mobile | classic
Dataweek Electronics & Communications Technology Magazine





Follow us on:
Follow us on Facebook Share via Twitter Share via LinkedIn


Search...

Electronics Buyers' Guide

Electronics Manufacturing & Production Handbook 2019


 

iOLM technology eases FTTx/PON network testing
23 January 2013, Test & Measurement

Of the current test methods for testing FTTx (Fibre to the ‘x’, with x being a placeholder for various end-points) and PON (passive optical network) installations, OLTS, using an optical loss test set (optical power meter and light source) to characterise a link is easy; however it has one major limitation: it cannot locate the problems on the link. Furthermore, an OLTS requires two units and two technicians, thus increasing OPEX.

Figure 1. End-to-end test with a pair of OLTS units. This method may be fast, but will not locate the problem on the link.
Figure 1. End-to-end test with a pair of OLTS units. This method may be fast, but will not locate the problem on the link.

The most popular test method during construction and in certifying FTTX/PON installations is an OTDR (optical time domain reflectometer). A well trained and skilled optical technician can identify and locate problems on a link, using multiple acquisitions with different OTDR test settings and after various manual OTDR trace comparisons.

Figure 2. Incomplete OTDR test results on a 1x32 PON due to improper testing parameters set by a technician who is lacking OTDR testing experience.
Figure 2. Incomplete OTDR test results on a 1x32 PON due to improper testing parameters set by a technician who is lacking OTDR testing experience.

The shift from copper to fibre and the explosion of fibre deployments has created a shortage of skilled and experienced technicians. Combine this with budget constraints, lack of credible training facilities, practical experience and the result is an increased risk of improper testing, misdiagnoses, unusable OTDR results and repeat repairs/truck rolls.

Figure 3. Portable test setup with launch and receive fibres for a PON-line certification with a 1x32 splitter.
Figure 3. Portable test setup with launch and receive fibres for a PON-line certification with a 1x32 splitter.

The complexity of a PON/FTTx network requires skilled optical technicians to set different acquisition parameters on the OTDR to get the required information. Single OTDR measurement and auto test settings on today’s OTDRs are incapable of fully characterising this type of network.

To overcome this limitation, skilled technicians perform multiple additional acquisitions on the OTDR with other parameters to fully characterise the link.

Figure 4. Example of test results. All the information, including diagnostics, is provided in a single view.
Figure 4. Example of test results. All the information, including diagnostics, is provided in a single view.

Portable applications

EXFO’s new test solution is an ‘intelligent’ OTDR. Essentially it is a software application that runs on the test unit that is able to set and take multiple and variable acquisitions, then analyse the information to generate a detailed linear diagram about every element on the link, in a single-button operation, providing maximum simplicity for expert-level link characterisation.

This new test method makes every technician a fibre-optics expert, whether they are testing in the field or from the central office. Plus, it does not require the parameter settings used in traditional OTDR testing, which means no distance, pulse width or averaging time setting with detection threshold setting required.

iOLM (intelligent Optical Link Mapper) technology stems from the need to create optimal testing technology for PON networks, as this is the most challenging network to test because of its short link lengths and many closely spaced elements, such as splices, connectors and splitters.

As shown in Table 1, the maximum IL difference between iOLM and the reference method (PM/LS) is 0,64 dB, which compares favourably to the OLTS method. Based on the PM/LS and the OLTS results, an experienced technician could have suspected a macrobend on the line because the difference in loss is more than 1 dB between 1310 and 1550 nm.

Table 1. IL test results from the different methods.
Table 1. IL test results from the different methods.

However, he would have no clue as to the location of the macrobend. He could therefore use an OTDR and a different combination of pulse widths to find the macrobend himself. With iOLM any technician will be able to clearly see that there is a macrobend immediately after the splitter (see Figure 5 showing a test conducted from ONT to OLT).

Figure 5. Image showing the position of a macrobend once analysed by a portable OTDR with multi-pulse acquisition and analysis capabilities.
Figure 5. Image showing the position of a macrobend once analysed by a portable OTDR with multi-pulse acquisition and analysis capabilities.

The test method is a one-end, single-unit testing method with the ability to provide clear diagnostics and discovered elements in a single view.

Comparing ORL measurements (Table 2), the maximum difference between the ORL meter and iOLM is 0,84 dB, which is small enough to locate any ORL problem.

Table 2. Table showing the different ORL test results.
Table 2. Table showing the different ORL test results.

So what is causing an ORL issue on the line?

This is caused by connector reflectance, but according to the ORL results, we are below the 32 dB threshold. Now, if we look at the results in Figure 6, we can see that there is one highly reflective connector that needs to be fixed (exceeds the -55 dB threshold).

