Swept Wavelength Testing:

In a swept-wavelength measurement system, the wavelength of a tunable laser source (TLS) is swept continuously at a constant rate throughout the desired tuning range, while the device under test (DUT) is monitored simultaneously for its wavelength-dependent optical properties. Given an ideal continuously tunable laser – one that does not exhibit any discontinuities in wavelength, or sudden changes in direction – you can calculate the instantaneous wavelength and relate each wavelength point to data from the DUT. Because the wavelength is computed by using the sweep speed and elapsed time from the beginning of the sweep, the measured tuning linearity of the laser has a direct impact on the wavelength accuracy.