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Fiber Optic Networks: Material safety - We invite you to read the article that summarizes the series of entries about indoor optical networks. After discussing the… ... Read more Fiber Optic Networks: Material safety 7 August 2020
Optical fibre and laser radiation - Laser radiation is used for data transmission in fibre optic networks. In some cases, it may carry some risk to… ... Read more Optical fibre and laser radiation 10 June 2020
How to connect a fiber optic cable in accordance to fire safety rules? - There are several guidelines aimed at ensuring the proper quality of teletechnical infrastructure. Some of them concern, among others, fire… ... Read more How to connect a fiber optic cable in accordance to fire safety rules? 11 May 2020
Fiber optic and electromagnetic radiation - Most of the telecommunications technologies use radial or microwave frequency. This is why research is constantly being carried out to… ... Read more Fiber optic and electromagnetic radiation 24 April 2020
- ABSORPTION IN A FIBRE
Absorption of energy by the fibre’s material.
- ACCEPTANCE CONE
An acceptance cone is formed based on the critical angle condition of Total Internal Reflection. In that way, solid angle of the cone is determined. Within its radius, the energy injected goes into the core, while any energy inserted with an angle higher than this solid angle results in leakage.
- ADAPTER/CONNECTOR (FIBRE OPTICS)
Centering element coupling two fibre connectors.
All Dielectric Self-Supporting overhead cable.
The loss of optical power per unit length of a fibre. Does not introduce distortions to the carried signal. Attenuation is expressed in decibels per kilometer (dB/km) or decibels per meter (dB/m).
Optical network element used for attenuating optical signal by a given value expressed in dB.
Mechanical, non-heat shrink cable sealing for fibre optic enclosures.
- CIRCULATOR (FIBRE OPTICS)
Passive fibre optic component separating optical signals transmitted on the same wavelength over one fibre in oposite directions. Optical circulators are used it telecommunication systems for transmition and recption of optical signals over one fibre using one optical wavelength.
Layer surrounding fibre’s core, having lower refractive index than the core.
- CONNECTOR (FIBRE OPTICS)
Detachable connection allowing for proper transmisson between paired fibes and ensuring reliable, mechanical contact due to proper polishing and fibre centering.
- CONNECTOR REFLECTANCE (FIBRE OPTICS)
The ratio between input power and power reflected from an optical device or end-device, expressed in dB with minus sign. For characterizing the reflected power from the end of an optical link, it is advised to use the term: return losses.
- CORE (FIBRE OPTICS)
Central part in fibre’s cross-section, surrounded by cladding of lower refractive index. Light is transmitted through the core by the Total Internal Reflection phenomena, occurying on the boundary of core and cladding.
Channel multiplexing method with coarse wavelength division allowing on one fibre for up to 18 channels separated by 20 nm distance.
Decibel. Logarithmic unit describing ratio of two values. In fibre optic telecommunication it is used for specifying insertion losses, return losses, isolation.
A logarithmic unit relative to 1 mW of power.
Phenomena arising in optical path causing a distortion in time of a signal that results in pulse deformation and broadening.
- DISPERSION – CHROMATIC
Degradation of an optical signal caused by non-ideal spectrum width of a pulse. The chromatic dispersion is composed of waveguide and material dispersions. Problematic mainly for single-mode fibres.
- DISPERSION – MATERIAL
Pulse deformation caused by the dependence of the refractive index on wavelength.
- DISPERSION – MODAL
Phenomena occurring in multi-mode fibres, causing pulse broadening. Arises from different group velocities for different modes in a considered fibre.
- DISPERSION – POLARIZATION MODE
Pulse degradation resulting from different optical paths for perpendicular components of light’s mode.
- DISPERSION – WAVEGUIDE
Signal degradation resulting from the fact that part of its power propagates in fibre’s core and part in cladding (in materials of different refractive indices). The amount of light that propagated in either of the two layers is dependent on frequency of optical wave.
- DISTRIBUTION BOX (FIBRE OPTICS)
Element of an optical network, used for termination of feeder cables. Ensures proper organisation and protection of splices, storage of fibre supply and connection to active devices.
Wavelength mulitiplexing with dense channel distribution. Enables for transmissionmultiple wavelengths, separated by e.g. 0.4 nm, 0.8 nm, 1.6 nm on one fibre.
- ENCLOSURE (FIBRE OPTICS)
Protection of undetachable fibre connections (splices).
- FBT COUPLER
Passive optical element made by streching twisted fibre units over flame of a gas-jet.
Precisely made sleeve for centric fixing and stiffening optical fibre in a connector.
Fibre Reinforced Plastic – plastic reinforced with glass fibre, employed as e.g. strengthening element for fibre optic cables.
Fiber To The Antenna – variation of FTTX technology, employed in wireless radio systems. Signal is fed by means of optical link from a Base Transceiver Station to Remote Radio Heads, situated in the vicinity of one or more antennas.
Fiber To The Building – variation of FTTX technology, where fibre is delivered directly to a building and terminated in an indoor distribution frame.