Figure 5. Image showing the position of a macrobend once analysed by a portable OTDR with multi-pulse acquisition and analysis capabilities.
Figure 5. Image showing the position of a macrobend once analysed by a portable OTDR with multi-pulse acquisition and analysis capabilities.

This is what we are looking for when testing with an ORL meter (or OLTS) in both directions. We want to know the direction of the high ORL because that is where the high reflective connector is. Obviously, we would have missed it with the ORL meter or the OLTS, providing a clear advantage for the iOLM.

For more information contact Chris Nel, Lambda Test Equipment, +27 (0)12 349 1341, chris@lambdatest.co.za, www.lambdatest.co.za


Credit(s)
Supplied By: Lambda Test
Tel: +27 12 349 1341
Fax: +27 12 349 1493
Email: chris@lambdatest.co.za, ockie@lambdatest.co.za
www: www.lambdatest.co.za
  Share on Facebook Share via Twitter Share via LinkedIn    

Further reading:

  • Body-worn EMF monitor
    29 May 2019, Accutronics, Test & Measurement
    For those working with high-intensity electromagnetic fields (EMF), such as in the near field region of radar antennas, broadcast transmitters or cellular base stations, it is vital to wear personal safety ...
  • Optical spectrum analyser
    29 May 2019, Coral-i Solutions , Test & Measurement
    Anritsu announced the sales launch of the new MS9740B spectrum analyser which has been developed for evaluating the output characteristics of optical active devices used by optical communications systems. ...
  • New scan capabilities for EMI receiver
    29 May 2019, Concilium Technologies, Test & Measurement
    Keysight Technologies has added time domain scan (TDS) and real-time scan (RTS) capabilities to the N9048B PXE electromagnetic interference (EMI) receiver, enabling real-time measurements and diagnostics ...
  • Passive intermodulation analyser
    30 April 2019, Actum Electronics, Test & Measurement
    Passive intermodulation (PIM) is one of the main causes of faults in modern networks. PIM can significantly reduce the network quality with regard to range and data transmission. PIM is caused by a number ...
  • Vacuum test fixture
    30 April 2019, Electronic Industry Supplies, Test & Measurement
    With its newly designed vacuum test fixtures, Ingun has simplified mass testing of a small number of PCB (printed circuit board) versions. The vacuum test fixture combines intuitive handling and a robust, ...
  • Optical spectrum analyser
    30 April 2019, Coral-i Solutions , Test & Measurement
    Anritsu announced the sales launch of the new MS9740B spectrum analyser which has been developed for evaluating the output characteristics of optical active devices used by optical communications systems. ...
  • New scan capabilities for EMI receiver
    30 April 2019, Concilium Technologies, Test & Measurement
    Keysight Technologies has added time domain scan (TDS) and real-time scan (RTS) capabilities to the N9048B PXE electromagnetic interference (EMI) receiver, enabling real-time measurements and diagnostics ...
  • Body-worn EMF monitor
    30 April 2019, Accutronics, Test & Measurement
    For those working with high-intensity electromagnetic fields (EMF), such as in the near field region of radar antennas, broadcast transmitters or cellular base stations, it is vital to wear personal safety ...
  • Passive intermodulation analyser
    27 March 2019, Actum Electronics, Test & Measurement
    Passive intermodulation (PIM) is one of the main causes of faults in modern networks. PIM can significantly reduce the network quality with regard to range and data transmission. PIM is caused by a number ...
  • Arbitrary waveform generator
    27 March 2019, Vepac Electronics, Test & Measurement
    Tektronix launched the AWG70000B arbitrary waveform generator with new features that enable it to fully support the testing of complex electronic warfare and wireless communications systems that require ...
  • Battery optimisation software for IoT devices
    27 February 2019, Concilium Technologies, Power Electronics / Power Management, Test & Measurement
    Keysight Technologies has introduced the X8712A IoT device battery life optimisation software solution, to ensure optimal battery life prior to device deployment to accelerate troubleshooting and device ...
  • Calibration and the challenges of choice
    27 February 2019, Concilium Technologies, Test & Measurement
    A poor or incomplete calibration can lead to significant errors in your measurements. The time to develop a product may exceed your original schedules and production yields may be too low if the test ...

 
 
         
Contact:
Technews Publishing (Pty) Ltd
1st Floor, Stabilitas House
265 Kent Ave, Randburg, 2194
South Africa
Publications by Technews
Dataweek Electronics & Communications Technology
Electronics Buyers’ Guide (EBG)

Hi-Tech Security Solutions
Hi-Tech Security Business Directory

Motion Control in Southern Africa
Motion Control Buyers’ Guide (MCBG)

South African Instrumentation & Control
South African Instrumentation & Control Buyers’ Guide (IBG)
Other
Terms & conditions of use, including privacy policy
PAIA Manual





 

         
    Classic | Mobile

Copyright © Technews Publishing (Pty) Ltd. All rights reserved.