Coherent has developed a system using paired OTDRs to characterize optical fiber spans, doubling measurement capabilities. By combining OTDR traces, the system accurately determines optical path length, signal loss, and chromatic dispersion. This innovative technology enhances fiber network monitoring and maintenance efficiency. GlobalData’s report on Coherent gives a 360-degree view of the company including its patenting strategy. Buy the report here.

According to GlobalData’s company profile on Coherent, Lithium-ion batteries was a key innovation area identified from patents. Coherent's grant share as of January 2024 was 68%. Grant share is based on the ratio of number of grants to total number of patents.

Optical fiber span characterization system using paired otdrs

Source: United States Patent and Trademark Office (USPTO). Credit: Coherent Corp

A recently granted patent (Publication Number: US11885707B2) discloses a system for characterizing an optical fiber span between two nodes using optical time domain reflectometers (OTDRs) at both ends. The system includes a near-end OTDR and a far-end OTDR, each equipped with a light source, a receive component, and a processing module to generate OTDR traces. A characterization element combines the near-end and far-end OTDR traces to create an end-to-end OTDR trace, estimating optical path length and signal loss to determine a mid-point for trace-stitching. The system utilizes a time-of-flight technique and optical power loss measurements to estimate these parameters accurately.

Furthermore, the system incorporates a multi-wavelength light source at the near-end, allowing for wavelength-dependent measurements of optical path length and power loss. The characterization element records these measurements for each wavelength, providing valuable data for determining chromatic dispersion and Raman gain profiles of the optical fiber span. Additionally, the system includes an adjustable polarization controller at the near-end to change the state of polarization of the optical probe over time, enabling the characterization element to assess polarization-dependent loss. Overall, the system and method described in the patent offer a comprehensive approach to characterizing optical fiber spans, enhancing the understanding of their performance and potential issues.

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