Fiber To The Curb – variation of FTTX technology, where fibre is delivered to a group of buildings and terminated in a street distribution frame.
Fiber To The Desk – variation of FTTX technology, where fibre is delivered directly to subscriber’s desk.
Fiber To The Home – variation of FTTX technology, where fibre is delivered directly to subscriber’s outlet.
Fiber To The x – optical fibre network infrastructure technology. ‚x’ specifies the place where optical fibre is delivered directly.
GigaBit Interface Converter – transceiver employed in telecomm solutions. An optical or copper interface for active devices. Because of its large dimensions, was succeded by SFP or Mini-GBIC.
Gigabit Passive Optical Network – passive optical network standard based on sharing signal from one fibre on multiple users.
- GRADED – INDEX FIBRE
Optical fibre where refractive index decreases with the distance for the center of a core. On the boundary with cladding, it reaches the value of cladding’s refractive index. Graded-index fibres are multi-mode fibres (large Numerical Aperture) of small dispersion.
High Density Poliethylen, a material from which fibre optic cables’ outer sheaths,telecom manholes and underground plastic pits are made.
- HYBRID ADAPTER/CONNECTOR
Centering element coupling two fibre connectors of different standards.
Coefficient describing equipment’s ability to resist mechanical impacts.
- IMMERSION FLUID/GEL
Material, whose refractive index value is close to the refractive index of fibre’s core. Increases reflection losses.
Coefficient describing equipment’s ability to resist environmental influence – fluids and solids.
- ISOLATOR (FIBRE OPTICS)
Optical element that passes light only in one direction.
Local Area Network – a type of computer network which interconnects devices in a constrained neighbourhood.
Light Amplification by Stimulated Emission of Radiation. Optical device emitting coherent beam of electromagnetic radiation.
- LOSSES – INSERTION
Power losses resulting from inserting new element into optical link. Expressed in logarithmic form (dB) as a ratio between power of light reaching receiver before insertion to the power received after insertion.
- LOSSES – REFLECTION
Ratio between power inserted into optical link and reflected power by the end of the link expressed with a positive sign. Describing the reflected power in a technical specs of a device, it is advised to use term: reflectance.
Low Smoke Zero Halogen – halogen free material, not sustaining flames and emmiting a limited amount of fumes while burning. Meets the fire requirements for indoor installations.
System of microtubes alternative to traditional telecomm ducts.
Tube of small diameter (3.5 up to 14 mm) employed in microduct systems.
- MINIMUM BENDING RADIUS
Parameter describing the maximum degree to which cable can be bent that will not be detrimental neither for the transmission parameters nor the internal structure.
Distribution of an electromagnetic field in a fiber corresponding to an angle of propagation of a wave.
- MULTI – MODE FIBRE
Optical fibre able to carry discrete modes of the same wavelengths but different optical paths.
- NUMERICAL APERTURE
Describes the ability of an optical fiber to accept useful energy from a transmitting/amplifying device.
Optical Distribution Frame – a passive construction for cable termination, interconnection between devices and network organization
Optical Line Termination – distribution device, central unit.
Optical Network Termination at the end user.
Optical Network Unit – device terminating optical network in a local distrubution point.
Optical Ground Wire with a central tube containing optical fibres.
- OPTICAL FIBRE
Transmission medium made of dielectric material, composed of core and cladding. In order to guide light in the core, the cladding has to have lower refractive index than the core.
Fragment of optical fibre ended by a connector on each side.
It is a possibility of performing easy reconnections with fibre optic connectors..
Fragment of optical fibre ended by a connector on one side.
- PLC SPLITTER
Passive optical network element splitting optical power, manufactured in planar technique.
Plastic Optical Fibre, a fibre where core is made of plastic instead of glass.
Passive Optical Network – network utilizing single-mode fibre as a transmission medium between OLT central device and subscriber’s termination ONT. Signal in the PON network is distributed by passive optical splitters.
- PRIMARY FIBRE SHEATH
Protective layer laid straight on an optical fibre during its production process. Protects against harmful environment.
- REFLECTOMETER, OTDR (FIBRE OPTICS)
Measurement device for analysing parameters of optical fibre links. Enables locating events like connections, splices, damages and bends.
- REFRACTIVE INDEX
Ratio between speed of light in vaccum and speed of light in a given medium.
Small From-factor Pluggable or Mini-GBIC is a compact transceiver widely used in telecommunications. Constitutes optical or copper interface for active devices. Because of small dimensions, replaces GBIC.
- SINGLE – MODE FIBRE
Fibres having core diameter and numerical aperture small enough to accept and guide only one mode.
- TOTAL INTERNAL REFLECTION
Principle of operation of an optical fibre. Phenomena taking place on a boundary of two medias of different refractive indices.
Wavelength Division Multiplexing – optical transmission technique, based on multiplexing in wavelength domain. WDM allow for parallel, simultaneous and independent transmission of many optical waves of different lengths in one fibre.
- xWDM MULTIPLEXER
Element of an optical network coupling signals transmitted on different wavelengths into one fibre. ‚x’ represents density of wavelength division.