Reflectance
Light that is reflected back along the path of transmission, from either
the coupling region, the connector or a tertninated fiber.
Reflection
The abrupt change In direction of a light beam at an interface between
two dissimilar media so that the light beam returns into the media from
which it originated.
Refraction
The bending of a beam of light at an interface between two dissimilar media
or a medium whose refractive index is a continuous function of position
(graded index medium).
Refractive Index
See Index of Refraction.
Regenerative Repeater
A repeater designed for digital transmission that both amplifies and reshapes
the signal.
Repeater
A device which consists of a transmitter and a receiver or transceiver,
used to regenerate a signal to increase the system length.
Return Loss
See reflectance.
Ring Network
A network topology in which terminals are connected in a point-to-point
serial fashion in an unbroken circular configuration.
Rise Time
The time it takes the signal output to rise from low levels to peak value.
Usually measured from 10% to 90% of max. output.
Riser
Application for indoor cables that pass between floors. It is normally
a. vertical shaft or space.
Scattering
A property of glass which causes light to deflect from the fiber and contributes
to losses.
Sensitivity
For a fiber-optic receiver, the minimum optical power required to achieve
a specified level of performance, such as a BER.
Signal-to-Noise Ratio (SNR)
The ratio of signal power to noise power.
SIGNAL-NOISE RATIO
The ratio of signal power to noise power. Measured in dB.
Simplex Cable
A term sometimes used for a singlefiber cable.
Simplex Transmission
Transmission in one direction only.
Single-Mode Fiber
An optical waveguide (or fiber) in which the signal travels in one "mode".
The fiber has a small core diameter.
SINGLE-MODE FIBER
A fiber type which supports a single path through its core, Wavelength
dependent.
SMA
A connector type with screw threads,
Source
The means used to convert an electrical information carrying signal to
a corresponding optical signal for transmission by fiber. The source is
usually a Light Emitting Diode (LED) or Laser.
Spectral Width
A measure of the extent of a spectrum. For a source, the width of wavelengths
contained in the output at one half of the wavelength of peak power. Typical
spectral widths are 20 to 60 nm for an LED and 2 to 5 nm for a laser diode.
SPECTRAL WIDTH
The width of wavelengths in a light pulse, based on 50% intensity.
Splice
(1)A permanent joint between two optical waveguides. (2)Means for joining
two fiber ends.
Splicing
The permanent joining of fiber ends to identical or similar fibers, without
the use of a connector. See also Fusion Splicing
and Mechanical Splicing.
Splice Closure
A container used to organize and protect splice trays.
Splice Tray
A container used to organize and protect spliced fibers.
Splitting Loss
See coupling ratio.
ST
A connector type with a bayonet housing which is spring loaded "ST" stands
for "straight tip".
Star Coupler
An active or passive device where energy presented at an input port is
distributed through several output ports.
Star Network
A network in which all terminals are connected through a single point,
such as a star coupler.
Step-Index
Fiber Optical fiber which has an abrupt ("step") change in its refractive
index, due to a core and cladding that have different indices or refraction.
Typically used for single mode.
Strength Member
That part of a fiber optic cable composed of Kevlar aramid yarn, steel
strands, or fiberglass filaments that increase the tensile strength of
the cable.
Tap Port
In a coupler in which the splitting ratio between output pods is not equal,
the output port containing the lesser power.
Tap Loss
In a fiber optic coupler, the ratio of power at the tap port to the power
at the input port.
Tee Coupler
A Three-Pod Optical Coupler.
Thermal Stability
A measure of insertion loss variation as the device undergoes various environmental
changes.
Tight Buffer
Type of cable construction whereby each glass fiber is tightly buffered
by a protective thermoplastic coating to a diameter of 900 microns. High
tensile strength rating achieved, providing durability, ease of handling
and ease of connectorization.
Time-Division Multiplexing (TDM)
A transmission technique whereby several low-speed channels are multiplexed
into a highspeed channel for transmission.
Topology
The physical layout of a network.
Total Internal Reflection
Total reflection of light back into a material when it strikes the interface
of a material having a lower index at an angle below the critical angle.
Transceiver
An electronic device which has both transmit and receive capabilities.
Transducer
A device for converting energy from one form to another, such as optical
energy to electrical energy.
Transmission Loss
Total loss encountered in transmission through a system.
Transmitter
An electronic package which converts an electrical signal to an optical
signal.
Tree Coupler
A passive fiber optical component in which power from one input is distributed
to more than two output fibers.
UL
Underwriters Laboratories, Inc.
Uniformity
The maximum insertion loss difference between ports of a coupler.
Waveguide
Structure that guides electromagnetic waves along its length. An optical
fiber is an optical waveguide.
Wavelength
The distance between two peaks of an electromagnetic waveform.
Wavelength Dependence
The variation in an optical parameter caused by a change in the operating
wavelength.
Wavelength Division Multiplexing (WDM)
Simultaneous transmission of several signals in an optical waveguide at
differing wavelengths.
WDM
Wavelength Division Multiplexer - a passive fiber optical device used to
separate signals of different wavelengths carried on one fiber.
WIC
Wavelength Independent Coupler.
