JPH0664211U - Optical fiber and polarization maintaining fiber wound polarizer using the same - Google Patents

Abstract

(57) [Summary] [Structure] The jacket sheath 12 of the optical fiber 1 is provided with a copying section 12A that follows the winding surface of the winding body while the twist of the optical transmission section 11 is restricted. [Effect] Not only the twist of the optical transmission part 11a can be visually detected, but also the twist is automatically regulated to prevent deterioration of characteristics, improve yield, and easily maintain product quality. At the same time, the workability is further improved, and the winding work can be automated easily.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical fiber and a polarization-maintaining fiber-wound-type polarizer using the same, and more specifically, an optical transmission part formed of a so-called polarization-maintaining fiber and a jacket sheath for covering the optical transmission part are integrated. TECHNICAL FIELD The present invention relates to an optical fiber provided for the purpose and a polarization-maintaining fiber wound type polarizer using the optical fiber.

[0002]

[Prior art]

 Generally, this type of optical fiber is equipped with an optical transmission part consisting of a single mode fiber with a large birefringence index and a jacket sheath that covers the optical transmission part, and by applying non-axisymmetric stress to the optical transmission part. The desired polarization characteristics are obtained.

For example, Japanese Utility Model Laid-Open No. 59-4503 discloses an inner jacket sheath having a non-circular cross-section that covers the light transmission section, and a circular outer circumference that covers the inner jacket sheath while preserving the twist of the inner jacket sheath. A configuration including an outer jacket sheath having a cross-sectional shape has been proposed. However, it is extremely difficult in manufacturing to preserve the twist of the inner jacket sheath by the outer jacket sheath while making the jacket sheath into a two-layer structure, and it is easily affected by external force.

Therefore, when constructing a polarization-maintaining fiber-wound type polarizer using the above-mentioned optical fiber, usually, an optical transmission part made of a single mode fiber having a large birefringence is wound around a cylindrical bobbin or the like. By wrapping around the body in multiple layers and fixing only the part near the beginning and end of the winding (hereinafter referred to as the "winding end") with, for example, a silicone adhesive, It was trying to prevent the influence of external force due to loosening and twisting / pulling.

However, the conventional structure has a problem in that when the optical fiber is twisted during winding, desired polarization characteristics cannot be obtained. To solve such a problem, Japanese Utility Model Laid-Open No. 60-120411 discloses an optical fiber having a jacket sheath formed in a circular cross-sectional shape, in which the polarization plane of the optical fiber is provided on the outer peripheral surface of the jacket sheath. There is disclosed a technique in which a line mark coinciding with the main axis of the optical fiber is provided in parallel with the axis of the optical fiber.

[0006]

[Problems to be solved by the device]

 However, in the configuration described in Japanese Utility Model Laid-Open No. 60-120411, the twist of the optical fiber can only be visually detected, and therefore it is necessary to perform the operation of correcting the twist when the optical fiber is wound. Therefore, the workability during manufacturing was still poor, and it was difficult to improve the yield and automate the winding work.

In addition, the above-mentioned polarization-maintaining fiber-wound type polarizer has a defect that twisting is likely to occur not only in the winding portion of the optical fiber but also in the extra length portion of the optical fiber, so that the above-mentioned problems are further caused. It was getting serious. Therefore, an object of the present invention is to solve the above-mentioned technical problems, prevent characteristic deterioration due to twisting, improve yield and facilitate product quality maintenance, and further improve workability. It is an object of the present invention to provide an optical fiber that can be easily improved to automate the winding work, and a polarization-maintaining fiber-wound polarizer using the optical fiber.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention integrally includes an optical transmission part made of a single mode fiber having a large birefringence index and a jacket sheath for covering the optical transmission part. An optical fiber that is wound a large number of times with a predetermined tension applied to the attachment surface, wherein the jacket sheath has a copying portion that follows the winding surface while restricting the twist of the optical transmission portion. The optical fiber is characterized by having a circular cross-sectional shape.

Further, it is preferable that the jacket sheath covers a reinforcing core arranged in parallel with the optical transmission section in a state of facing in the width direction of the copying section. Furthermore, it is more preferable that the jacket sheath covers the optical transmission portions arranged in a plurality of rows in a state of facing each other in the width direction of the copying portion. On the other hand, the polarization-maintaining fiber-wound type polarizer according to the present invention comprises a wound body having a circular cross section, an optical transmission section made of a single-mode fiber having a large birefringence index, and a jacket sheath covering the optical transmission section. It is integrally provided, and is wound a number of times with a predetermined tension being applied to the outer peripheral winding surface of the wound body, and the jacket sheath is wound in the state where the twist of the optical transmission part is regulated. An optical fiber having a non-circular cross-sectional shape having a copying portion that follows the surface, and a fixing portion that integrally fixes the extra length portion of the optical fiber to the winding body, and the fixing portion includes: It is characterized in that the outer peripheral surface of the jacket sheath is arranged to form a guide surface for restricting the twist of the extra length portion of the optical fiber.

