Absolute distance measurements based on TD SM-SLD: performances characterization and calibration

Time-Domain Low-Coherence Interferometry (TD-LCI) is a well-known optical method to perform absolute distance measurements. As an alternative to conventional TD-LCI, the Self-Mixing Super Luminescent Diode (SM-SLD) technique represents a unique approach for simplicity and compactness. The presence of optical feedback in the source cavity allows obtaining huge interference fringes, even with diffusive targets and without using high-sensitivity and low-noise detectors. In this work, we present the performances of a custom-made SM-SLD interferometer for absolute distance measurements compared with a reference incremental interferometer. Thanks to the simplified acquisition method and the resulting improved signal-to-noise ratio, the system exhibits excellent metrological performances.