User`s guide

Wavelength Accuracy Performance Tests
Agilent 81600B Tunable Laser Source Family, Fourth Edition 81
Smallest Minimum Deviation subracted from the
Largest Maximum Deviation.
13 Determine, and note in the Test Record, the
Absolute Wavelength Accuracy, which is the largest deviation (of
either the Smallest Minimum Deviation or the Largest Maximum
Deviation).
Mode-Hop Free Tuning
For definition, see “Mode-hop free tunability” on page 41.
Measurement Principle
The mode-hop free sweeping range (= mode-hop free span) is defined for
the sweep mode. The sweep mode operates without TCFS. A mode-hop is
an abrupt change of the laser wavelength during tuning, when the laser
changes to another longitudinal mode. In the mode-hop free sweeping
range, abrupt changes of the wavelength larger than 25 pm are not
allowed. To test this, the wavelength of the TLS is continuously swept over
the tuning range and the wavelengths are measured by the TCFS. The
difference between two successive wavelengths should not deviate more
than 25 pm from the ratio of the scan range to the number of wavelength
reading points. The test of the mode-hop free sweeping range requires
dedicated software and cannot be done manually. Agilent Technologies
service centers use this software to test the TLS for mode-hop free
sweeping.
Figure 21 Mode-hop free Tuning Range.