Agilent Technologies 86038B, User Manual

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Agilent 86038B Photonic Dispersion and Loss Analyzer, Second Edition
Laser Setup
TLS Selection
If more than one TLS is available, this setting allows choice of
the desired TLS and corresponding wavelength range. This
setting should be made before choosing the Start and Stop
Wavelengths in the Measurement Range Setup.
TLS Power Limit
This control sets the upper limit for TLS output power. The
86038B will set the TLS output power to the maximum level that
can be delivered over the complete normalization or
measurement range, but will not set a value higher than the TLS
Power Limit. The operator can use this setting to limit or set
TLS output power. A limit may for example be useful when
measuring an amplifying device, to avoid exceeding the input
power limit of the receiver (0 dBm). The maximum deliverable
output power depends primarily on the wavelength range, but
also somewhat on the sweep speed and wavelength increment.
An appropriate limit setting at normalization can be used when
trying measurements at different increment and IFBW settings,
in order to assure that the measurement can always be made at
the same power level. When the measurement cannot be made at
the same power level, the normalization data will be
invalidated.
The 81600B #200 laser, for example, provides –1 dBm over its
full wavelength range and +3 dBm over the range of specified
dynamic performance. For other tunable laser sources please
refer to the individual TLS specification. At higher TLS power
levels, amplitude dynamic range and group delay noise is
improved, but amplitude-to-phase conversion errors increase,
so use of phase dynamic accuracy (PDA) correction is more
important.
If the power limit is set higher than the TLS can deliver over the
measurement range, then the limit does not change the power
used by the 86038B.