[0010]

[Action]

 According to the above configuration, when the optical fiber is wound around the winding body while applying a predetermined tension to the optical fiber at the time of manufacturing, the copying section formed in the jacket sheath of the optical fiber causes the winding surface of the winding body to move. The optical transmission part can be prevented from being twisted by being wound in a state of following the above.

Further, according to the optical fiber of the second aspect, the jacket sheath covers the reinforcing core arranged in parallel with the optical transmission section in a state of facing in the width direction of the copying section. There is an advantage that the portion can more easily follow the winding surface of the winding body. Further, according to the optical fiber of claim 3, the jacket sheath covers the plurality of optical transmission parts arranged in parallel in a state of facing each other in the width direction of the copying part. In addition to achieving the same effect as an optical fiber, it is possible to wind multiple times the number of optical transmission parts with the same number of turns.

On the other hand, according to the polarization-maintaining fiber-wound polarizer of the present invention, the optical fiber is provided with a jacket sheath having a non-circular cross-sectional shape having a profile, and the extra length of the optical fiber is provided. Since the fixing portion to be fixed forms a guide surface that regulates the twist of the extra length portion of the optical fiber by laying along the outer peripheral surface of the jacket sheath, as in the device according to claim 1, In addition to being able to prevent twisting of the transmission section, the excess length of the optical fiber is restricted from displacement in the twisting direction by the guide surface.

[0013]

【Example】

 Embodiments will be described in detail below with reference to the accompanying drawings. FIG. 1 is an enlarged view of a main part of a polarization-maintaining fiber-wound polarizer according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of an optical fiber of the polarization-maintaining fiber-wound polarizer. FIG. 3 shows the polarization-maintaining fiber wound type polarizer, (A) is a schematic perspective view of the polarization-maintaining fiber wound type polarizer, and (B) is the polarization-maintaining fiber. FIG. 4 is a schematic plan view of a wound-type polarizer, FIG. 4 is an enlarged view of a main part showing a fixed portion of the above polarization-maintaining fiber-wound polarizer, and FIG. It is a schematic perspective view which shows the manufacturing process of a shaped polarizer.

First, referring to FIGS. 1 to 3 (A) and (B), the polarization-maintaining fiber-wound type polarizer 10 has an optical fiber 1 and a bobbin 2. First, referring to FIGS. 3 (A) and 3 (B), the hobbin 2 includes a hollow cylindrical body 2a made of resin or metal and a substantially circular upper side extending substantially concentrically at the upper end of the hollow cylindrical body 2a. The flange portion 2b, a substantially circular lower flange portion 2c extending substantially concentrically at the lower end of the hollow cylindrical body 2a, an upper extending portion 12b extending in one tangential direction of the upper flange portion 2b, and a lower portion. The side flange portion 2c is integrally provided with a lower extension portion 12c extending in a tangential direction that is opposite to the one tangential direction. As will be described later in detail, the extending portions 12b and 12c are provided with fixing portions b and c for fixing the extra length portions 1a and 1b of the corresponding optical fiber 1, respectively.

In this embodiment, the radius of curvature of the winding portion 1c is set smaller than the radius of curvature of the extra length portions 1a and 1b. The extra length portions 1a and 1b have a predetermined radius of curvature, but the fixing portions b and c may be arranged so as to extend linearly in the tangential direction of the winding portion 1c. preferable. Further, in the present embodiment, the winding end portion of the optical fiber 1 is fixed to the hollow cylindrical body 2a of the bobbin 2 with the silicon adhesive 3 or the like, and the optical fiber extending from the winding end portion is fixed. The fixing portions b of the extending portions 12b and 12c, which are corresponding to each other by the adhesive 3, in a state where the extra length portions 1a and 1b of 1 are along an arc having a radius of curvature larger than the radius of curvature of the winding portion 1c, It is fixed to c (see FIG. 4).

The optical fiber 1 of the present embodiment is wound around the hollow cylindrical body 2a a number of times, so that the extra length portion 1a on the incident side on which light is incident and the extra length portion on the outgoing side on which light is emitted are provided. This is a so-called polarization-maintaining fiber that constitutes the long portion 1b and the winding portion 1c formed between the extra length portions 1a and 1b, and as shown in FIG. 1, a single mode fiber with a large birefringence index. And a jacket sheath 12 that covers the optical transmission unit 11 are integrally provided.

