What is the fiber fiber scattered? How to scatter compensation?

Fiber scattering is a phenomenon that occurs in optical fibers where light is scattered in different directions due to fluctuations in the refractive index of the fiber material. The scattering of light in the fiber causes attenuation, or the loss of signal strength, as the light travels down the length of the fiber. This attenuation is called "scattering loss," and it is one of the primary factors that limits the maximum distance that a signal can be transmitted over an optical fiber.

Types of Fiber Scattering

There are two types of fiber scattering: Rayleigh scattering and Mie scattering.

Rayleigh Scattering: Rayleigh scattering is the most common type of scattering that occurs in optical fibers. It occurs when the refractive index of the fiber material fluctuates on a small scale. These fluctuations cause the light to scatter in all directions, which results in attenuation of the signal.

Mie Scattering: Mie scattering is less common than Rayleigh scattering and occurs when the refractive index of the fiber material fluctuates on a larger scale. This type of scattering is typically caused by impurities or defects in the fiber material.

Scattering Compensation

To overcome the attenuation caused by scattering, a process called "scattering compensation" is used. Scattering compensation is the process of increasing the signal strength at the receiving end of the fiber to compensate for the loss of signal strength due to scattering.

There are several techniques used for scattering compensation, including:

Forward Error Correction (FEC): FEC is a technique that uses redundant data to detect and correct errors in the transmitted data. By using FEC, the signal strength at the receiving end can be increased to compensate for the loss of signal strength due to scattering.

Raman Amplification: Raman amplification is a technique that uses a Raman amplifier to increase the signal strength in the fiber. The Raman amplifier uses a pump laser to excite the molecules in the fiber, which in turn amplifies the signal.

Erbium-Doped Fiber Amplifiers (EDFAs): EDFAs are another type of amplifier used for scattering compensation. EDFAs use an erbium-doped fiber to amplify the signal in the fiber. The erbium ions in the fiber are excited by a pump laser, which in turn amplifies the signal.

Dispersion Compensation: Dispersion compensation is another technique used for scattering compensation. Dispersion is the phenomenon where the different wavelengths of light in the fiber travel at different speeds, causing the signal to spread out and attenuate over distance. Dispersion compensation uses techniques such as dispersion compensating fibers (DCFs) or dispersion compensating modules (DCMs) to offset the dispersion in the fiber and increase the signal strength.

Polarization Mode Dispersion (PMD) Compensation: PMD is the phenomenon where the polarization of the light in the fiber changes due to the stress on the fiber. PMD compensation uses techniques such as polarization controllers or polarization-maintaining fibers to maintain a constant polarization of the light in the fiber and increase the signal strength.

Conclusion

Fiber scattering is a phenomenon that causes attenuation of the signal in optical fibers. Scattering compensation is the process of increasing the signal strength at the receiving end of the fiber to compensate for the loss of signal strength due to scattering. Techniques such as forward error correction, Raman amplification, erbium-doped fiber amplifiers, dispersion compensation, and polarization mode dispersion compensation are used for scattering compensation. By using these techniques, the maximum distance that a signal can be transmitted over an optical fiber can be increased.