Swept And Stepped Measurement Modes - Agilent Technologies 86038B User Manual

Swept and Stepped Measurement Modes

Agilent 86038B Photonic Dispersion and Loss Analyzer, Second Edition
The measurements performed by the 86038B involve tuning the
laser source while observing changes in the recovered RF
amplitude and phase. The wavelength can be changed in either a
stepped or a swept (continuous) mode. The 86038B includes
advances to optimize the performance with continuously swept
wavelength measurements, which greatly reduce measurement
time and facilitate the use of small wavelength increments for
high wavelength resolution applications. The time reduction
also reduces the sensitivity of GD/CD measurements to GD drift
in the device, such as a long fiber with changing temperature.
However the stepped mode may be preferred for measurements
at a limited set of wavelengths, or to allow averaging many
measurement samples to minimize noise. This mode also
minimizes the elapsed time involved in individual DGD
measurement points and thus minimizes the influence of GD
drift on the result, which can be important for long fibers with
low PMD. The stepped measurements may also be desirable in
some cases because each measurement point is made at a fixed
wavelength, rather than accumulated over the increment.
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