User`s guide

Wavelength Accuracy Performance Tests
Agilent 81600B Tunable Laser Source Family, Fourth Edition 77
Wavelength Accuracy
The procedures in this section show how to calculate the Relative
Wavelength Accuracy, Absolute Wavelength Accuracy, Mode-hop Free
Tuning, and Wavelength Repeatability results.
Absolute and Relative Wavelength
Accuracy
For definitions, see:
“Absolute wavelength accuracy (continuous sweep mode)” and “Absolute
wavelength accuracy (stepped mode)” on page 37;
“Relative wavelength accuracy (continuous sweep mode)” and “Relative
wavelength accuracy (stepped mode)” on page 45.
Measurement Principle
The TLS is set to certain wavelengths and the actual wavelength is
measured using a well-calibrated wavelength meter. Ideally, the displayed
and measured wavelengths should coincide. The difference between the
displayed and measured (actual) wavelength is the Absolute Wavelength
Accuracy.
Relative Wavelength Accuracy describes the instrument's ability to
generate precise wavelength steps. For example, if the wavelength setting
is changed by 1 nm, the actual wavelength should change by 1 nm. To test
for deviations from this ideal, the tunable laser source is set to various
wavelengths, and the actual wavelength is measured using a wavelength
meter.
The measurement of the relative wavelength accuracy includes the
measurement of absolute wavelength accuracy. The absolute wavelength
accuracy measurement program generates all the results needed for the
calculation of the relative wavelength accuracy.