ECL: Abbreviation for emitter-coupled
logic. A high-speed logic family capable of
GHz rates. |
EDFA: See Erbium-doped fiber amplifier. |
Edge-emitting Diode: An LED that emits light from its
edge, producing more directional output than surface-emitting
LED's that emit from their top surface. |
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Effective
Area: The area of a single-mode fiber that
carries the light. |
|
EGA: Abbreviation for enhanced
graphics adapter. A medium-resolution color
standard for computer monitors. |
EIA: Abbreviation for Electronic
Industries Association. An organization that
sets video and audio standards. |
http://www.eia.org/ |
EMI (Electromagnetic Interference): Any
electrical or electromagnetic interference
that causes undesirable response, degradation,
or failure in electronic equipment. Optical fibers neither
emit nor receive EMI. |
EMP (Electromagnetic Pulse): A
burst of electromagnetic radiation that creates
electric and magnetic fields that may couple
with electrical/electronic systems to produce
damaging current and voltage surges. |
EMR (Electromagnetic Radiation): Radiation made up of oscillating electric
and magnetic fields and propagated with the
speed of light. Includes gamma radiation,
X-rays, ultraviolet, visible, and infrared
radiation, and radar and radio waves. |
Electromagnetic Spectrum: The
range of frequencies of electromagnetic radiation
from zero to infinity. |
Click
to enlarge image. |
ELED: See edge-emitting diode. |
Ellipticity: Describes
the fact that the core or cladding may be elliptical
rather than circular. |
 |
EM: Abbreviation for electromagnetic. |
Endoscope: A fiber optic bundle used for imaging
and viewing inside the human body. |
E/O: Abbreviation for electrical-to-optical
converter. A device that converts electrical
signals to optical signals, such as a laser diode. |
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Equilibrium Mode Distribution (EMD): The steady modal state of a multimode fiber in which
the relative power distribution among modes
is independent of fiber length. |
|
Erbium-doped
Fiber Amplifier (EDFA): Optical
fibers doped with the rare earth element,
erbium, which can amplify light in the 1550
nm region when pumped by an external light
source. |
|
| Error Correction: In digital transmission
systems, a scheme that adds overhead to the
data to permit a certain level of errors to
be detected and corrected. |
| Error Detection: Checking for errors in data
transmission. A calculation based on the data
being sent; the results of the calculation are
sent along with the data. The receiver then performs
the same calculation and compares its results
with those sent. If the receiver detects an
error, it can be corrected, or it can simply
be reported. |
ESCON: Abbreviation for
enterprise systems connection. A duplex optical
connector used for computer-to-computer data
exchange. |
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| Ethernet: A standard protocol (IEEE 802.3)
for a 10-Mb/s baseband local area network
(LAN) bus using carrier sense
multiple access with collision detection (CSMA/CD) as the access
method. Ethernet is a standard for using various
transmission media, such as coaxial cables,
unshielded twisted pairs, and optical fibers. |
 |
Evanescent
Wave: Light guided in the inner
part of an optical fiber's cladding rather than in
the core, i.e. the portion of
the light wave in the core that penetrates
into the cladding. |
|
Excess Loss: In a fiber optic coupler, the optical loss
from that portion of light that does not emerge
from the nominal operation ports of the device. |
External Modulation: Modulation of
a light source by an external device that
acts like an electronic shutter. |
Extinction Ratio: The ratio of the low,
or OFF optical power level (PL)
to the high, or ON optical power level (PH): |
Extinction
Ratio (%) = (PL/PH) x 100 |
Extrinsic
Loss: In a fiber interconnection,
that portion of loss not intrinsic to the
fiber but related to imperfect joining of
a connector or splice. |
Eye
Pattern: A diagram that shows
the proper function of a digital system. The
"openness" of the eye relates to the BER that can be achieved. |
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