Fiber optic cable water peak refers to the phenomenon of signal attenuation or loss in optical signal transmission caused by physical changes or damage between the fiber optic cable and the external environment in fiber optic communication. The water peak in optical cables may be caused by various reasons, one of which is the influence of water on optical fibers.
This water peak mainly appears in the E-band of the light spectrum, as the absorption of hydroxide ions (OH -) increases sharply in the 1370-1410nm band. This is also known as the water peak.
In the early days, due to process limitations, water (OH) impurities were often left in fiber glass, resulting in the highest attenuation in the E-band and inability to function properly. Later, dehydration technology was invented during the glass making process, and the attenuation of the most commonly used optical fiber in the E-band (ITU-T G.652. D) became lower than that in the O-band. However, due to the high attenuation exhibited by many existing fiber optic cables installed before 2000 in the E-band, there are still some limitations to the use of the E-band in optical communication.
And the optical fiber is usually wrapped in a protective layer, but if the protective layer is damaged or the cable is not properly sealed during installation, moisture may seep into the cable. When water enters the optical fiber, it can cause attenuation and scattering of the optical signal, thereby reducing the quality and transmission efficiency of the signal. Fiber optic cable water peak may lead to a decrease in signal strength, an increase in data transmission error rate, and a decrease in communication quality.
In order to avoid or reduce the impact of water peak on optical cables, measures such as regular inspection and maintenance of optical cables, ensuring the integrity of their protective layer, and paying attention to waterproof measures during installation and maintenance are usually required. Once the optical cable is affected by a water peak, it is usually necessary to detect and repair the damaged parts to ensure the normal transmission of optical signals.
Therefore, maintaining the integrity and proper maintenance of optical cables is crucial for ensuring the performance of optical communication systems.
FAQ
What are the factors causing fiber loss?
The main loss factors of optical fibers include absorption loss, Rayleigh scattering loss, and other losses. These losses can be classified into intrinsic losses, manufacturing losses, and additional losses.
Fiber manufacturing losses are generated during the manufacturing process of optical fibers, mainly caused by the absorption of impurities in the fiber (impurity absorption) and structural defects in the fiber. The significant impact of impurity absorption is the loss of light caused by various transition metal ions and OH – ions. The influence of OH – ions is relatively significant, with absorption peaks located at 950nm, 1240mm, and 1390nm, respectively, which have a significant impact on fiber optic communication systems. The loss peak caused by OH – ions is the water peak.
With the continuous improvement of fiber manufacturing technology, the influence of transition metals is no longer significant. The best process can reduce the loss of OH – ions at 1390nm to 0.04dB/km, even to a negligible level.
What is Zero Water Peak?
Zero Water Peak (ZWP) fiber eliminate the attenuation loss in the water peak spectrum, and further lowers the loss across the entire wavelength spectrum. There are 3 types of water peaks
- RWP stands for Reduced Water Peak
- LWP stands for Low Water Peak
- ZWP stands for Zero Water Peak
The ‘E band’ is the 1360-1460nm wavelength. The specific wavelength of 1383nm is referred to as “the water peak”
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