Optics: measuring and testing – For optical fiber or waveguide inspection
Patent
1994-08-04
1996-07-30
McGraw, Vincent P.
Optics: measuring and testing
For optical fiber or waveguide inspection
G01N 2159, G01N 2184
Patent
active
055417256
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a test device for optical waveguides using an optical receiver which exhibits a coupling device as well as a light-sensitive element disposed in the radiation field of an emission signal to be coupled out and with which an evaluating device is associated.
A test device of this type is disclosed in DE-C2-34 29 947. It permits the assessment of a splice position of an individual optical waveguide. An emission signal is injected by means of a coupling device into the optical waveguide ahead of the splice position and is coupled out, after the splice position, on the reception side by means of a second coupling device. The exit field of the coupled-out emission signal is received by a photodiode and subsequently displayed.
If a plurality of optical waveguides were inserted into this known test device, then it would be possible to measure only the common, superposed sum of the individual radiation fields of the optical waveguides. It would not be possible to draw from this superposition sum conclusions as to the selective, characteristic individual radiation fields of the inserted optical waveguides, since a functional dependence between the selective test variables and the superposed sum cannot be derived. An individual statement, for example, as to the splice attenuation of a specific optical waveguide within a test device according to the prior art is not possible.
DE-A1-39 11 429 discloses a device for aligning two fiber ends of optical waveguides in a splice position. Shadow images of the two optical waveguide ends are generated by an illumination of the two fiber ends of a single optical waveguide from outside. These two shadow images are received by at least two stationary, separate photosensitive surfaces, which are disposed along the longitudinal axis of the optical waveguide. A control variable for a positioning device for the in-line alignment of the fiber ends is derived from the separate electrical test signals generated by the photosensitive surfaces, by comparison. Statements concerning characteristic quantities describing the transmission behavior of the optical waveguide are not possible with such a device. In particular, no splice attenuation testing can be carried out in this manner.
SUMMARY OF THE INVENTION
The object of the invention is to specify a test device by means of which the characteristic quantities reproducing the transmission behavior, of a plurality of optical waveguides and/or their spatial position can be tested selectively in a simple and reliable manner.
In the case of a test device of the initially mentioned type, this object is achieved in that the coupling device is designed in such a manner that at least two optical waveguides are insertable in an ordered structure alongside one another so that they exhibit independent radiation fields lying alongside one another, in that at least one second light-sensitive element is provided, in that these at least two light-sensitive elements are disposed and aligned with respect to their reception characteristics in such a manner that they pick up different parts of said radiation fields, and in that in the evaluating device those test signals of the individual radiation fields which are recorded by the individual light-sensitive elements are separately evaluated.
The invention improves the possibilities for the selective evaluation of the received radiation fields of a plurality of optical waveguides with respect to their selective optical transmission characteristic quantities and/or spatial position. The additional expenditure required to this end, i.e. the utilization of a plurality of light-sensitive elements, does, in contrast, remain negligible. An advantage of a test device according to the invention resides especially in that, even with a single test process, a gain in test information for each individual optical waveguide or for a group of pertinent optical waveguides is achieved.
While with the known test device, with only a single light-sensitive element for n optic
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patent: 5040866 (1991-08-01), Engel
Andersen et al, "Lightwave Splicing and Connector Technology", AT&T Technical Journal, vol. 66, No. 1, Jan.-Feb. 1987, pp. 45-64.
Patent Abstracts of Japan, vol. 7, No. 42 (P177) (1187) 19 Feb. 1983 of Japanese 57-192911 (Nov. 27, 1982).
Patent Abstracts of Japan, vol. 13, No. 583 (P981) (3931) Dec. 22, 1989 of Japanese 1-246512 (Oct. 2, 1989).
Patent Abstracts of Japan, vol. 8, No. 38 (P-255) (1475) Feb. 18, 1984 of Japanese 58-191947, (Nov. 9, 1983).
Patent Abstracts of Japan, vol. 11, No. 299 (P621) (2746) Sep. 29, 1987 of Japanese 62-91832 (Apr. 27, 1987).
Lieber Winfried
Wartmann Thomas
McGraw Vincent P.
Siemens Aktiengesellschaft
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