Performing Stimulus-Response Measurements - Agilent Technologies 83438A User Manual

Performing Stimulus-Response Measurements

This section shows you how to perform stimulus-response measurements. The
combination of using the Agilent 83438A for broadband stimulus and the opti-
cal spectrum analyzer for selective response provides the following benefits:
• All wavelengths are available simultaneously
• Fast measurement speeds
• Small coherence length
• High dynamic range and high resolution
Measurements for DWDM systems
The following figure shows a system which is well suited for characterizing
dense wavelength-division multiplexed (DWDM) components. Because of the
high-power density of the Agilent 83438A, you can easily characterize such
items as the crosstalk of dimultiplexers and the reverse path of optical isola-
tors.
The polarization controller is used to characterize polarization dependencies
of a device. For example, the center wavelength shift or the polarization
dependent loss of a demultiplexer. If your instrument has Option 009 installed,
it contains a built-in polarizer.
Increasing wavelength accuracy
When measuring deep-notch filters, increased absolute wavelength accuracy
may be required. To increase wavelength accuracy, the combination of an
Agilent 8168E/F tunable laser source and the Agilent 86120A multi-wave-
length meter can be used to calibrate the optical spectrum analyzer. Simply
enter the difference between the two wavelength readings (optical spectrum
analyzer and multi-wavelength meter) into the optical spectrum analyzer as a
correction factor. Refer to the user's guide for the optical spectrum analyzer to
learn how to enter correction factors. If you use this technique, be aware that
the Agilent 8168E/F measures wavelength in a vacuum and the optical spec-
trum analyzer measures wavelength in air unless you change its settings.

Performing Stimulus-Response Measurements

Making Measurements
2-3