Modern Optical Networks - Optical Signal Processing by Silicon Photonics - page 25

(a) (b)

n

n

0

125 82.5 r (um) 125 4 r(um)

(c) (d)

n n

r (um)

125 9 4 r(um)

Fig. 3.5 Some typical index profile for optical fibers a graded index, b step index, and c disper-
sion compensating fiber [ 8 ]

geometrical properties and the number of guided modes the fibers can be catego-
rized further as multimode and single mode fibers.
Multimode fibers (MMF) are inexpensive solutions for building LAN in an
office, for example. The name MMF comes from the fact that the light travels
down the fiber in multiple paths. Graded-index fibers are usually used for LAN/
WAN equipments because the light path in this case is sinuous and regular while
in the case of step-index MMF the light path is highly angular and irregular. From
the end of 1990s, highly nonlinear (HNL) fibers were developed for super con-
tinuum generation.
Ethernet : is defined by IEEE 802 and consists of a range of standards and
media that aid the communication between devices. Wireless LAN technology is
designed to connect devices exclusive of wiring. These devices make use of radio
waves or infrared signals as a transmission medium [ 15 ] (Fig. 3.6 ).