Усилители на активном волокне
•Активное волокно допируется одним или несколькими редкоземельными металлами
1440 1460 1480 1500 1520 1540 1560 1580 1600 1620 1640 1660 nm
EDFA ~47 nm
EDFA 52 nm
Fluoride EDFA 62 nm
Tellurite
EDFA 76 nm]
TDFA 37 nm
TDFA 35 nm
Raman + Fluoride EDFA 80 nm
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Dist. Raman + Fluoride EDFA 83 nm |
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Raman + TDFA 53 nm |
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Raman 18 nm |
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Raman 100 nm |
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Raman 40 nm |
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Raman 132 nm |
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1440 |
1460 |
1480 |
1500 |
1520 |
1540 |
1560 |
1580 |
1600 |
1620 |
1640 |
1660 nm |
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E-Band |
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S-Band |
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C-Band |
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L-Band |
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U-Band |
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2009 Information Optics, Ltd.
O |
p t i c s |
Эрбиевый волоконный усилитель (EDFA)
2009 Information Optics, Ltd.
O |
p t i c s |
Конфигурации EDFA
2009 Information Optics, Ltd.
O |
p t i c s |
Выравнивание спектра (gain equalization)
•Пассивное
–Фтористое волокно
–Оптические фильтры
•Активное
–
2009 Information Optics, Ltd.
O |
p t i c s |
Насыщение
G 1 |
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Psat |
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Gmax |
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Pin |
ln |
G |
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•Выходная мощность при которой усиление уменьшается на 3 дБ.
•Усилители мощности работают в области насыщения
2009 Information Optics,
O |
p t i c s |
Переходные процессы в EDFA
• Переходной процесс порядка мсек
2009 Information Optics, Ltd.
O |
p t i c s |
Активная компенсация
2009 Information Optics, Ltd.
O |
p t i c s |
SNR
Q (I1 I0 ) /( 0 1 )
For I0=0 and |
0 1 |
SNR 4Q2 |
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BER |
Q |
20log(Q) in dB |
SNR |
10-9 |
6 |
15.6 dB |
21.6 dB |
10-12 |
7 |
16.9 dB |
22.9 dB |
When there is an optical amplifier in the system, Bo filter bandwidth matters
Q |
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I1 I0 |
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2Iave |
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Be |
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Be |
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Be |
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Ns sp Nsp sp |
Nsp sp |
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2 1/ 2 |
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2 1/ 2 |
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(4 |
Bo |
Iave Isp |
Bo |
Isp ) |
( |
Bo |
Isp ) |
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SNR |
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Iave |
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opt |
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Isp |
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For example Be= 2.5 GHz; |
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B |
1/ 2 |
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2SNRopt |
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Q ( |
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o |
) |
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Bo=0.1 nm=12.5 GHz |
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1/ 2 |
1 |
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Be |
(4SNRopt 1) |
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2009 Information Optics, Ltd.
O |
p t i c s |
Noise Figure
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Signal-Spontaneous beating noise |
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NF |
SNR |
(RP)2 |
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4RGPnspe(G 1)Be |
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2nsp (G 1) |
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2RePBe |
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GRP 2 |
G |
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SNRo |
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Spontaneous power in a fiber amplifier is expressed as
PASE 2nsph (G 1)
Here, ASE stands for amplified spontaneous emission andis the emission spectral width.
If the amplifier is filtered through an optical filter before hitting the detector, then can be replaced by Bo.
PASE 2nsp h (G 1)Bo |
Isp 2nsp (G 1)eBo |
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2009 Information Optics, Ltd.
O |
p t i c s |
Источники шумов
2009 Information Optics, Ltd.
O |
p t i c s |