JPH08313272A - Method for winding fiber-optic coil and fiber-optic coil formed by the method - Google Patents

Abstract

PURPOSE: To offset performance deterioration to temperatures, eliminate winding irregularities thereby to improve workability and wind an optical fiber to have a length as approximate as possible to a required length, by winding the optical fiber by a combination of a plurality of kinds of winding methods different in a unit count of layers. CONSTITUTION: According to the winding method for an optical fiber, a count of layers (n) at the preceding winding time is made larger than a count of layers (n) at the succeeding time. The count of layers (n) is 2P (P is a positive integer). The count of layers at the final winding time is 2. For instance, the optical fiber is wound by setting a unit count of layers to offset performance deterioration by a change of an environmental temperature to be 8. An area denoted by W1 is where the optical fiber is wound by setting the unit count of layers (n) to offset the performance deterioration to be 8. An area W2 is where the optical fiber is wound by setting the unit count of layers (n) to offset the performance deterioration to be 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber coil winding method and an optical fiber coil formed by this method, and more particularly to an optical fiber having a length which approximates a required optical fiber length with a small error. The present invention relates to an optical fiber coil winding method wound by a winding method that cancels performance deterioration due to a change in environmental temperature, and an optical fiber coil formed by this method.

[0002]

2. Description of the Related Art A conventional example of an optical fiber gyro will be described with reference to FIG. In FIG. 2, the light emitted from the light source 1 passes through the optical directional coupler 2, the polarizer 3, and the optical directional coupler 4 to form an optical fiber coil 6 forming a sensing coil.
It is sent in as clockwise light and counterclockwise light. The right-handed light is first phase-modulated in the phase modulator 5 from the point B, and the phase-modulated right-handed light is sequentially passed through the optical directional coupler 4, the polarizer 3, and the optical directional coupler 2. Reach the light receiver 7. Similarly, the counterclockwise light is first phase-modulated in the phase modulator 5 from the point A, and the phase-modulated counterclockwise light sequentially passes through the optical directional coupler 4, the polarizer 3, and the optical directional coupler 2. It reaches the light receiver 7 via. The phase-modulated light that has reached the light receiver 7 is photoelectrically converted into an electric signal here. The electric signal photoelectrically converted by the light receiver 7 is input to the synchronous detector 8. In the synchronous detector 8,
Using the signal supplied from the oscillator 9 as a reference signal, the fundamental wave component 13 that is an angular velocity output proportional to the angular velocity of rotation of the optical fiber coil 6 around the central axis can be obtained.

Now, a method of winding an optical fiber coil for canceling performance deterioration due to a change in environmental temperature will be briefly described with reference to FIG. As described above, the optical fiber gyro makes light incident on the optical fiber coil 6 from both points A and B, propagates the light in the directions of point B → point A and point A → point B, and propagates both the propagated lights. Each input velocity is measured from the change in the light intensity caused by the interference.

Now, even though the optical fiber gyro is in a stationary state in which there are no input velocities, a temperature change occurs at a certain point inside the optical fiber coil 6, and due to this temperature change, the temperature changes at that point. When the physical and optical characteristics change, a difference occurs in the propagation speed of light between the path from point B to point A and the path from point A to point B, and the interference light intensity changes. That is, although the optical fiber gyro is actually in a stationary state, each input speed is apparently present.

In order to suppress such inconvenience, it is assumed that points A and B of the optical fiber are equidistant from the center point C of the optical fiber, and point A is equidistant from the center point C. If the optical fiber is wound so that the point B and the point B are subjected to the same temperature change, the light propagation speed is also subjected to the same change, and the influence of the temperature change is offset. That is, in FIG. 3B, the winding is performed with l ₁ = l ₂ .

This will be specifically described with reference to FIG. First, the optical fiber on the side of the point A from the center point C of the optical fiber is wound into one layer. Next, the optical fiber on the point B side is wound into two layers. Then, the optical fiber on the side of the point B is wound back into three layers by turning back, and the optical fiber on the side of the last point A is wound into four layers. The fiber length of each of the 1, 2, 3, and 4 layers is different because the diameter increases for each layer, but 1, 4 layers on the A side and 2 or 3 layers on the B side are used. Thus, the integrated length of the A-side fiber and the integrated length of the B-side fiber are equal. By winding in this way, the corresponding 1st layer and 2nd layer occupy the positions which mutually approach in the inside of the optical fiber coil 6, and the corresponding 3rd layer and 4th layer mutually in the inside of the optical fiber coil 6. They occupy positions that are close to each other, and are thermally affected by the same effect, resulting in the above-mentioned canceling effect.

