Fibre Cabling

Fiber Cabling

Two types of fiber are used for connections: multimode and single-mode.

Multimode fiber
has a fiber thickness of either 850 or 1300 nanometers (nm), and the light signal is typically provided by an LED. When transmitting a signal, the light source is bounced off of the inner cladding (shielding) surrounding the fiber. Multimode fiber can achieve speeds in the hundreds of Mbps range, and many signals can be generated per fiber.

Single-mode fiber
has a fiber thickness of 1300 or 1550 nm and uses a laser as the light source. Because lasers provide a higher output than LEDs, single-mode fiber can span over 10 kilometers and have speeds up to 100Gbps. With single-mode fiber, only one signal is used per fiber.

·         Loss factor is used to describe any signal loss in the fiber before the light source gets to the end of the fiber.

·         Connector loss is a loss that occurs when a connector joins two pieces of fibers: a slight signal loss is expected.

·         Attenuation describe the signal loose due to distance

·         Microbending is when a wrinkle in the fiber, typically where the cable is slightly bent, causes a distortion in the light source.

·         Macrobending is when there is leakage of the light source from the fiber, typically from a bend in the fiber cable. to overcome this problem over long distances, optical amplifiers can be used.

Two main standards are used to describe the transmission of signals across a fiber:

SONET is defined by the Exchange Carriers Standards Association (ECSA) and American National Standards Institute (ANSI) and is typically used in North America.

SDH is an international standard used throughout most of the world (with the exception of North America). Both of these standards define the physical layer framing used to transmit light sources, which also includes overhead for the transmission.