Lios Technology Gmbh

Nkt Photonics A/s

Martin Fromme

Wieland Hill

Jochen Kübler

Friedhelm Kurtscheid

Ingo Roda

Ulrich Glombitza

Jochen Kuebler

Fiber-optic cable useful in a borehole is provided, with at least one optical waveguide (), at least one metallic tube () which at least partially surrounds the at least one optical waveguide (), and at least one additional layer, which at least partially surrounds the at least one metallic tube (). The fiber-optic cable includes a separator which contributes to or cause mechanical decoupling of individual components of the fiber-optic cable.

Fiber-optic cable

A device for spatially resolved measuring of a physical variable has a device for generating a first electrical signal with a first frequency and a device for generating a second electrical signal with a second frequency. The second frequency differs from the first frequency by a difference frequency. An optical radiation source generates an optical signal modulated by the first frequency. The optical signal can interact with a test object and be modified in the process. A mixer can mix an electrical signal emerging from the optical signal with the second signal. A device, particularly embodied as a DDS system, generates a third electrical signal with a third frequency that corresponds to the difference frequency or a multiple of the difference frequency. A digital/analog converter digitizes the at least one mixed signal by sampling the mixed signal at the third frequency in order to digitize it.

Method and apparatus for the spatially resolved measurement of a physical variable

A device for calibrating a fiber-optic temperature measuring system has a broadband light source, a coupling-in device, which can couple light generated by the light source for calibration into an optical fiber of the temperature measuring system, a coupling-out device, which can couple components of the light source-generated light that are backscattered in the optical fiber out of the optical fiber. An evaluation device performs a calibration of the temperature measuring system on the basis of the backscattered components of the light.

Device and method for calibrating a fiber-optic temperature measuring system

The object of the invention is to provide a method of calibrating an optical FMCW backscattering measurement system that improves the precision of the measurement. The problem is solved by a method comprising the steps of A. Converting said received sensor signal to a complex received electrical signal as a function of said modulation frequency fm, said complex received electrical signal being represented by a magnitude part and a phase angle part as a function of said modulation frequency fm; B. Performing a transformation of said received electrical signal to provide a backscattering signal as a function of location between said first and second ends of said sensor and beyond said second end; C. From said backscattering signal as a function of location determining characteristics of a curve representative of said backscattering signal beyond said second end; D. Correcting said magnitude part of said received electrical signal and said phase angle part of said received electrical signal in a predetermined dependence of said curve; and E. Repeating step B) on the basis of the corrected received electrical signal.

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Kö'ln, Germany

Martin Fromme