In FIG. 3 (c), an optical fiber winding method is employed in which the optical fiber coil 6 is wound around the winding frame 20 in units of four layers each to cancel the performance deterioration due to the change in the ambient temperature. There is. The number of layers means the number of laminated optical fibers in the radial direction of the winding frame 20 when the optical fiber is wound around the winding frame 20.

[0008]

Here, referring to FIG. 1, the axial length of the bobbin 20 is H, the radial winding allowance is W, the average diameter is D _AV , and it is necessary to set a target. The optical fiber length is L, and the optical fiber having the diameter d is wound around the winding frame 20. The winding method is the same as the method illustrated and described with reference to FIG. s is the winding start portion of the optical fiber, and e is the winding end portion of the optical fiber.

When a winding method is used in which the deterioration of performance due to a change in environmental temperature is offset as one unit of n layers, the number of turns N _{T in the} axial direction is the maximum value of natural numbers satisfying N _T ≤H / d.

In this case, the number of radial layers N _l is the maximum value that satisfies the two equations of π × D _AV × N _T × N _l ≤L N _l = kn k: natural number. A winding method in which the number of layers in one unit that cancels the performance deterioration due to the change in the environmental temperature is n = 8 will be specifically described.

N _l ≦ L / (π × D _AV × N _T ) N _l = 8k Here, when the integer part on the right side of the equation is (8t + S), it becomes a fraction for the S layer and is wound. If this is not done, it means that the required number of turns is insufficient for the required fiber length L.

However, t: natural number indicating the number of units S: natural number of 1 to 7 indicating the number of layers This insufficient fiber length ΔL is ΔL = π × D _AV × N _T × S.

The occurrence of the deficiency ΔL with respect to the required fiber length L means that the performance of the optical fiber coil originally estimated by the winding method for canceling the performance deterioration due to the change of the environmental temperature is sacrificed. . D _AV = 100 mm,
When N _T = 100 and S = 7, ΔL = 220 m, and the performance cannot be maintained.

The number of layers in one unit for canceling the performance deterioration is n = 2.
Then, although it is improved to ΔL = 31 m, the winding procedure is complicated because the winding work is canceled by all the two layers, and the number of crossing the optical fibers increases during the winding process. Disturbance occurs. As described above, it is disadvantageous in view of both workability and performance maintenance to set the minimum number of layers of 1 unit that cancels performance deterioration to n = 2.

It is possible to physically satisfy the required fiber length L by winding the fractional S layer ignoring the canceling effect. However, since the effect of canceling the performance deterioration does not act on this portion, it becomes the main cause of the performance deterioration when the environmental temperature changes. According to the present invention, the length of the fiber to be actually wound is approximated to the required fiber length as much as possible, the deterioration of the performance of the optical fiber coil due to the temperature change is offset, the winding disorder is suppressed as much as possible, and the winding with good workability is attempted. To do.

[0016]

In an optical fiber coil winding method for canceling performance deterioration due to a change in environmental temperature by winding an optical fiber 6 with n layers as one unit,
An optical fiber coil winding method for winding an optical fiber is configured by combining a plurality of types of winding methods with different number of layers n as one unit.

Then, an optical fiber coil winding method is constituted in which the number of layers n in the previous winding is made larger than the number of layers n in the subsequent winding. The number of layers n is 2 ^P (P: positive integer), and the optical fiber coil winding method is configured. Further, the number of layers n in the previous winding is made larger than the number n of layers in the subsequent winding, and the number of layers n is 2 ^P (P: a positive integer).

Then, an optical fiber coil winding method in which the number of layers in the final winding is 2 was constructed. Here, an optical fiber coil formed by the above-described optical fiber coil winding method was constructed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be concretely described with reference to FIG. First, the number of layers of one unit that cancels the performance deterioration due to the change of the environmental temperature is set to n = 8, and winding is performed. w ₁
The area indicated by is an area in which the optical fiber is wound with the number of layers of one unit for canceling the performance deterioration being n = 8.

When n = 8, N _l ≤L / (π × D _AV × N _T ) N _l = 8k. Here, when the integer part on the right side of the equation is 8t + S, for the optical fiber length of S layers which is insufficient for the required optical fiber length L, the number of layers of 1 unit that cancels the performance deterioration is set to n = 2. Apply the winding method. The region indicated by w ₂ is a region in which the optical fiber is wound with n = 2 as the number of layers of one unit that cancels the performance deterioration.

