspects:
a. Errors occurred in the process of importing compatible codes;
b. The software update of the device results in the failure of the original compatible code which has not been upgraded;
c. Coding error;
2. There are several reasons for this situation:
a. The electronic function circuit of optical module and equipment does not match;
b. The main chip does not match with the device;
c. Physical circuit failure;
d. Equipment failure;
e. The route information is wrong;
3. The pollution and damage of optical port. The pollution and damage of optical interface will cause the loss of optical link to increase, which will lead to the failure of optical link. The reasons for this situation are as follows:
a. The optical port of the optical module is exposed to the environment, and the light port is polluted by dust;
b. The end face of the optical fiber connector used has been polluted, and the optical port of the optical module is secondary polluted;
c. The end face of optical joint with pigtail is not used properly and the end surface is scratched;
d. Use poor quality optical fiber connector;
4. ESD damage, static electricity will absorb dust, change the impedance between lines, and affect the function and life of the product. The possible factors causing ESD damage include:
a. The environment is dry and easy to produce ESD;
b. Abnormal operation, such as: live operation of non hot swap optical module; direct contact with electrostatic sensitive pin of optical module by hand without electrostatic protection; no anti-static packaging during transportation and storage;
c. The equipment is not grounded or poorly grounded;
Problems and Solutions
Problem 1: after the two optical modules are interconnected, the light port light is not on
Reasons: 1. The parameters of optical modules at both ends do not match, such as wavelength, speed and transmission distance.
2. The type of optical fiber jumper used does not match the optical module.
3. The optical module is not compatible with the switch brand
Solution: first check whether the optical port is open, and then check whether the parameters of optical modules (such as wavelength, speed and transmission distance) inserted by devices at both ends match, and whether the optical module type (single-mode / multi-mode) matches the jumper type, and then check whether the gateway is configured and whether the VLAN is consistent.
The single-mode optical module needs to be connected with single-mode OS2 jumper, and the multi-mode optical module needs to be connected with multi-mode jumper such as OM3 / om2. If the switch brand is not compatible with the optical module, the optical module compatible with the switch brand shall be replaced.
Problem 2: the indicator light of a-end optical module is on, and that of b-end optical module is not on
Troubleshooting and solutions: if the optical fiber jumper corresponding to the receiving port of the optical module is normal, the problem lies in the optical fiber jumper at the transmitting port; if the indicator light of the optical module at a end is on, but the indicator light of the optical module at the B end is not on. The solution is to change the position of the optical fiber jumpers at both ends. If the light module indicator at the B end is on and the optical module indicator at the a end is not on, it indicates that one of the optical fiber jumpers has a problem. If the a-end optical module can receive the optical signal from the b-end optical module, but the b-end optical module cannot receive the optical signal of the a-end optical module, it is certain that there is a problem with the optical module or jumper at the a end.
Problem 3: after inserting the optical module, the switch indicator light is red
Reasons and solutions: the main reason is that the optical module is not compatible. You can open the operation data and check the manufacturer information of the optical module. If you find that it is incompatible with the switch brand, you can directly replace the optical module.
Problem 4: the interface alarm message appears after the optical module is inserted
Solution: you can check whether the working parameters, interface information and reception of the optical module are normal, and then check the optical fiber jumper, or try to replace the optical fiber jumper and the optical module. After the optical module is replaced, you need to observe the status of the alarm light.
Problem 5: ism monitors the optical module fault alarm, and the port corresponding to the optical module is on red light
Problem 6: the loss of the optical link increases / the optical link is not working
Reasons: 1. The optical port of the optical module is exposed to the environment, and the light port is polluted by dust;
2. The end face of the optical fiber connector used has been polluted, and the optical port of the optical module is secondary polluted;
3. Improper use of the end face of optical joint with pigtail and scratches on the end face;
4. The quality of optical fiber connector is too poor.
Solution: if the optical port of the optical module is polluted, it is necessary to dip some alcohol into the optical port with a cotton stick to clean the port; if the end face of the optical fiber connector is polluted, wipe the end face with Sassafras paper, and then insert it.
Problem7: electrostatic damage
Reasons: 1. The environment is dry and easy to generate static electricity, which will absorb dust, change the impedance between lines and affect the function and life of optical module;
2. Abnormal operation, such as live operation of non hot plug optical module; direct contact with electrostatic sensitive pin of optical module without electrostatic protection; no anti-static packaging during transportation and storage;
3. The equipment is not grounded or poorly grounded.
Prevention: wear anti-static gloves and anti-static shoes when contacting the light module.
By understanding the common problems of these optical modules, it is helpful for us to find out the causes of optical module failure, and help us to solve the problems in time. In addition to the operator's own experience, the problems in the use of optical modules are closely related to the quality and performance of optical modules, switches and optical fiber jumpers. If we use optical modules and related products with strong reliability and stable performance, we will greatly reduce the probability of optical module failure in the process of use. Yitian optical communication has a complete test system, a comprehensive product line, and all products are in line with international standards.
The method of judging the fault of optical module
1. Look at the appearance by visual inspection
The appearance of the light module is observed by visual inspection, and the surface of the module is checked for obvious damage traces. Then, the components are checked for signs of cracking, missing paste, tin connection or even burning black.
2. Comparison method to measure parameters to see the difference
If the visual inspection method looks good, you can use the relevant detection instrument to detect a new module and the module that may have a fault, and it can be divided into two situations: power on and power off. Check the voltage, resistance and waveform of circuit parts or components, and then compare the test results of new module and bad module to determine the problem.
3. Replacement method to replace components to see parameter changes
If it is found that there are differences in the introduction of test parameters, the corresponding components or components of the module that may be faulty can be replaced with good product components or components of the same model, and then test the parameters again to see whether they return to normal.
4. Determine the faulty circuit area according to some bad condition
According to some bad conditions, determine the fault circuit area, such as: poor optical power, mainly check the transmitting area, poor sensitivity, check the receiving area, etc., which can reduce the maintenance time and improve the efficiency.
5. Through the structure of the hanging light module, the components of the fault can be judged
We all know that the optical module is mainly composed of Tosa module, Rosa component and PCBA board. If you want to judge the components of fault, there are several methods to judge:
① Remove Tosa and Rosa components, and test their performance on the component test board.
② When the power is on, use a multimeter to measure the voltage of each pin to see whether the voltage value is normal; when the power is off, use the multimeter to test whether the circuit led out by the heel pin of the pin is connected.
③ According to the bad condition, test the corresponding parameters to see the change of the parameters. For example, if the bad reason is "low optical power", then the power of the module can be tested. If the power is increased, the reading of the power meter will increase, and the bias value of the bias current will also increase, and the working current will increase. This change shows that the PCBA circuit is on, and the drive performance and storage performance are no problem. It can be preliminarily judged that the optical power of Tosa is poor and the PCBA board is good, but it does not rule out the possibility of poor PCBA.
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