Optical Fiber Testing

Overview

1. The need for testing

2. Testing devices

3. Problems with today’s equipment.

4. Cost of equipment

Importance of Testing

Ensure the fiber has been Properly installed

Check IL and reflectance of all splices and connections

Providers must maintain high quality of customer service

Quickly locate problem areas for repair

Types of Testing

• End to End loss testing

• Cable Commissioning

• Splice and connector optimization

• System ORL characterization

• Dispersion verification and wavelength measurements

End to End Testing

• Both units must be referenced with the test jumpers

• Confirm power source is connected to test fiber

• Reading is only accurate if both units at same wavelength

Cable Commissioning

• Tests the cable for damage • Double checks length and attenuation• And measures the polarization mode dispersion

Reflectance

• Do to glass air interface

• Rayleigh backscattering

• Pr = Reflected Power

• Pi = Incident Power

Reflectometers

• Two types:1. Optical Time Domain Reflectometer

- Measures reflectance and ORL

- Can characterize connectors and mechanical splices

- Accuracy of plus/minus 2dB

Reflectometer

2. Optical Continuous Wave Reflectometer

- Also measures reflectance and ORL

- Some units measure bi-directional loss

- Accuracy of plus/minus 0.4 dB to 1.0 dB

Difficulties

• Light source and power meter must be referenced at the same point.

• Wavelength of light source and power meter must be the same.

• Jumpers to test equipment can wear down

Leading Manufactures

Agilent/HP Tektronix

Fluke Advantest

NetTest Fluke Networks

Cal Instruments