What Is an Optical Cable?
Optical cables are hollow cables made of glass or plastic ; they are also called fiber-optic cables.
They provide a path for light to travel, which is how they transmit information.
Optical communication using optical fiber is less susceptible to noise than telecommunications using metal cables and thus has the advantage of providing stable, high-quality communication.
The drawback of using light for communication is attenuation, but efforts are being made to solve this problem through the structure of optical cables and amplification at relay points.
Uses of Optical Cables
Optical cables are used for high-speed communication on fixed lines of the internet.Different optical cables are used for such optical communication depending on the communication distance and speed.
Optical cables connecting a fixed line from a base station to a home require high-speed communication over long distances, so cables with a small inner diameter are used to communicate at a single wavelength, called single mode.
On the other hand, optical cables with a large inner diameter are used for short-distance ethernet through media converters for multimode communication using multiple wavelengths.
In addition to these information and communication technologies, optical cables are also used for lighting by drawing light from a light source.
Principle of Optical Cable
Light has the property of traveling in a straight line, but it is gradually attenuated by scattering.Therefore, optical cables are designed to minimize light scattering.
Transmission of light using optical cables is performed by repeated total reflection of light inside the fiber.Total reflection means that, when light enters a medium with a large refractive index into a medium with a small refractive index, if the angle of incidence is larger than the refractive angle, all the light is reflected and none is transmitted through the medium.
Optical cables have a double structure called a cladding and a core, and light comes through the core.
The core is designed to have a higher refractive index than the cladding, so the incident light is repeatedly reflected and travels through the core in a confined manner.
However, if the cable is bent in the middle, the angle of incidence increases, resulting in light loss.Therefore, as the distance increases, the risk of such light loss increases.Optical amplifiers are used to amplify the attenuated light again to improve this situation.
Types of Optical Cables
There are two types of optical cables: single-mode fiber (SMF) and multimode fiber (MMF).
1. Single-Mode Fiber
Single-mode fiber cables are characterized by a narrowly designed range over which light can pass, resulting in a single mode of light transmission and reduced attenuation. Therefore, transmission over long distances and at high speeds is possible. Although it has high performance, it is expensive, so it is generally used for communication between facilities.
2. Multimode Fiber
Multimode fiber cables are designed to have a large range of light transmission, and since light is transmitted in multiple modes, data loss is likely to occur due to the dispersion of light among each other. Therefore, it is suitable for short-distance communications and is used for laying lines within a facility. This makes them inexpensive.
Optical cables are divided into LC connectors, SC connectors, FC connectors, etc., depending on the shape of the connector. SC connectors are the most common type of connector. FC connectors use a screw-tightening method for connection and are characterized by their high cable fixing force.