???? Fiber Optic Testing

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???? Fiber Optic Testing
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???????????

• ??????
• ?????????????
• ??????,????????????
• ??TIA/EIA 568A, ISO11801, EN50173
• ????????
• ?????????????
• ?????????????
• ??10BASE-FL,Token Ring,100BASE-FX,
  1000BASE-SX,1000BASE-LX,ATM,Fiber Channel

3
TIA/EIA 568A Standard

• ??(Cable)
• ????????? (at 850 nm) 3.75 dB
• ????????? (at 1300 nm) 1.5 dB
• ????????? (at 1310 nm) 1.0 dB
• ????????? (at 1550 nm) 1.0 dB
• ??? Connections (Duplex SC or ST)
• ?????(adapter)?? 0.75 dB
• ????(Splice)?? 0.3 dB
• ????Link Lengths (backbone)
• Segment HC-IC IC-MC
• 62.5/125 ??Multimode 500 m 1500 m
• 50/125 ??Multimode (under proposal)
• 8/125 ??Singlemode 500 m 2500
  m

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IEEE 802.3z(Gigabit Ethernet)????????

• 1000BASE-SX (850 nm laser) ??
  ??
• 62.5 ????? 3.2 dB 220 m
• 50 ????? 3.9 dB 550 m
• 1000BASE-LX (1300 nm laser)
• 62.5 ????? 4.0 dB 550 m
• 50 ????? 3.5 dB 550 m
• ???? 4.7 dB 5000 m

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??????? Calculating Loss Limits

• ??
• ??TIA 568A (1300nm)
• ???? ?? ??
• ???? 1.5dB/km 0.5km 0.75dB
• ????? 0.75dB 1 0.75dB
• ?????? 0.3dB 0 0
• ??? 1.5 dB
• ?????,????????
• DSP-4000????????????

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???????

• ??????(???)
• ?????????
• ???????
• ???????
• ????
• ???????
• ????????
• ????(??????)

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????

• Optical Power - an absolute measurement of power
  measured in dBm as a reference to one milliwatt
  of power
• ???-?1??????????????
• Attenuation (Loss) - the amount of light that is
  lost in a fiber path. Is measured in dB as a
  relative reading of power.
• ??(??)-??????,?????
• Dispersion - spreading over time of a ray of
  light as it travels through a fiber
• ??-?????????

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??(??)??

• ????????
• ???????????
• ???????

?????????????? ??????????????
SignalSource
SignalReceiver
dB Loss
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???????????

• 1. ???????????(???)

• ?
• ??? -20 dBm
• ?????? ???)

??? ????
??? ????
Detector
Source
2. ???????????(????????)

• ???? -23 dBm

??? ????
??? ????
Source
Detector
Additional Adapter
3. ????????(???3dB)
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??????

• ??????
• ???,????
• ?3dB,???????2?
• ?10dB,??????10?

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?????? Losses In Fiber Paths
??????
?????
?????
????
????
????? ??????
????? ??????
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????? Bending Optical Cable

• ?????????
• ????????2??????,????????????
• ????????????

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???????

• ????
• ????
• ????
• ????

?????????????????????.

• ??????????????????.
• ?????????, ??????????????
• ???? (???, ??, ??)
• ???? (????????)

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?????????

• ??????
• ?????????
• ??????????
• ????????
• ????
• ??????OTDR
• ??????
• ??????

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?????FT120/FT140

• ????
• FT120(200?),???? MM
• FT140(400?),???? SM
• ???????????????
• ??????????????????
• ?????????LED?????

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Inspecting The Fiber Termination
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???? Loss Testing

• ????????
• ??
• ????????????
• ????
• ?????????
• ?????????????????
• ????
• ????
• ???????

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??????? Dual-fiber loss measurement
In
Out
In
Out
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????????
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LED vs. VCSEL
Cladding
????? ????
LED Overfilled Launch
Core
Cladding
Multimode Fiber
?????????????
Cladding
VCSEL Concentrated Launch
Core
Cladding
(Gigabit)
Multimode Fiber
LEDs???????
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????????? Testing Gigabit over Multimode Fiber
Source
Power Meter
0.57 dB of loss due to inaccurate test method

• Source Type Loss
• 850 nm LED 2.69 dB
• 850 nm laser (VCSEL) 2.12 dB

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OTDR ??????
????

• ?????
• ????????
• ??????
• ????????
• ??????????????
• ????????????????
• ???(US10K-40K)

??
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??????
UTP ????
??????
????
HUB
HUB
WIRING CLOSET
WIRING CLOSET
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????
UTP ????
??????
???
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????? Fiber Loss Measurement
TIA-568-A?????
??????
??? ????
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????? ?????
???????????????????????
?????
Launch Patch Cable
Receiving Patch Cable
????-???????? ??
Fiber Optic Link-under-test
Launch Patch Cable
Receiving Patch Cable
Detector
Adapter
Adapter
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???????
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????? Single Fiber Measurement
Fiber Under Test
Source
Out
In
??????

• ???????
• ???????
• ???????
• ??????

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?????? Loopback Loss Measurement
Fiber 1
Out
In
Fiber 2

• ???????
• ???????
• ???????
• ??????

??????
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???(Duplex)????
?????
TX
RX
Patch Cable 1
Patch Cable 2
????-???????????
TX
RX
Fiber Under Test
Test Jumper Set
Patch Cable 1
Patch Cable 2
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??????Fiber System Summary

• ???????????
• ??????????
• ?????????????
• ??????????????????

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Thank You