Optics: measuring and testing – For optical fiber or waveguide inspection
Reexamination Certificate
2000-01-26
2002-09-24
Font, Frank G. (Department: 2877)
Optics: measuring and testing
For optical fiber or waveguide inspection
C385S116000
Reexamination Certificate
active
06456369
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a multi-core optical fiber inspecting method and apparatus, and more particularly, to a multi-core optical fiber inspecting method and apparatus for confirming the coincidence between the alignment order of input-side cores of a multi-core optical fiber and the alignment order of output-side cores of the multi-core optical fiber for use as an optical communication medium, and for measuring a transmission loss of each core in one step.
2. Description of the Related Art
A multi-core optical fiber is prepared by aligning a plurality of optical fiber cores in the form of a tape in one plane. In the case of such a multi-core optical fiber, the alignment order of input-side cores is required to coincide with the alignment order of output-side cores Supposing that the alignment order of input-side cores is not coincident with the alignment order of output-side cores, it would be impossible to transmit optical signals to any target transmission line. However, the coincidence between the input and output core numbers needs confirming because nonconforming multi-core optical fibers in which the alignment order of input-side cores is not coincident with the alignment order of output-side cores are produced sometime during the process of manufacturing multi-core optical fibers.
In order to improve the production efficiency of multi-core optical fibers, moreover, it has also been required to measure the transmission loss of the optical fiber as its basic characteristic quickly without troublesome work.
A conventional method of verifying core numbers of multi-core optical fibers will be described with reference to
FIG. 14
In
FIG. 14
, reference numeral
1100
denotes a light source;
1102
, a multi-core optical fiber; and
1104
, an optical power meter.
When core numbers of multi-core optical fibers are verified and when the transmission loss thereof is measured, the optical power meter
1104
has heretofore been used to measure output light from the emission end of each core of the multi-core optical fiber
1102
by putting the output of the light source
1100
into the incident end core of the multi-core optical fiber
1102
. For example, the optical output of the light source
1100
is put into the incident end of No. 1 core, whereupon the optical power meter
1104
is used to verify the power of the optical signal that is output from the emission end of the No.1 core.
In the conventional methods of verifying core numbers of multi-core optical fibers, one output end of the multi-core optical fiber
1102
is split into single cores, which are separately connected to the optical power meter
1104
for measuring purposes. Consequently, much time has been required to take an accurate measurement as extremely complicated preparations for such the measurement are needed. Moreover, there has been the possibility of making errors in verifying core numbers because the optical output of each core is measured by switching the connections between the light source and the input-side cores.
SUMMARY OF THE INVENTION
An object of the present invention made under the circumstances stated above is to provide a multi-core optical fiber inspecting method and apparatus for confirming the coincidence between the alignment order of input-side cores of a multi-core optical fiber and the alignment order of output-side cores of the multi-core optical fiber and for measuring the transmission loss of the optical fiber as its basic characteristic simply, quickly and accurately in one step.
In order to accomplish the object above, according to a first aspect of the present invention, there is provided a multi-core optical fiber inspecting method comprising the steps of putting an optical signal into each incident end core of a multi-core optical fiber having a plurality of cores arranged in one plane, taking out the optical signal emitted from the emission end of the core in a time series mode according to the alignment order of emission-side cores of the multi-core optical fiber, and verifying core numbers of the respective cores of the optical fiber on the basis of the signal patterns thus taken out in the time series mode. Therefore, the coincidence between the alignment order of the input-side cores of the multi-core optical fiber and the alignment order of the output-side cores thereof can be confirmed simply, quickly and accurately.
According to a second aspect of the present invention, when the core numbers of the respective cores of the multi-core optical fiber are verified, the power of each of the optical signals put into and emitted from the multi-core optical fiber is measured thereby to measure the transmission loss of the multi-core optical fiber. It is therefore possible to confirm the coincidence between the alignment order of the input-side cores of the multi-core optical fiber and the alignment order of the output-side cores thereof and to measure the transmission loss of the optical fiber as its basic characteristic in one step simply, quickly and accurately.
According to a third aspect of the present invention, there is provided a multi-core optical fiber inspecting apparatus, in which the multi-core optical fiber having the plurality of cores arranged in one plane, comprising: the light source having the plurality of optical output terminals which are connected to the incident ends of the respective cores of the multi-core optical fiber and used for putting optical signals into the respective cores thereof; the optical signal taking means for taking out the optical signal emitted from the emission end of each core of the multi-core optical fiber in the time series mode according to the alignment order of emission-side cores of the multi-core optical fiber; the optical signal detecting means for detecting the optical signal thus taken out by the optical signal taking means; and the signal processing means for verifying core numbers of the respective cores of the multi-core optical fiber on the basis of the signal patterns of detection outputs of the optical signal detecting means. Therefore, the coincidence between the alignment order of the input-side cores of the multi-core optical fiber and the alignment order of the output-side cores thereof can be confirmed simply, quickly and accurately.
According to a fourth aspect of the present invention, in the multi-core optical fiber inspecting apparatus of the third aspect of the present invention, the optical signal taking means has the rotary plate formed with the opening of a size large enough to totally let pass all the optical signals emitted from the respective cores of the multi-core optical fiber, and the optical signal detecting means includes the light receiving element having an area large enough to collectively receive all the optical signals emitted from the respective cores of the multi-core optical fiber. It is therefore possible to confirm the coincidence between the alignment order of the input-side cores of the multi-core optical fiber and the alignment order of the output-side cores thereof and to measure the transmission loss of the optical fiber as its basic characteristic in one step simply, quickly and accurately.
According to a fifth aspect of the present invention, there is provided a multi-core optical fiber inspecting apparatus, in which the multi-core optical fiber having the plurality of cores arranged in one plane, comprising: the multi-output light source unit having the plurality of optical output terminals which are connected to the incident ends of the respective cores of the multi-core optical fiber and used for putting optical signals into the respective cores thereof; the rotary plate having at least one slit which is driven to rotate in such a way as to cross the optical beam emitted from the emission end of each core of the multi-core optical fiber; the optical signal detecting means for detecting the optical signal emitted from the emission end of each core of the multi-core optical fiber as the time series signal according to th
Iida Rikihiro
Ohki Kazuhiro
Ando Electric Co. Ltd.
Fish & Richardson P.C.
Font Frank G.
Nguyen Tu T.
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