JPH0440165Y2 - - Google Patents

Description

[Detailed explanation of the idea]

B. Industrial applications This invention is applicable to optical fiber wires wound around a bobbin, especially low loss when wound around a bobbin, and in the case of polarization-maintaining optical fiber wires, it has good polarization characteristics, such as remote measurement. The present invention relates to an optical fiber coil that is effective for signal transmission in applications such as sensor coils for optical fiber gyros. B. Prior Art When various quantities are measured remotely, signals detected at a detection end are transmitted to a measuring device using an optical fiber line. With portable or mobile measuring instruments that detect quantities in many places, the distance between the detection end and the measuring instrument varies depending on the situation, so a coil wound around a bobbin is used as the optical fiber wire, and the optical fiber wire is fed out. The detection end and measuring device are connected. In this case, conventionally, a bobbin-wound optical fiber coil in which optical fiber wires are simply wound randomly around a bobbin has been used. C. Problems that the invention aims to solve However, when long optical fiber wires are randomly wound around a bobbin, there are many parts where the optical fiber wires intersect with each other in the second and subsequent layers from the inside. During this period, the upper optical fiber line may cave in. In this case, the optical fiber bends and the transmission loss increases significantly due to the influence of microbending, and in the case of polarization-maintaining optical fiber with anisotropic stress applied to the cladding, random damage due to microbending occurs. This has the disadvantage that stress is added to the cladding and the polarization preservation properties are significantly degraded. This effect becomes more pronounced as the outer diameter of the optical fiber becomes smaller. Furthermore, crosstalk increases due to the above-mentioned crossing of the optical fiber lines. If the transmission loss and polarization preservation characteristics of the optical fiber deteriorate in this way, the performance of the optical fiber will deteriorate when used for signal transmission or optical fiber ironing. The object of this invention is to provide a bobbin-wound optical fiber coil that eliminates the above-mentioned drawbacks and does not impair the original performance of the optical fiber wire. D. Structure of the invention The present invention will be explained below with reference to the drawings. The optical fiber coil of the present invention is an optical fiber coil in which a polarization-maintaining optical fiber wire 2 is wound around a bobbin 1 with a spacer 3 interposed between each layer, as shown in FIG. As the spacer 3, thin paper, thin plastic tape, etc. can be used. In this way, even if there is unevenness due to irregular winding of the optical fiber in the lower layer, the optical fiber in the next layer will not be wound directly on top of it, but on the surface smoothed by the spacer, so that micro Abnormal deformation of the optical fiber due to bending, fiber depression, etc. can be prevented. As a result, it is possible to prevent the increase in loss caused by the deformation of the optical fiber, and in the case of polarization preserving optical fiber in particular, it is possible to suppress the generation of non-uniform external stress due to the deformation of the optical fiber. This is effective in preventing talk from occurring. In this way, a polarization-maintaining optical fiber coil that maintains its original performance is realized. E Example Polarization maintaining optical fiber with core diameter of 5 μm and cladding diameter of 125 μm, outermost diameter including coating is 240 μm

[Table] This result shows that the performance of the optical fiber wire wound on a bobbin as in the present invention can be maintained well. F. Effects of the Invention As explained in detail above, the bobbin-wound optical fiber coil of the present invention improves the transmission characteristics of the polarization-maintaining optical fiber wire by simply providing a spacer between each layer of the optical fiber wire wound during bobbin winding. The present invention is very effective because it can maintain the temperature and prevent crosstalk, and as a result, the performance of the gyroscope is greatly improved, especially when used as a sensor coil for an optical fiber gyroscope.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the bobbin-wound optical fiber coil of the present invention. 1...Bobbin, 2...Optical fiber wire, 3...
spacer.

Claims (1)

[Claims for Utility Model Registration] 1. In a bobbin-wound optical fiber coil in which polarization-maintaining optical fiber wire is wound in multiple layers, a thin tape-shaped spacer is inserted between each layer of the polarization-maintaining optical fiber wire wound around the bobbin. A bobbin-wound optical fiber coil that is characterized by: 2. The bobbin-wound optical fiber coil according to claim 1, wherein the spacer is made of thin paper.