IEEE Standard for All-Dielectric Self-Supporting Fiber Optic CableDescripción completa
FIBER OPTIC CABLE SPLICING/JOINT AND MEASUREMENT
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SyllabusFull description
Berisi dasar-dasar fiber optikFull description
OF Connector Types
DIODOS
FOA
Cable type Cable structure Technology specification
Full description
Fiber Optic Cables are high data transmission cables.Full description
Full description
3 Measurement of Numerical Aperture of FiberFull description
3704
Fibre-optic-cable-specification-pdf
Duct InstallationFull description
Cable Network Measurement
Optical Time Domain Reflectometers (OTDR) When Do You Use OTDRs? ! In LANs with splices between cables to check if the fibers and splices are good ! To test the length of the fiber on a reel
"Warning ! OTDRs should not be used to measure cable plant loss. They can not show the actual cable plant loss that system will see ! The limited distance resolution of the OTDR
OTDR
How does an OTDR work? ! The biggest factor in optical fiber loss is scattering ! In the fiber, light is scattered in all directions ! OTDR uses "backscattered light" to make its measurements ! It sends out a very high power pulse and measures the light coming back
OTDR
How does an OTDR work? Since it is possible to calibrate the speed of the pulse as it passes down the fiber, the OTDR can correlate what it sees in backscattered light with an actual location in the fiber. Thus it can create a display of the amount of backscattered light at any point in the fiber
OTDR
How does an OTDR work? The amount of light scattered back to the OTDR is proportional to the backscatter of the fiber, peak power of the OTDR test pulse and the length of the pulse sent out. If you need more backscattered light to get good measurements, you can increase the pulse peak power or pulse width
OTDR
Information in the OTDR trace They say a picture is worth a thousand words !
OTDR
Information in the OTDR trace Reflective pulses can show you the resolution of the OTDR. You cannot see two events closer than is allowed by the pulse width. Generally longer pulse widths are used to be able to see farther along the cable plant and narrower pulses are used when high resolution is needed, although it limits the distance the OTDR can see.
OTDR
Special Consideration For Multimode Fiber
OTDRs only see the middle of the multimode fiber core an OTDR will measure 6-7 dB of loss for a multimode cable plant that tests at 10 dB with a source and power meter.
OTDR
A Sample of High Performance OTDR FEATURES ! Simple one button operation ! Pre-programmable procedures ! Full on-line analysis and remote operation ! High-resolution and long-range in one unit ! Small and lightweight ! Exceptionally flexible
OTDR
Two Rules in testing a fiber Long Fiber
Long Distance Rang Long Pulse Width
Short Fiber
Short Distance Rang Short Pulse Width
More speed More accuracy
lower Averaging Mode times lower Distance Resolution settings
Higher Averaging Mode times Higher Distance Resolution settings
OTDR
A Sample of Mini-OTDR ! ! ! ! ! ! ! ! ! ! !
Start-km: 0 km - 100 km Span: 1 km - 400 km Readout resolution: 0.08 m Minimum sample spacing: 0.1m Refractive index: 1.0000 - 2.0000 Backscatter coefficient: 20 - 60 dB at 1µs Length unit: km, kft or miles Measurement points: up to 1600 Vertical scale: 0.1 - 10.0 dB/Div Read-out resolution: 0.001 dB Reflectance range: -14 dB to -60 dB
This section describes measurement procedure for the typical measurement items with the software program , one the most important is the wintrace software . In this section ,these operation items are briefly explained as measurement procedure centering around the sequence of execution . Note that the distance Range , pulse width , and other values set in this procedure are just examples , and not actually required values . When we use this software first of all , the follow specification chart have to use .
1 – The title : operator choose for the optical fiber link. 2 – Date : Set the day of measuring . 3 – Time : Set the time of measuring . 4 – Device : The kind of measuring equipment .
5 – Lambda : Select wavelength . 6 – Pulse : Set the pulse width ( 100 ns ) it shows the pulse of OTDR laser for measuring long hall . 7 – Acquisition time : Time duration to access the graph .
8 – Range : Set the distance Range . 9 – Index : Input the reflective index of the fiber ( like as 1.465 , it is suitable for step index SM ) 10 – Cable Number : Number of cable in the route , show number of cable in this part .
11 – Fiber Number : The number of fiber in the cable . 12 – Way : open ------ end OR open -----extrimity display the cursor indicates the absolute distance from the output connector to the fault location of fiber or end of fiber .
TRACE ANALYZING OTDR shows two events: 1-all reflection of the light when passing the length of the fiber. 2-Optical fiber atteuation.
Trace Graph of the OTDR
One Important Point: All fiber losses is not from manufacturing parameters. Some times bad installation increase the attenuation of the fiber, Because of: Micro and macro bending OH diffusion Strength because of extra pushing and/or pulling. Temperature increase.
At the beginning of the graph, sometimes there are two peaks, the small one is not a real loss of reflection and called ghost.
Ghost caused by multiple reflection . If the reflected light at the connector (connecting point) returns back to the source and reflects again. In this case , optical pulse may seem to be re- emitted from the source . This irregular reflection appears as a an extra peaks of loss.
1 – Slope
It shows the attenuation of the fiber
2 – Splice
3 – Reflection
Any connector or hot discontinuity may occur a reflection which is a peak of loss in the trace.
1 – Distance : Shows between the source and the events.
2 – Attenuation : Shows about the loss of events 3 – Reflectance : Shows about the Reflection of events
4 - Real.dis : Shows distance between events 5 – Slope : Shows slops between events
Field Test Instrument 1) OTDR 2) TALK SET 3) LIGHT SOURCE & POWER METER 4) FIBER SCOPE
