Agilent Technologies 86038B User Manual page 296

If sweeps occur with more serious laser instabilities, the
measurement will be cancelled. This may indicate conditions
under which the laser cannot correctly operate or that it needs
realignment or repair. If it is desired to allow such
measurements to complete despite the instability, this can be
chosen from the System>Config menu.
296
Agilent 86038B Photonic Dispersion and Loss Analyzer, Second Edition