Fibre-Optic Cable

WDM is one of the implementation of #Multiplexing, classified as #Frequency Division Multiplexing (FDM), which utilises the feature of the light as a wave. Since light waves of different wavelengths do not interfere with one another within a medium, it is possible to multiplex different channel travelling in different wavelengths in a single Fibre-Optic Cable simultaneously.

SONET is a #Physical Layer #optical technology that supports from 155 Mbps up to 10 Gbps high transmission rates for Metropolitan Area Network (MAN) using #Time-Division Multiplexing (TDM) multiplexing scheme. It provides means of transportation to Data Link Layer# protocols and of conversion using Fibre-Optic Transmission Systems (FOTS), which is a Modulator. It has extensive OAMP (operation, administrative, maintenance and provisioning) capabilities. This allows precise fault detection and a rapid (50 ms) failover (switching to a redundant or standby computer server, system, hardware component or network upon the failure or abnormal termination of the previously active application). Its speed is range from 51.84 Mbps (OC-1) to 9953.28 Mbps (OC-192).

Single-Mode #Fibre-Optic Cable composed of four layers, from outer layer to inner layer: the jacket (900 µm), buffer (250 µm), cladding (125 µm), and core (8-9 µm). Due to its small core diameter (compare to Multimode Fibre-Optic Cable), it allows only one mode light propagation. However, in compensation, the light pulse could travel in long distance, and it can carry high bandwidth without worrying too much about distortion.

Polarisation or Mode Distortion is an optical phenomenon where high bandwidth signals, typically higher than 10Gb, tend to broaden as they travel down the #Fibre-Optic Cable. This could cause inter-signal interference.

Optical Ethernet utilises Gigabit Interface Converter (GBIC) in order to convert an #Ethernet stream to an optical signal. It is currently the simplest and cheapest form of #optical transport.

Multiplexing is a method of combining multiple data streams onto a single physical or logical connection such as a wire, Fibre-Optic Cable# or link. Most of the time, the multiplexed data would be reconstructed at the receiving end.

Multimode #Fibre-Optic Cable is composed of three layers, from outer layer to inner layer: the coating that protects the inner layers, the cladding that keeps light in the core, and the silica or plastic core that carriers the signal. The light could propagate in the form of multiple wavelengths where each could take a slightly different path due to its large core diameter (typically 50-100 µm, larger than Single-Mode Fibre-Optic Cable). However, its covering distance is much shorter, less than 2 km, due to possible dispersion.

Modulator is a machine or software that could transform channel code words to a corresponding analogue symbol. For example, the symbol could be into waveform when there is a need to travel in Fibre-Optic Cable.

MAN is a network that covers a geographic region with a size of a metropolitan. It connects various Local-Area Network (LAN)# to each other, and provides sufficient connections to the Wide Area Network (WAN)#. Most of the connection are done by Fibre-Optic Cable# and its technologies using pulses of light.

DPT is an #optical networking technology that utilises SONET/SDH framing and employs intelligent protection switching in the event of fibre facility or node failure or signal degradation. Electrical signals and light can be converted to each other form via Fibre-Optic Transmission Systems (FOTS), whihc is a Modulator. It uses a bidirectional, counterrotating ring structure for metro applications, and a star structure with a central switching device for service point-to-point backbones.

Dispersion and Non-Linearities is an optical phenomenon due to a function of distance and speed. In #optic networking, this could mean the erosion of the signal clarity.

CWDM uses wavelength-specific pairs of Gigabit Interface Converters (GBIC) connected to a Switch# pair in order to #multiplex up to 8 #Fibre-Optic Cable signals onto a single fibre. Each GBIC pair is tuned to a specific frequency that allows the switch to add (mux) or pluck out (demux) a single beam of light (data stream). However, CWDM is unable to be amplified, which limited its maximum distance to 80 km for point-to-point or a ring circumference of 30 km.

Chromatic Distortion is caused by Dispersion and Non-Linearities#, that is the spreading of the signal over distance. In #networking, it can cause signals to interfere with each other.