  Manipulation of the detected backscattered Rayleigh signal inside the
bandwidth of a frequency-swept optical sub-carrier propagating into an optical
fiber permits an efficient localization of faults through a Fourier operator.
When the bandwidth is restricted, analysis in the frequency domain can overcome
the spatial resolution limitation while also inducing a high-dimensional
problem. Introducing the Lasso as a signal processing technique paired with the
Baseband Subcarrier Sweep (BSS) framework allows for a methodology to
consistently evaluate fiber defects. In this work, a novel technique for
optical fiber monitoring within the BSS framework, hereinafter called the
BSS-Lasso, is proposed and tested in simulated and real-world environments,
taking into account both reflective and non-reflective events. The results show
that, for fiber links ranging from 2 to 15 km with up to 3 faults, over 80% of
faults are detected within a 50 m range, and indicate that the proposed
methodology significantly outperforms current state-of-the-art BSS-based
supervision techniques. Finally, the BSS-Lasso allows for precise, low-cost,
transmitter-embedded full characterization of optical fiber links.
