A tunable laser platform may offer several wavelength-band variants. A broad portfolio range does not mean that every unit covers the full range. Identify the required start and stop wavelengths before comparing product types.
Separate wavelength resolution, accuracy, repeatability and linewidth. Ask which values apply during a sweep and which require a stationary wavelength or a particular coherence setting. Record output power versus wavelength rather than treating a peak value as a guarantee across the band.
Define the intended measurement, optical interfaces, detector, polarisation control and synchronisation method. Use the model-specific documentation to set the acquisition plan and retain its operating conditions with the results.