SINARAN OPTIK
  • HOME
  • Our Services
    • Hands-ON Training >
      • 1-Hari OTDR Fiber Optik Praktikal (Melayu)
      • Ujian Kecekapan Fiber Optik
      • 1-Hari Pengujian & Pentauliahan
      • 2-Hari Fiber Optik Praktikal (Melayu)
      • 4-Hari Fiber Optik Praktikal (Melayu)
    • Sijil Kecekapan >
      • MASUK UJIAN CA
    • Accessories >
      • Patchcords
      • Pigtails
      • ProtectionSleeves
    • Test Gears & Tool Kits
    • Fiber Optics Case Studies
  • Contact Us
  • Why Us
    • Trainer's Profile
    • Our Esteemed Clients
    • Hands-ON Training Photos
    • Why Attend Our Fiber Optics Training?
  • My Blogs
    • Fiber Optics Blog
    • Biz Blog (In Malay)

Testing & Commissioning Optical Fiber Link -Part 2

1/6/2017

0 Comments

 
Testing & Commissioning Optical Fiber Link -Part 1 HERE


More Examples on Calculation of Optical Power Budget

Assuming our Multimode Fiber Optics cabling configuration as below :
Picture
As per Singlemode, there are 2 common operating wavelength namely 850nm and 1300nm.
The respective attenuation or loss as illustrated below :

Picture
Figure 2 : Operating Wavelength Attenuation

Please refer to the following link for calculation of optical fiber budget formula :-
Testing & Commissioning Optical Fiber Link -
Part 1 HERE

Optical Power Budget Calculation
Using above Figure 1 fiber optics schematic diagram followings can be deduced :
a. Total length of fiber is 1km (please use OTDR to measure actual fiber length)
b. 2 nos of splicings
c. 2 nos of connectors
d. MM operating wavelength of 850 nm - 3dB/km, 1300nm - 1dB/km


Operating Wavelength at 850nm
Maximum Allowable Loss = Fiber Loss + Splicing Loss + Connector Loss

= (1 km x  3 dB/km) + ( 2 x 0.2dB) + ( 2 x 0.5dB)
= 4.4dB

Operating Wavelength at 1300nm
Maximum Allowable Loss = Fiber Loss + Splicing Loss + Connector Loss

= (1 km x 1 dB/km) + ( 2 x 0.2dB) + ( 2 x 0.5dB)
= 2.4dB
  • As such, when we do actual measurement using power meter & light source the measured loss must be less than the calculated allowable maximum loss. 
  • If the actual measurement value is higher than calculated maximum loss then most likely there will no communication or transfer data between Station A and Station B.​
On next articles  we will emphasized on
  • Calculating budget loss if there are jointings or splicings between fiber optics cable 
  • Calculating budget loss if few fiber optics cable are connected via connectors
0 Comments

Testing & Commissioning Optical Fiber Link -Part 1

1/4/2017

2 Comments

 

Calculation of Optical Power Budget 

What is Optical Power Budget ?
The optical power budget identifies how much attenuation or loss is allowed across a fiber span while still maintaining sufficient output power for the receiver.
Picture
  • Assuming that we are in the planning of installing a singlemode fiber optics cable from point A to point B for our data communication project.
  • Prior to actual fiber implementation we need to calculate before hand the allowable maximum loss  or optical power budget or optical power loss.
Picture
Figure 1 : Cabling Schematic Diagram

  • For Singlemode fiber optics the common operating wavelengths are both 1310nm and 1550nm.
  • For Multimode fiber optics the common operating wavelengths are both 850nm and 1300nm.
  • Based upon manufacturers fiber specification, the attenuation or fiber loss at both operating wave length are as follows :​​
Picture
Figure 2 : Fiber attenuation for both SM and MM

How To Calculate Optical Power Budget ?

