Modified Expression for Spatial Resolution in Optical Correlation-Domain Reflectometry

Optical correlation-domain reflectometry (OCDR) is a technique used to detect faulty connections and splices in a fiber under test (FUT). Several simple configurations have been developed to reduce the size of the experimental setup. However, the theoretical spatial resolutions calculated by the original theory on standard OCDR do not agree with the experimental values obtained by simplified OCDR (S-OCDR). In this article, to clarify the cause of the inconsistency between the theoretical and measured spatial resolutions in S-OCDR, we newly establish a comprehensive theory for both standard and S-OCDR systems using the concept of the “beat spectrum,” which is primarily used in theoretical studies for Brillouin OCDR/analysis (BOCDR/A). In addition, we derive a modified expression for the spatial resolution; this highlights a tradeoff relationship between spatial resolution and measurement range, which is a well-known property for BOCDR/A but has not been previously reported for OCDR.