Page 296 - Optical Switching And Networking Handbook

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Glossary 281

Graded-index fiber Optical fiber in which the refractive index
of the core is in the form of a parabolic curve, decreasing toward
the cladding.
Grooming Consolidating or segregating traffic for efficiency.

Half-duplex A bi-directional link that is limited to a one-way
transfer of data; that is, data can’t be sent both ways at the same
time.
Hard-optics The hardware technologies that create and trans-
port light, such as DWDM, FEC, Raman amplification, tunable
dispersion compensators, Variable Optical Attenuators, dynamic
spectral gain compensators, Micro-Electro-Mechanical Systems
(MEMS), and Optical Spectrum Analyzers (OSAs).

Index of refraction Also refractive index. The ratio of the veloc-
ity of light in free space to the velocity of light in a fiber material.

Infrared (IR) Light from the region of the spectrum with wave-
lengths between 750nm (red) and 0.1mm (microwave).

Intelligent optical network A dynamic flexible network of vir-
tual lightpaths that is “light” from end to end and delivers an
abundance of cost-effective, usable bandwidth.
Intelligent optical networking Bringing network intelligence
to the optical domain; the creation, configuration, and manage-
ment of virtual lightpaths within the optical domain. A new class
of products for the development of an intelligent optical network.
Interleave The capability of SONET to mix together and trans-
port different types of input signals in an efficient manner, thus
enabling higher-transmission rates.

Isochronous All devices in the network derive their timing sig-
nal directly or indirectly from the same primary reference clock.

Jacket The outer, protective covering of the cable.
Jitter Small and rapid variations in the timing of a waveform
due to noise, changes in component characteristics, supply volt-
ages, imperfect synchronizing circuits, and so on.

Kilobits per second One thousand bits per second.