Hewlett-packard Company

Josef Beller

Peter Thoma

Disclosed is a system for determining wavelength dependent information, preferably event loss, reflectance, center wavelength, cross talk, directivity, and/or isolation, about an optical component in an optical structure. The system includes at least one light emitting source for providing light signals at a plurality of different wavelengths to an optical link which is in an optical connection with the optical component, a measuring unit for measuring a backscattered and/or reflected signal versus time returning from the optical structure, and a processing unit for determining the wavelength dependent information about the optical component by processing the measured signal versus time as measured for a plurality of light signals at different wavelengths. A particularly advantageous application of the invention is to determine the wavelength dependent spatial structure of an optical network. In that case, the wavelength dependent information is associated with spatial information representing spatial properties of the optical component.

Remote measurement of wavelength dependent information about optical

This invention relates to a method and an apparatus for performing exceptionally linear averaging of digitized signals in an optical time domain reflectometer. Resolutions far below the quantization level of the ADC with improved linearity can be achieved without sacrificing dynamic range. Such method can be used to improve measurement accuracy on optical fibers under test.

Optical time domain reflectometer (OTDR) with improved dynamic range and

In a method and a corresponding apparatus for performing optical time domain reflectometry predetermined time sequences of light signals (A', B') are injected into an optical fiber and the signals backscattered from the fiber are correlated with the injected sequences. The injected time sequences are selected according to a specific code such that after each element in the code represented by '1' or '-1', a predetermined number of elements represented by '0' is provided. Depending on the number of inserted '0's after each '1' or '-1', sidelobes in the correlation product appear at certain predictable positions. By choosing the numbers of inserted '0's differently for different injections, the resulting sidelobes appear at different positions in the corresponding correlation products. From the correlation products of such different injections, a composite fiber response can be derived wherein sidelobes are substantially eliminated. The codes used can be derived, for example, from Golay complementary codes.

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Hildrizhausen, Germany

Josef Beller