| IC: See integrated
circuit. |
| ICEA: Abbreviation for
Insulated Cable Engineers Association. A technical professional
organization that contributes to the standards of insulated cable in these
four areas: power cables, communication cables, portable cables, and
control and instrumentation. Within this organization there are
subcommittees that concentrate on one of the four areas. |
http://www.icea.net/ |
| IDP: See integrated
detector/preamplifier. |
| IEEE: Abbreviation for
Institute of Electrical and Electronic Engineers. A technical
professional association that contributes to voluntary standards in
technical areas ranging from computer engineering, biomedical technology
and telecommunications, to electric power, aerospace and consumer
electronics, among others. |
http://www.ieee.org/ |
| IF: Abbreviation for Intermediate Frequency. A frequency
to which a carrier frequency is shifted as an intermediate step in
transmission or reception. |
| IIN: See interferometric
intensity noise. |
| Impedance: The
total passive opposition offered to the flow of electric current.
Determined by the particular combination of resistance, inductive
reactance, and capacitive reactance in a given circuit. A function of
frequency, except when in a purely resistive network. |
| Impedance
Matching: The connection of an additional impedance to an existing
one in order to achieve a specific effect, such as to balance a circuit or
to reduce reflection in a transmission line. |
| Index-matching
Fluid: A fluid whose index
of refraction nearly equals that of the fibers core.
Used to reduce Fresnel
reflection loss at fiber ends. Also known as index-matching
gel. |
| Index of
Refraction: The ratio of the velocity of light in free
space to the velocity of light in a fiber material. Always greater than or
equal to one. Also called refractive index. |
n = C/V
Where:
c = The speed of light in
a vacuum.
v = The speed of the same wavelength in the fiber
material. |
| Infrared (IR): The
region of the electromagnetic
spectrum bounded by the long-wavelength extreme of the visible
spectrum (about 0.7 µm) and the shortest microwaves (about 0.1 µm). |
| Infrared Emitting Diodes: LEDs that emit infrared energy (830 nm or longer). |
| Infrared
Fiber: Colloquially, optical fibers with best transmission at
wavelengths of 2 mm or longer, made of materials other than silica glass.
See also fluoride
glasses. |
| InGaAs: Abbreviation for
indium gallium arsenide. Generally used to make high-performance
long-wavelength detectors. |
| InGaAsP: Abbreviation
for indium gallium arsenide phosphide. Generally used for
long-wavelength light emitters. |
| Injection Laser Diode
(ILD): A laser employing a forward-biased semiconductor junction as the active medium.
Stimulated emission of coherent light occurs at a PIN junction where
electrons and holes are driven into the junction. |
| In-line
Amplifier: An EDFA or other type of amplifier placed in a transmission line to strengthen the attenuated signal for
transmission onto the next, distant site. In-line amplifiers are
all-optical devices. |
|
| InP: Indium Phosphide. A semiconductor
material used to make optical
amplifiers and HBTs. |
| Insertion
Loss: The loss of power that results from inserting a
component, such as a connector, coupler (illustrated), or splice,
into a previously continuous path. |
 |
| Integrated Circuit (IC): An
electronic circuit that consists of many individual circuit elements, such
as transistors, diodes, resistors, capacitors, inductors, and other passive and active semiconductor devices, formed on a single chip of semiconducting material
and mounted on a single piece of substrate material. |
| Integrated
Detector/Preamplifier (IDP): A detector package containing a
PIN photodiode and transimpedance amplifier. |
| Integrated Systems Digital
Network (ISDN): An integrated digital network in which the
same time-division switches and digital transmission paths are used to
establish connections for services such as telephone, data, electronic
mail and facsimile. How a connection is accomplished is often specified as
a switched connection, non-switched connection, exchange connection, ISDN
connection, etc. |
| Intensity: The square
of the electric field strength of an electromagnetic wave. Intensity is
proportional to irradiance and may get used in place of the term "irradiance" when only relative
values are important. |
| Intensity
Modulation (IM): In optical communications, a form of modulation
in which the optical power output of a source varies in accordance with
some characteristic of the modulating signal. |
| Interchannel
Isolation: The ability to prevent undesired optical energy
from appearing in one signal path as a result of coupling from another
signal path. Also called crosstalk. |
| Interference: Any extraneous energy, from
natural or manmade sources, that impedes the reception of desired signals.
