Hello, everyone.
In the last discussion, we discussed the causes of bit errors. Now, I've dedicated myself to question collection. I believe it's helpful for you!
Part I. The concept of bit errors
In both parties of optical communication, the party that transmits the signal assumes that 1010 is sent, but the receiving party receives 1011. Compared with 1010 and 1011, the last digit changes from 0 to 1. Therefore, the last digit 1 is an incorrect digit (should have been 0), that is the bit error.
Bit errors occur because the decay changes the voltage of the signal during signal transmission, which causes the signal to be damaged during transmission and generates bit errors. Noise, pulses from alternating current or lightning, transmission equipment failures, and other factors can cause bit errors. Due to various reasons, this kind of error will inevitably occur in the process of digital signal transmission.
In our lives, we can directly feel the impact of bit errors when making audio or video calls, because the channel quality deteriorates, there is noise in the speaker, and the other person is speaking intermittently. In addition, frame freezing or mosaic occurs in the video image.
Part 2. The causes of bit errors in the transmission network
1. The dispersion compensation is improper.
If the dispersion compensation is insufficient or excessively large, line bit errors occur.
NG WDM product dispersion compensation.
2. The optical power of the incident fiber is too high or too low.
In the commissioning project, the optical power design and planning are improper. For example, long-distance optical modules are not used when adjacent sites are far away, or the gain of the OA board is insufficient. Alternatively, the optical attenuator is not used when adjacent sites are close to each other.
3. Hardware performance reasons.
Mainly including subracks, boards, optical modules, and electrical modules. The causes of hardware performance deterioration are as follows:
Impact of hardware defects on signals. The device is nearing its service life，the hardware is faulty, the board software runs abnormally, and conductive foreign objects (such as dust) are accumulated on the board.
4. The physical connection is loose.
The connector of the signal cable is loose or seriously contaminated. The board is not securely installed, and the equipment is not securely grounded.
5. Optical cable attenuation changes.
The splicing quality of the optical cable is poor. The optical cable connector is soaked and corroded by water for a long time. The bending radius of the optical cable or pigtail is too small. The optical cable or pigtail is strongly squeezed and bound.
6. Hardware and cables do not match.
For example, an optical module that supports 1310 nm is connected to a G.655 fiber. An EDFA amplifier is used for the 1310 nm optical signal. Bit errors may occur in either of the preceding situations.
7. The working environment of the device is abnormal.
The temperature and humidity of the equipment are too high, the equipment has strongly interfered, or corrosive gases exist in the equipment room.
Case: The OSN2500 board is faulty due to the SO2 gas
8. Improper device parameter settings.
For example, the FEC function is disabled or the FEC modes at both ends of the link are inconsistent，excessive use of OA boards leads to a decrease in the OSNR value. Incorrect network clock settings lead to network clock disorder.
Extended information:
How to handle the Bit Error in MSTP network
How to handle the Bit Error in WDM Network
OTN _ Single-wave channel error code
That's all, I welcome everyone to leave a message and exchange in the comment area!
Thank you！
