HP 86037B, Instruction Manual

Page: 146 / 204

5-26
Maintenance
Cleaning Connections for Accurate Measurements
duce a good return-loss measurement. The quality of the polish establishes
the difference between the “PC” (physical contact) and the “Super PC” con-
nectors. Most connectors today are physical contact which make glass-to-glass
connections, therefore it is critical that the area around the glass core be clean
and free of scratches. Although the major area of a connector, excluding the
glass, may show scratches and wear, if the glass has maintained its polished
smoothness, the connector can still provide a good low level return loss con-
nection.
If you test your cables and accessories for insertion loss and return loss upon
receipt, and retain the measured data for comparison, you will be able to tell in
the future if any degradation has occurred. Typical values are less than 0.5 dB
of loss, and sometimes as little as 0.1 dB of loss with high performance con-
nectors. Return loss is a measure of reflection: the less reflection the better
(the larger the return loss, the smaller the reflection). The best physically
contacting connectors have return losses better than 50 dB, although 30 to 40
dB is more common.
To Test Insertion Loss
Use an appropriate lightwave source and a compatible lightwave receiver to
test insertion loss. Examples of test equipment configurations include the fol-
lowing equipment:
• HP 71450A or HP 71451A Optical Spectrum Analyzers with Option 002 built-in
white light source.
• HP 8702 or HP 8703 Lightwave Component Analyzer system.
• HP 83420 Chromatic Dispersion Test Set with an HP 8510 Network Analyzer.
• HP 8153 Lightwave Multimeter with a source and power sensor module.
To Test Return Loss
Use an appropriate lightwave source, lightwave receiver, and lightwave cou-
pler to test return loss. Examples of test equipment configurations include the
following equipment:
• HP 8703 Lightwave Component Analyzer.
• HP 8702 Lightwave Component Analyzer with the appropriate source,
receiver, and lightwave coupler.
• HP 8504 Precision Reflectometer.
• HP 8153 Lightwave Multimeter with a source and power sensor module in
conjunction with a lightwave coupler.
• HP 81554SM Dual Source and HP 81534A Return Loss Module.