  • The Optical Power Budget Loss is equivalent to the total loss of fiber loss + splicing loss + connector loss.
  • ​It is illustrated as below :
Picture
Figure 3 : Optical Power Budget

Fiber Loss = Length of fiber (km) x Attenuation (dB/km)
Length of fiber (km) - to get this value by using OTDR
Attenuation (dB/km) -  SM 1310nm - 0.3dB/km  & SM 1550nm - 0.2dB/km 

                                             MM 850nm - 3dB/km & MM 1300nm - 1 dB/km



Splicing Loss  = No. of splicing  x  Max splicing loss (dB)
No. of splicing  - total number of splicings done from Station A to Station B
Max splicing loss  - as per TIA/EIA recommendation  0.2dB for each splicing

​

Connector Loss  = No. of connector x Max connector loss (dB)
No. of connectors  - total number of  connectors from Station A to Station B
Max connector loss  - as per TIA/EIA recommendation  0.75 dB for  connectors
(but we take maximum connector loss at 0.5dB)


Optical Power Budget Calculation Example

Using above Figure 1 fiber optics schematic diagram followings can be deduced :
a. Total length of fiber is 1km
b. 2 nos of splicings
c. 2 nos of connectors
d. SM operating wavelength of 1310 nm - 0.3dB/km, 1550nm - 0.2dB/km

Operating Wavelength at 1310nm
Maximum Allowable Loss = Fiber Loss + Splicing Loss + Connector Loss

= (1 km x 0.3 dB/km) + ( 2 x 0.2dB) + ( 2 x 0.5dB)
= 1.7dB
Operating Wavelength at 1550nm
Maximum Allowable Loss = Fiber Loss + Splicing Loss + Connector Loss

= (1 km x 0.2 dB/km) + ( 2 x 0.2dB) + ( 2 x 0.5dB)
= 1.6dB
  • As such, when we do actual measurement using power meter & light source the measured loss must be less than the calculated allowable maximum loss. 
  • If the actual measurement value is higher than calculated maximum loss then most likely there will no communication or transfer data between Station A and Station B.​
On next articles  we will emphasized on
  • More calculated examples schematic diagram
  • How to measure fiber optics loss using power meter & light source
  • How to troubleshoot fiber optic link to find the exact causes of higher fiber loss.
2 Comments

Optical Power Loss (Attenuation) - Part 5/5

12/30/2016

0 Comments

 
Read Optical Power Loss (Attenuation) - Part 1/5 HERE
Read Optical Power Loss (Attenuation) - 
Part 2/5 HERE
Read Optical Power Loss (Attenuation) - Part 3/5 HERE
Read Optical Power Loss (Attenuation) - Part 4/5 HERE

Material Losses due to manufacturing

Rayleigh Scattering

​Fresnel Reflection

0 Comments

Optical Power Loss (Attenuation) - Part 4

12/22/2016

0 Comments

 
Read Optical Power Loss (Attenuation) - Part 1 HERE
Read Optical Power Loss (Attenuation) - 
Part 2 HERE
Read Optical Power Loss (Attenuation) - Part 3 HERE

What is Connectors Loss?

​
Picture
Connector loss in power budget calculation is considered as a pair of connectors being connected into an adapters as shown above diagram.
As per TIA/EIA specification,  the maximum loss of paired connector  is 0.75dB.
However, during power budget loss calculation we take maximum connector loss as 0.5dB so as to introduce loss buffer.
Picture
http://www.fiber-optic-transceiver-module.com/
Main factors that contribute to the fiber optics connector loss are :
  • dirty or contaminated connector (on the ferrule surface)
  • damaged fiber optics connectors end ferrule surface
  • Improper fiber optics installation or being connected - both pair connectors are not properly aligned

Picture

Other factors that may contribute to the higher losses are :
  • mismatched fiber cores
  • misaligned fiber cores
  • mismatch index of refraction
Picture
Always clean fiber optics connectors and adpaters with proper cleaning solution i.e. isoprophy alcohol
Use connector ferrule end cap to protect against dust and scratches



0 Comments

 Optical Power Loss (Attenuation) - Part 3

12/21/2016

0 Comments

 
Read Optical Power Loss (Attenuation) - Part 1 HERE
Read Optical Power Loss (Attenuation) - 
Part 2 HERE

What is Splice Loss?

