How much can a DFB-QCL be tuned?

The operation range of the device is -30...+30C (dT=60K). The relative tuning is constant for all wavelengths and is about 6E-5/K for wavelength and -6E-5/K for wavenumber. This results in a tuning range of about 0.4% of peak emission wavelength or wavenumber.

For a 1500/cm device, the total tuning is approximately given by

${-6E-5/K \times 60K \times 1500/cm}$ i.e -5.4/cm.

Note: The relative tuning has a minus sign for wavenumbers and a positive sign for wavelength. This is exactly opposite to how a lead-salt device would tune, for those accustomed to this type of devices.