Multi-mode Fiber.
A type of optical fiber that supports more than one propagating mode.
Numeric Aperture (NA).
The number that expresses the light-gathering ability of a fiber.
Optical Time Domain Reflectometry (OTDR).
A method of evaluating optical fibers based on detecting backscattered
(reflected) light. Used to measure fiber attenuation, evaluate splice and connector joints, and locate faults. Also, the
equipment used to perform such measurements (Optical Time Domain Reflectometer).
Photodetector.
An optoelectronic transducer, such as a PIN photodiode or avalanche photodiode.
Photodiode.
A semiconductor diode that produces current in response to incident optical power and used as a detector in
fiber optics.
Photon.
A quantum of electromagnetic energy; a particle of light.
Receiver.
An electronic device which converts optical signals to electrical signals.
Responsivity.
The ratio of a photodetector’s electrical output to its optical input in an optical fiber.
Single Mode Fiber.
An optical fiber that supports only one mode of light propagation above the cutoff wavelength.
Source.
The light emitter, either an LED or laser diode, in a fiber optic link.
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.
Splice.
An interconnection method for joining the ends of two optical fibers in a permanent or semi-permanent fashion.
Step-Index Fiber.
An optical fiber, either multi-mode or single mode, in which the core refractive index is uniform
throughout so that a sharp step in refractive index occurs at the core-to-cladding interface. It usually refers to a multi-
mode fiber.
Telecommunications Closet (TC).
An enclosed space for housing telecommunications equipment, cable terminations,
and cross-connects. The closet is the recognized cross-connect between the backbone cable and horizontal cabling.
Tight Buffer.
A cable construction where each fiber is tightly buffered by a protective thermoplastic coating to a diameter of
900
Î
m.
Transmitter.
An electronic package which converts an electrical signal to an optical signal.
Wavelength.
The distance between the same two points on adjacent waves; the time required for a wave to complete a
single cycle.
Work Area.
A building space where the occupants interact with telecommunications terminal equipment; i.e. PCs,
telephones, and other office equipment.
Appendix C - Glossary, cont.
4-5
UNIT 3
APPENDICES
APPENDICES
UNIT 4
