salabljenje snage svetlosi u optickom vlaknu
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7/22/2019 Salabljenje snage svetlosi u optickom vlaknu
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. 1, 2
,
VII ,
.
. cut-back.
.
.
. .
, .
( 1). .
1n ,
2n .
.
,
c . ,
( )1 2 1sin /c n n
= . c > , c < ,
.
1.
1
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.
. ,
,
.
2n 1n
.
.
[1-3].
,
0 max <
, max
. ,
2 2max 1 2
sin n n = .
.
,
. (dB)
( )10 log /in out a P P= , inP , outP . 10 dB
.
:'( ) (0) zP z P e = (1)
(0)P , 0z= , ( )P z
, z . '
(eng. attenuation constant). ' -1km .
dB/km:
( ) ( )10log / 10 ' login out a P P z e= = (2)
/ 4.343 'a z = (3)
.
Rayleigh- .
.
, .
,
2
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, : 850 nm, 1310 nm,
1550 nm. 800 nm 900 nm, 1250 nm 1350
nm 1500 nm 1600 nm ,
. --- (PMMA) , ,
: 520 nm, 570 nm, 650 nm,
73 dB/km, 64 db/km 130
dB/km, ( 2).
2. PMMA [5]
. cut-back [4].
: , , 1L , , 2L .
inP , (2)
1
2 1 2
10log L
L
P
L L P =
. (4)
1LP 2LP , .
3. .
3
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3.
: 1 550nm = , 2 625nm = , 3 700nm =
4850nm = . 5.47 V.
,
1.
(4).
. PMMA
(nm)
10.5mL =
( )VU
28mL =
( )VU
( )dB/m
550 0.16 0.13 0.12625 0.45 0.23 0.38
650 0.19 0.14 0.17
850 4.32 0.44 1.32
2.
.
.
.
1. Cherin A. H.,Introduction to optical fibers,New York, McGraw-Hill, 1983.
2. ., ,
, XXV , . , 2007, . 182-187.3. .,
, ( ), , 2007.4. Marcuse D.,Principles of Optical Fiber Measurements,New York, Academic Press, 1981.
5. Zeimann O., Krauser J., Zamzow P.E., Daum W., POF Handbook, Berlin, Springer-Verlag, 2008.
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