
1
1
Introduction
Optical communication systems employ lightwaves to transmit information from one
p
lace
to a
nother
s
eparated
a
cross
d
istances
t
hat
r
ange
f
rom
a f
ew
k
ilometers
to t
hou-
sands
o
f
k
ilometers.
T
hese
s
ystems
d
eliver
i
nformation
f
rom
c
entral
e
xchanges
to h
omes
a
nd
v
ice
v
ersa
o
r
to a
nd
b
etween
m
ajor
c
ities,
r
espectively.
F
urthermore,
t
hese
d
istances
a
re
n
ow
t
ransoceanic
d
istances,
r
eaching
s
everal
t
housands
o
f
k
ilometers
a
s
s
hown
i
n
Figure 1.1. Figure 1.2 shows a map from KDD Submarine Cable Systems Inc. that shows
t
he
s
ubmarine
c
able
i
nfrastructure
i
n
t
he
A
sian
r
egion
i
n
1
996.
M
ore
d
etails
o
f
t
he
ber
c
able
ne
tworks
i
n
S
outh
E