  Supervision of the physical layer of optical networks is an extremely
relevant subject. To detect fiber faults, single-ended solutions such as the
Optical Time Domain Reflectometer (OTDR) allow for precise measurements of
fault profiles. Combining the OTDR with a signal processing approach for
high-dimensional sparse parameter estimation allows for automated and reliable
results in reduced time. In this work, a measurement system composed of a
Photon-Counting OTDR data acquisition unit and a processing unit based on a
Linearized Bregman Iterations algorithm for automatic fault finding is
proposed. An in-depth comparative study of the proposed algorithm's
fault-finding prowess in the presence of noise is presented. Characteristics
such as sensitivity, specificity, processing time, and complexity, are analysed
in simulated environments. Real-life measurements that are conducted using the
Photon-Counting OTDR subsystem for data acquisition and the Linearized
Bregman-based processing unit for automated data analysis demonstrated accurate
results. It is concluded that the proposed measurement system is particularly
well suited to the task of fault finding. The natural characteristic of the
algorithm fosters embedding the solution in digital hardware, allowing for
reduced costs and processing time.
