My measured spectrum of the oscillator looks very different from the one shown on the certificate of conformity. Why has this happened?

Measuring broad spectra as they are emitted by the venteon oscillator series requires an intensity calibrated spectrometer. The typical compact CCD spectrometer is not intensity calibrated, meaning that portions of spectrum are displayed differently from a measurement using a calibrated instrument. This is especially true for the long wavelength edge above 1000nm, which will be largely underestimated by non-calibrated spectrometers.

High accuracy intensity calibrated spectrometers include; the Ando AQ6317B, or the Yokogawa AQ6370.

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