Review Perancangan Sistem Komunikasi Optik
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Transcript of Review Perancangan Sistem Komunikasi Optik
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8/13/2019 Review Perancangan Sistem Komunikasi Optik
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Review Perancangan SKO
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Power Budget
TRANSMITTER RECEIVER
Fibre, connectors and splices
Power Budget (dB)
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Fiber Optic Link Power Budget
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Fiber Optic Connectors & Splices
Connectors
Demountable
terminations for fiber
Connect to transmitters
and receivers
Splices Permanent termination
of two fibers
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Fiber Optic Splices
Permanent terminations for fiber
Specifications
Loss
Repeatability
Environment
Reliability
Back reflection
Ease of termination
Cost
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Cable, Connector & Splice Testing
Continuity testing with
visual tracer/fault locator
Insertion loss with source
and meter
OTDR testing
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Point-to-Point Links
Key system requirements needed to analyze optical fiber links:
1. The desired (or possible) transmission distance
2. The data rate or channel bandwidth
3. The bit-error rate (BER)
(a) Core size
(b) Core index profile
(c) BW or dispersion
(d) Attenuation
(e) NA or MFD
MMF or SMFLED or laser pin or APD
(a) Emission wavelength
(b) Spectral line width
(c) Output power
(d) Effective radiating area
(e) Emission pattern
(a) Responsivity
(b) Operating
(c) Speed
(d) Sensitivity
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Selecting the Fiber
Other factors to consider:attenuation (depends on?)
and distance-bandwidth product (depends on?)
cost of the connectors, splicing etc.
Then decide
Multimode or single mode
Step or graded index fiber
Bit rate and distance are the major factors
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Selecting the Optical Source
Emission wavelength depends on acceptable
attenuation and dispersion
Spectral line width depends on acceptable
dispersion (LEDwide, LASERnarrow)
Output power in to the fiber (LEDlow, LASER
high)
Stability, reliability and cost
Driving circuit considerations
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Selecting the detector
Type of detector
APD:High sensitivity but complex, high bias voltage
(40V or more) and expensive
PIN:Simpler, thermally stable, low bias voltage (5V or
less) and less expensive
Responsivity (that depends on the avalanche gain
& quantum efficiency)
Operating wavelength and spectral selectivity
Speed (capacitance) and photosensitive area
Sensitivity (depends on noise and gain)
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Typical bit rates at different wavelengths
Wavelength LED Systems LASERSystems.
800-900 nm
(TypicallyMultimode Fiber)
150 Mb/s.km 2500 Mb/s.km
1300 nm (Lowest
dispersion)
1500 Mb/s.km 25 Gb/s.km
(InGaAsP Laser)
1550 nm (Lowest
Attenuation)
1200 Mb/s.km Up to 500
Gb/s.km
(Best demo)
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Design Considerations
Link Power Budget
There is enough power margin in the system to
meet the given BER
Rise Time Budget
Each element of the link is fast enough to meet
the given bit rate
These two budgets give necessary conditions
for satisfactory operation
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SONET dan SDH
SONET Bit Rate (Mbps) SDH
OC-1 51.84 -
OC-3 155.52 STM-1
OC-12 622.08 STM-4
OC-24 1244.16 STM-8
OC-48 2488.32 STM-16
OC-96 4976.64 STM-32
OC-192 9953.28 STM-64
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Dispersion budget: point-point
example
Length of link: 200 km SMF
PMD: 0.1 ps/nm/km
Chromatic dispersion: 0.5 ps/nm/km
Speed of link: OC96~ 5 Gbps Pulse width: ?? ps
Allowable dispersion with 20% rule: ?? ps
Amplifiers every 50 km PMD: 1.0 ps
Spectral width: 0.3 nm
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Dispersion budgetsame example butat OC48(continued)
Every eighth link requires repeater
Item Descr ipt ion Amoun t
(a) PMD for 50 km, 0.1 ps/nm/km ?? ps
(b) Material dispersion, 0.5 ps/nm/km ?? ps
(c) Amplifier ? ps
(d) Total per link (a+b+c) ?? ps
(e) After eight links (8xd) ?? ps
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Design summary: 200 km OC96linkItem Description L ink Loss Dispers ion
(a)Optical fiber loss at 1310 nm: 250 kmlength at 0.35 db/km; 0.6 ps/nm/km ?? dB ?? ps
(b)
Splice loss: 10 splices at 0.1
db/splice ?? dB
(c)
Connection loss: 20 connections at
0.5 db/connection ?? dB
(d) 4 amplifiers, gain of 20 dB each ?? dB ?? ps
(e)
1 repeater, gain of 20 dB; n equally
spaced repeaters reduces dispersionby factor of n+1 ?? dB
(f) Design margin ?? dB
(g) Total link loss (a)-(f) ?? dB ?? ps
(h) Transmitter avg. output power ?? dBm
(I) Receiver input power (h+g) ?? dBm ?? ps
(j) Receiver dynamic range ?? dBm
(k) Receiver specs at BER 10-9 ?? dBm ?? ps
(l) Remaining margin (k-i) ?? dB ?? ps
OK OK OK
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Dispersion budget: point-point
example
Length of link: 200 km SMF
PMD: 0.1 ps/nm/km
Chromatic dispersion: 0.5 ps/nm/km
Speed of link: OC96~ 5 Gbps Pulse width: 200ps
Allowable dispersion with 20% rule: 40ps
Amplifiers every 50 km PMD: 1.0 ps
Spectral width: 0.3 nm
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Dispersion budgetsame example but
at OC96(continued)Item Descr ipt ion Amoun t
(a) PMD for 50 km, 0.1 ps/nm/km 1.5 ps
(b) Material dispersion, 0.5 ps/nm/km 7.5 ps
(c) Amplifier 1 ps
(d) Total per link (a+b+c) 10 ps
(e) After four links (4xd) 40 ps
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Design summary: 200 km OC96link
(a)
Optical fiber loss at 1310 nm: 200km
length at 0.35 db/km; 0.6 ps/nm/km -70 dB 120 ps
(b) Splice loss: 8splices at 0.1 db/splice -0,8 dB
(c)
Connection loss: 16connections at
0.5 db/connection -8 dB
(d) 3amplifiers, gain of 20 dB each 60 dB 3 ps
(e)
1 repeater, gain of 20 dB; n equally
spaced repeaters reduces dispersion
by factor of n+1 20 dB
(f) Design margin -10 dB
(g) Total link loss (a)-(f) -8,8 dB 61,5 ps
(h) Transmitter avg. output power -10 dBm
(I) Receiver input power (h+g) -18,8 dBm 61,5 ps
(j) Receiver dynamic range -10 to -25 dBm
(k) Receiver specs at BER 10-9 -25 dBm 40 ps
(l) Remaining margin (k-i) 6,2 dB -21,5 ps
OK OK OK