The frequency-sampling method is widely used to accommodate nonlinear electromagnetic source tuning in swept-wavelength interferometric techniques, such as optical frequency domain reflectometry (OFDR) and swept-wavelength optical coherence tomography (OCT). Two sources of sampling errors are associated with the frequency-sampling method. One source of error is the limit of an underlying approximation for long interferometer path mismatches and fast electromagnetic source tuning rates. A second source of error is transmission delays in data acquisition hardware. Aspects of the invention relate to a method and system for correcting sampling errors in swept-wavelength interferometry systems such that the two error sources correct sampling errors associated with the first radiation path and the second radiation path cancel to second order.