  • Splice loss occurs at all splice locations. 
  • Mechanical splices normally have the highest splice loss from 0.2dB to over 1.0dB.
  • Fusion splices on the other hand have lower losses usually less than 0.1dB or even lower than 0.05dB depending upon type of reliable fusion splicer and an experienced splicing crew.
High splicing loss  caused by few number factors. However, most high splicing loss are due to workmanship for example 
  • Poor cleaving - please rotate cleaver blade if you keep getting bad cleaved​
Picture
There are high splice loss due to manufacturing defects as shown below :
Picture
Picture

End result of splicing due to fiber misalingment or lateral offset and cladding diameter mismatched - osa.org

Picture


Splicing loss

Splicing loss as indicated on the fusion splicing machine is based upon estimation only.
In order to get accurate splicing loss you need to check with OTDR as shown below. You need to obtain  splicing loss by shooting OTDR from A to B and from B to A
Picture
Picture
Assuming the obtained both splice losses are  as below : 
a. From A to B is -0.04dB
​b. From B to A is -0.02dB
Using averaging formula below the final splice loss is -0.03dB

Picture
Picture
0 Comments

 Optical Power Loss (Attenuation) - Part 2

12/20/2016

0 Comments

 
Read Optical Power Loss (Attenuation) - Part 1 HERE

What is Bend Loss ?

Bend loss occurs when fiber optics cable bends smaller than recommended fiber cable minimum bending radius or simply stated it is a loss induced by physical stress on fiber optics.
Picture

Picture

Picture
Mininim Bending Radius - Rule of Thumb
a. 10 x outer diameter fiber optic cable when cable at rest
b. 20 x outder diameter fiber optic cable during pulling


Effects of fiber optics bend on fiber optics performance ?
​When a fiber cable is bent smaller than minimum bending radius, the optical signal within the cable may refract and escape through the fiber cladding.
Picture
Bending can also permanentlsy damage the fiber by causing micro cracks, especially during cable installation when pulling forces are to be expected. The result is known as bend loss: a loss of signal strength that may compromise the integrity of the data transmission.;
This type of fiber optics bend loss is called macrobending which can add up to to a significant to fiber optics performance.

Types of Bend Loss

There are two type of fiber optics bending losses. 
a. Macrobending loss 
Macrobending loss is referred to loss induced by physical stress inserted into the fiber optics itself.
b. Microbending loss
Microbending loss is caused by imperfection in the fiber optics internal structure might be due to manufacturing process or due to pulling method.




0 Comments

Optical Power Loss (Attenuation) - Part 1

12/13/2016

0 Comments

 
  • ​Light travelling in an optical fiber loses power over distance
  • Loss of power depends on light wavelength (1310nm,1550nm, 850nm,1300nm)

Picture

  • Decibel (dB) is a unit of measured optical fiber loss 
  • The fiber optics specification loss  is expressed in dB/km.
  • The dB/km loss is multiplied by total length of fiber optics length in order to obtain total loss in dB.
Picture
Please check with fiber optic specification sheet as issued by fiber optics manufacturers

  • Optical fiber losses are categorised into extrinsic and intrinsic losses​
  • Extrinsic losses are due to bending, splice and connector loss
  • Intrinsic losses are due to fiber optics inherent loss, loss to fabrication and fresnel reflection
0 Comments

Fiber Optics Pulling

12/8/2016

1 Comment

 
It is has become a norm in telecommunication industry whereby we will see groups of electrical engineers, copper & wireless installers are closely becoming involved with fiber optic installation, termination and testing & commissionning.  
Once we fully understand the simple fiber optics guidelines then the process of installation, termination & testing would be easier to handle.
Picture
Picture


Please use following guideliines in order to secure maximum fiber optics cable performance, 
a.  Never kink the cable.
​b. Never exceed recommended bend radius during or after installation. If during cable pulling the minimum radius is 20 x than the cable outer diameter and 10 x when cable at rest.
Picture
c. Do not exceed recommended tensile loads. Use external pulling grips so as the load is applied to the cable strength member and not unto the fiber itself.
e. Monitor tensile loading or pulling force.
f Avoid pulling long lengths in one direction.