The interference may be constructive or destructive,
resulting in increased or decreased amplitude,
respectively. |
| Interferometer: An instrument that uses the principle of interference of electromagnetic
waves for purposes of measurement. Used to measure a variety of physical
variables, such as displacement (distance), temperature, pressure, and
strain. |
| Interferometric Intensity Noise
(IIN): Noise generated in optical fiber caused by the
distributed backreflection that all fiber generates mainly due to Rayleigh
scattering. OTDRs make use of this scattering power to deduce the fiber loss over
distance. |
| Interferometric Sensors: Fiber
optic sensors that rely on interferometric detection. |
| Inter-LATA: 1. Between local access and transport
areas (LATAs). 2. Services, revenues, and functions related to
telecommunications that begin in one LATA and that terminate in another or
that terminate outside of the LATA. |
| Intermodulation (Mixing): A
fiber nonlinearity mechanism caused by the power dependant refractive index of glass. Causes
signals to beat together and generate interfering components at different
frequencies. Very similar to four
wave mixing. |
| International Telecommunications
Union (ITU): A civil international organization, headquartered in
Geneva, Switzerland, established to promote standardized
telecommunications on a worldwide basis. The ITU-R and the ITU-T are
committees under the ITU, which is recognized by the United Nations as the
specialized agency for telecommunications. |
http://www.itu.int/home/index.html |
| Internet: A worldwide
collection of millions of computers that consists mainly of the world wide
web and e-mail. |
| Intersymbol
Interference: 1) In a digital transmission system, distortion of the received signal, manifested in the temporal spreading and
consequent overlap of individual pulses to the degree that the receiver cannot reliably distinguish between changes of state, i.e., between
individual signal elements. At a certain threshold, intersymbol
interference will compromise the integrity of the received data.
Intersymbol interference may be measured by eye
patterns. |
| Intrinsic
Losses: Splice losses arising from differences in the fibers
being spliced. |
| IP: Abbreviation for Internet protocol. A standard protocol,
developed by the DOD, for use in interconnected systems of packet-switched
computer communications networks. |
| IPI: Abbreviation for intelligent peripheral interface as defined by
ANSI X3T9.3 document. |
| IR: See infrared. |
IRE
Unit: An arbitrary unit created by the Institute of Radio
Engineers to describe the amplitude characteristic of a video signal,
where pure white is defined as 100 IRE with a corresponding voltage of
0.714 Volts and the blanking level is 0 IRE with a corresponding voltage
of 0.286 Volts. |
 |
| Irradiance: Power
per unit area. |
| ISA: Abbreviation
for Instrumentation, Systems, and Automation Society. An
international, non-profit, technical organization. The society fosters
advancement of the use of sensors, instruments, computers, and systems for
measurement and control in variety of applications |
http://www.isa.org/ |
| ISDN: See integrated
services digital network. |
| ISO: Abbreviation for
International Standards Organization. Established in 1947, ISO is a
worldwide federation of national standards committees from 140 countries.
The organization promotes the development of standardization throughout
the world with a focus on facilitating the international exchange of goods
and services, and developing the cooperation of intellectual, scientific,
technological, and economical activities. |
http://www.iso.ch/iso/en/ISOOnline.frontpage |
| ISP: Abbreviation for
Internet service provider. A company or organization that provides
Internet connections to individuals or companies via dial-up, ISDN, T1, or
some other connection. |
| Isolation: See near-end
crosstalk. |
| ITU: See International
Telecommunications Union. |