When n = 2 is implemented, the number m of layers that can be wound with n = 2 is S = 2m + 1 (m: 0, natural number).
Becomes Since S = 1 to 7, when m = 3, the fiber length is one layer less than L, and ΔL = 31 m. This ΔL is n = 2 from the beginning of the required optical fiber length L.
Is the same as ΔL when wound as. However, n =
It is preferable to start winding as 8 and then to set n = 2 for the fractional S as compared with the case where all necessary optical fiber lengths L are set to n = 2 and set n = 2. Since the number of layers to be wound is small, winding disorder is reduced and workability is also reduced.

Deterioration of performance due to changes in ambient temperature is reduced to 1 in n layers.
When a winding method that cancels out by winding as a unit is adopted, by combining a plurality of types of winding methods with different number of layers n as one unit, performance deterioration due to environmental temperature change Offsetting, and poor workability,
Performance deterioration due to winding disorder can be reduced, and an optical fiber having a length close to the required fiber length can be wound, and an optical fiber coil exhibiting performance as designed can be constructed.

In the above embodiment, the number of layers for one unit is n =
In this example, the winding methods of 8 and n = 2 are combined.
The present invention can be implemented with a combination of the number of layers n other than this. For example, n = 8, n =
4, the optical fiber coil can be configured with n = 2. When an optical fiber is wound by combining a plurality of types of winding methods with different number of layers n as one unit, generally,
It is preferable that the number of layers n in the previous winding is made larger than the number of layers n in the subsequent winding, and the number of layers n is 2 ^P (P: positive integer). And if the number of layers in the last winding is 2,
The number of layers that becomes a fraction can be reduced.

[0024]

As described above, the present invention cancels the performance deterioration with respect to temperature by combining several kinds of winding methods having a canceling effect in a plurality of layers against a temperature change,
It is possible to construct an optical fiber coil that can perform the designed performance by canceling the poor workability and performance deterioration due to winding disorder, and winding the optical fiber length as close as possible to the required fiber length. .

[Brief description of drawings]

FIG. 1 is a diagram illustrating a winding method of an optical fiber coil according to the present invention.

FIG. 2 is a diagram illustrating a conventional example of an optical fiber gyro.

FIG. 3 is a diagram illustrating a winding method for canceling performance deterioration.

[Explanation of symbols]

6 optical fiber 20 winding frame s winding start part e winding end part w ₁ area where the optical fiber is wound as n = 8 area where the optical fiber is wound as w ₂ n = 2

Claims (10)

[Claims] 1. An optical fiber coil winding method for canceling performance deterioration due to a change in environmental temperature by winding an optical fiber with n layers as one unit, and a plurality of types with one layer being different in the number n of layers. An optical fiber coil winding method, characterized in that an optical fiber is wound by combining the winding methods of. 2. The optical fiber coil winding method according to claim 1, wherein the number of layers n in the previous winding is larger than the number of layers n in the subsequent winding. Method. 3. The optical fiber coil winding method according to claim 1, wherein the number of layers n is 2 ^P (P: positive integer). 4. The optical fiber coil winding method according to claim 1, wherein the number of layers n in the previous winding is made larger than the number of layers n in the subsequent winding, and the number of layers n is 2.
An optical fiber coil winding method, wherein ^P (P: positive integer). 5. The optical fiber coil winding method according to any one of claims 1 to 4, wherein the number of layers in the last winding is two. Method. 6. An optical fiber coil for canceling performance deterioration due to a change in environmental temperature by winding an optical fiber with n layers as one unit, and a plurality of optical fibers having different number of layers n as one unit. An optical fiber coil characterized by being constructed by winding. 7. The optical fiber coil according to claim 6, wherein the number of layers n in the previous winding is larger than the number n of layers in the subsequent winding. 8. The optical fiber coil according to claim 6.
In, the number of layers n is 2 ^P(P: positive integer)
Characteristic optical fiber coil. 9. The optical fiber coil according to claim 6, wherein the number of layers n in the previous winding is made larger than the number of layers n in the subsequent winding, and the number of layers n is 2 ^P (P: positive). (Integer) is an optical fiber coil. 10. The optical fiber coil according to any one of claims 6 to 9, wherein the number of layers in the last winding is two.