A laser unit has a laser mode selection and provides a laser signal in accordance
to a laser control parameter. A plurality of pairs of values is determined for
the laser control parameter and a laser operation parameter indicative of the laser
unit's operation to provide the laser signal. A target operating point for the
laser unit is derived from the determined pairs of values in conjunction with a
model and a selection criterion for selecting the target operating point, wherein
the model represents an assumed relationship between the laser control parameter
and the laser operation parameter. A curve for the relationship between the laser
control parameter and the laser operation parameter is approximated based on the
determined pairs of values in conjunction with the model, the curve limited on
at least one side having a defined boundary in a range where mode hopping is likely,
and the target operating point selected on the approximated curve based on the
selection criterion.