Picture

​f. Do not crush put pressure on the cable.

g. Plan to install extra cable protection in high-risk areas such as HDPE conduit.

h. Always secure cables in all installations  over ceilings or under floors.
i. Survey and plan all cable routes in order to protect cable against rodents or external stress or pressure.
j. Comply with all regulatory requirements and fire codes.
1 Comment

What is Power Meter & Light Source Test Gears?

12/6/2016

0 Comments

 
Picture

Both Light Source and Power Meter are being used to measure the actual fiber optics losses from point A to point B.
The total measuread fiber optics signal lossess included following losses :-
a. Fiber optics loss
b. Splicing loss 
c. Connector loss 

The measured readings shall be compared with calculated maximum allowable fiber optics loss from point A to point B or link loss budget as per TIA-568 specification.
​
Should the measured readings is above the calculated maximum loss then troubleshooting steps need to established in order to pinpoint the actual fiber optics components that are giving high losses.
Generally the high losses could be attributed to one or more of the followings problems :-
a. excessive fiber optics bending
b. high loss splicing workmanship
c. dirty connector
d. dirty  adapter
e. improper pulling of fiber optics cable


Picture
0 Comments

Fiber Optics Connector Cleaner

12/5/2016

0 Comments

 
Picture
Fiber Optics Connector Cleaner is to clean end surface of connector ferrule from dirt so as to enable smooth light transmission from one connector to the other with lowest possible losses.

Picture
​Alternatively you can use isoprophyl alcohol and normal cotton facial tissue that is available in any pharmacy stores to clean the end surface of fiber optics connector ferrule.
Picture
Always check end ferrule surface after cleaning either by using 100x or 400x microscope.
Picture
A good end ferrule surface (the most left photo) will provide a smooth laser transmitted from one connector to the other connector.
Otherwise you may need to repeat the cleaning process or perhaps you need to re-splice or re-terminate with new connector.
0 Comments
<<Previous

    Author

    I have been in the field of fiber optics since early 1990s.  I gained fiber optics skills and knowledge via my working experience as end-user, main contractor and sub-contractor and finally as an optical fiber enterpreneur.
     

    Archives

    January 2017
    December 2016
    August 2016
    January 2016
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    February 2015
    December 2014
    November 2014
    October 2014
    September 2014
    June 2014
    May 2014
    March 2014
    February 2014
    January 2014
    December 2013
    November 2013
    October 2013

    Categories

    All
    2.5mm Ferrule
    Color Blind
    Continuity
    Defective Connectors
    Defective Connectors
    Ferrule
    Fiber Breaks
    Fiber Color Code
    Fiber Optics Color Chart
    Fiber Optics Connectors
    Macrobending
    Optical Fiber Connector
    Sff
    TIA/EIA 598-A

    RSS Feed

About Us
Contact Us
Our Location
Our Fiber Optics Courses
Fiber Optics Tool Kits / Test Gears
Our Fiber Optics Blog
© 2022 Sinaran Optik
All rights reserved. 
 Be successful in fiber optics by acquiring the right Attitudes, Skills, Abilities and Knowledge
  • HOME
  • Our Services
    • Hands-ON Training >
      • 1-Hari OTDR Fiber Optik Praktikal (Melayu)
      • Ujian Kecekapan Fiber Optik
      • 1-Hari Pengujian & Pentauliahan
      • 2-Hari Fiber Optik Praktikal (Melayu)
      • 4-Hari Fiber Optik Praktikal (Melayu)
    • Sijil Kecekapan >
      • MASUK UJIAN CA
    • Accessories >
      • Patchcords
      • Pigtails
      • ProtectionSleeves
    • Test Gears & Tool Kits
    • Fiber Optics Case Studies
  • Contact Us
  • Why Us
    • Trainer's Profile
    • Our Esteemed Clients
    • Hands-ON Training Photos
    • Why Attend Our Fiber Optics Training?
  • My Blogs
    • Fiber Optics Blog
    • Biz Blog (In Malay)