Agilent Technologies N3970A - Manual (Page 43)

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■ CLEANING INFORMAT I O N
dampened with water, to clean the external case parts. Do not
attempt to clean internally.
Do not install parts or perform any unauthorised modification to
optical devices.
* Refer servicing only to qualified and authorised personnel.
Why is it important to clean optical devices ?
In transmission links optical fiber cores are about 9 µm
(0.00035") in diameter. Dust and other particles, however, can
range from tenths to hundredths of microns in diameter. Their
comparative size means that they can cover a part of the end of
a fiber core, and as a result will reduce the performance of your
system.
Furthermore, the power density may burn dust into the fiber and
cause additional damage (for example, 0 dBm optical power in
a single mode fiber causes a power density of approximately 16
million W/m2). If this happens, measurements become
inaccurate and non-repeatable. Cleaning is, there f o re, an
essential yet difficult task. Unfortunately, when comparing most
published cleaning recommendations, you will discover that
they contain several inconsistencies. In this section, we want to
suggest ways to help you clean your various optical devices,
and thus significantly improve the accuracy and repeatability of
your lightwave measurements.