Triple-Play Service Deployment

Chapter 3: Deploying and Troubleshooting Fiber Networks
Attenuation (dB)
Connector Pair
Figure 3.18 A typical OTDR trace
Fusion Splice
Connector Pair
Fiber Bend
Distance (km)
Mechanical Splice
Fiber End
Source, Power Meter, and ORL Meter Combination
With a combination of source, power meter, and ORL meter, the
operator can perform automatic continuity checks and measure
end-to-end insertion loss as well as end-to-end ORL. ORL testing is
particularly important if analog video at 1550 nm is used, because
this technology is sensitive to reflectance. Several different test
configurations can be used.
In one approach, the source is placed at one end and a power
meter at the other end. The power meter reads the power level
coming from the source. If there is no reading, this indicates the
presence of a crossover along the link or a discontinuity.When the
fiber count is high, then it becomes more difficult to identify
crossovers. The technician then can use either a VFL or move the
power meter along the fiber ports to identify the one that is
receiving the signal from the source.The insertion loss is measured
by activating the source at one end and the power meter at the
other end. Some users conduct an ORL measurement at both ends.
75