Dispersion-shifted fiber

Fiber Optic Cable
File:Dispersion-shifted fiber.jpg A close-up of dispersion-shifted fiber
Type	Optical fiber
Manufacturers	Manufacturer 1, Manufacturer 2
Related Articles	Connectors, Communication, Fiber Types
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Dispersion-shifted fiber is a type of optical fiber that is specifically designed to minimize dispersion in long-haul telecommunications systems. It was first introduced in the 1980s by Corning Incorporated, a leading manufacturer of optical fiber.

Overview

Dispersion refers to the spreading of light pulses as they travel through an optical fiber. In traditional single-mode fibers, dispersion occurs due to the different wavelengths of light traveling at different speeds. This can cause distortion and loss of signal quality, limiting the transmission distance of the fiber.

Dispersion-shifted fiber is engineered to minimize this dispersion effect by shifting the zero-dispersion wavelength to a longer wavelength range. By doing so, it reduces the interaction between the light pulses and the fiber material, resulting in lower dispersion and improved signal quality over longer distances.

Design and Construction

Dispersion-shifted fiber is typically constructed using a pure silica core surrounded by a silica cladding. The core diameter is usually around 8-10 micrometers, while the cladding diameter is around 125 micrometers. The core and cladding are designed to have different refractive indices, allowing for the efficient transmission of light signals.

To achieve the desired dispersion characteristics, the core of the fiber is doped with small amounts of germanium oxide. This doping process alters the refractive index profile, shifting the zero-dispersion wavelength to the desired longer wavelength range.

Advantages and Disadvantages

The main advantage of dispersion-shifted fiber is its ability to minimize dispersion, allowing for longer transmission distances without significant signal degradation. This makes it ideal for long-haul telecommunications applications, where signal loss and distortion can be significant challenges.

However, dispersion-shifted fiber also has some disadvantages. One major drawback is its high nonlinearity, which refers to the fiber's tendency to generate unwanted nonlinear effects as the signal power increases. This can lead to signal distortion and limit the overall capacity of the fiber.

Applications

Dispersion-shifted fiber is primarily used in long-haul telecommunications systems, where the transmission distance is a critical factor. It is commonly deployed in submarine communication cables, where signals need to travel over vast distances across the ocean floor.

In addition to telecommunications, dispersion-shifted fiber also finds applications in other fields such as scientific research and high-speed data transmission. Its ability to minimize dispersion makes it suitable for transmitting high-quality signals over long distances, enabling various applications in these domains.

See Also

• Optical Fiber
• Fiber Optic Communication
• Telecommunications
• Corning Incorporated