MOGlabs MWM, Manual, Page: 47 / 96

6.1 Existing wavelength range
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If more than four calibration points have been entered, then press the
OK
button to calculate the full cubic calibration function. If three or two
points are entered, the calibration will be limited to a quadratic or linear
function.
NOTE
It is important that the calibration wavelengths extend over the largest
possible fraction of the operating range of the wavemeter. If you cannot
tune your calibration source across a large range, use lower fit order (see
below), or single-point calibration.
If the wavelength range of entered calibration points is less than half the
full range, a new dialog will open, allowing adjustment of the fit order.
Choose the highest order for best accuracy within the range of calibration
data, or a lower order for better stability outside the calibration range.
For example, a typical
MWM
is calibrated for 775 nm to 796 nm; a range of
22 nm. That device might then be re-calibrated over a limited range such
as 775 nm to 780 nm. If a cubic fit order is selected, the accuracy will be
best within that range of 775 to 785 nm but can be very poor outside that
range. A lower fit order, such as quadratic, will be more stable across the