Referring to FIG. 2, the optical transmission unit 11 includes a core 11a formed of silica glass having a high refractive index, and a clad 11b formed of silica glass having a low refractive index and covering the outer periphery of the core 11a. Is equipped with. The optical transmission unit 11 applies non-axisymmetric stress to the core 11a and propagates two polarization components orthogonally in the optical transmission unit 11 (hereinafter, "X polarization component" and "Y polarization component", respectively). Polarization component ") gives a difference in refractive index between the polarized components, and when light having a predetermined wavelength is passed through the extra length portion 1a on the incident side, the non-axial symmetry of the optical fiber 1 causes Differences in the wavelength characteristics of the loss of the X polarization component and the Y polarization component are caused, and one polarization component (for example, X polarization component) is not transmitted and only the other polarization component (Y polarization component) is transmitted. Is transmitted and is output from the extra length portion 1b on the emission side.

As is apparent from FIGS. 1 and 2, the jacket sheath 12 is made of plastic having a predetermined rigidity and flexibility, and its cross-sectional shape is elliptical. The portion forming the inner peripheral portion of the winding portion 1c constitutes a copying portion 12A that follows the winding surface of the hollow cylindrical body 2a in a state in which the twist of the optical transmission portion 11 is restricted.

Next, referring to FIG. 4, the fixing portions b and c provided on the respective extending portions 12b and 12c of the bobbin 2 are provided with notch grooves b1 and c1 whose upper ends or lower ends are open, The extra lengths 1a and 1b of the optical fiber 1 are firmly fixed by an adhesive 3 with the outer circumference of the jacket sheath 12 fitted in the corresponding notched grooves b1 and c1. Here, the width dimensions of the cutout grooves b1 and c1 are set so that the width in the minor axis direction in the cross section of the jacket sheath 12 can be sandwiched. As a result, the notch grooves b1 and c1 form guide surfaces that regulate the twisting of the extra lengths 1a and 1b of the optical fiber 1 by laying along the copying portion 12A of the jacket sheath 12.

As shown in FIG. 5, when manufacturing the polarization-maintaining fiber-wound polarizer 10 according to this embodiment, first, the bobbin 2 is rotatably supported by a predetermined rotation driving device, and then the bobbin 2 is rotatably supported. The one end portion side of the optical fiber 1 drawn out from the optical fiber supply portion (not shown) may be fixed to one fixing portion c (b), and the bobbin 2 may be rotated in the winding direction indicated by the arrow R. As a result, the optical fiber 1 is wound around the hollow cylindrical body 2a while a predetermined tension is applied, and as a result, the copying portion 12A (see FIG. 2) formed on the jacket sheath 12 of the optical fiber 1 becomes hollow. It is wound in a state following the winding surface of the cylindrical body 2a. When the winding operation is completed, the optical fiber 1 on the optical fiber supply section side is cut, and the end side is fixed to the other fixing section b (c) to wind the desired polarization plane preserving fiber. The shaped polarizer 10 can be manufactured. In this embodiment, in the above process, the guide 13 is provided between the optical fiber supply unit and the bobbin 2. The guide 13 is provided with an insertion hole 13a along the cross-sectional shape of the jacket sheath 12 of the optical fiber 1, and the optical fiber 1 is supplied from the optical fiber supply section to the bobbin 2 side through the insertion hole 13a. The optical fiber 1 is prevented from being twisted inside.

According to the optical fiber 1 having the above-described configuration, the copying section 12A formed on the jacket sheath 12 of the optical fiber 1 is wound in a state of following the winding surface of the hollow cylindrical section 2a, and the optical transmission section is formed. Since it is possible to prevent the twist of the optical fiber 11a, it is possible not only to visually detect the twist of the optical transmission part 11a, but also to prevent the characteristic from being deteriorated by automatically controlling the above-mentioned twist, and the yield is improved. As a result, the product quality can be easily maintained, the workability is further improved, and the winding work can be automated easily, which is a remarkable effect.

In addition, according to the polarization-maintaining fiber-wound polarizer 10 of this embodiment, the extra lengths 1a and 1c of the optical fiber 1 are restricted from being displaced in the twisting direction by the guide surface. In addition to being able to solve problems caused by twisting of the wound portion of the optical fiber 1, it is also possible to prevent deterioration of characteristics due to twisting of the extra lengths 1a and 1c of the optical fiber 1, which improves yield and facilitates maintaining product quality. The workability is further improved, and the winding work can be automated easily, which is a remarkable effect.

In the present embodiment, the extra lengths 1 a and 1 b of the optical fiber 1 extending from the winding end portion have a radius of curvature larger than that of the winding portion 1 c wound around the bobbin 2. Since they are fixed along the circular arc of, the influence of external force on the fixed portions a and b of the extra length portions 1a and 1b can be reduced as much as possible from being transmitted to the winding portion 1c. it can. Therefore, according to this embodiment, it is possible to reliably prevent the influence of external force from being transmitted to the winding portion 1c of the optical fiber 1, even if the fixed state of the winding end portion is incomplete. it can.

Particularly, in this embodiment, since the extra length portions 1a and 1b are fixed to the corresponding flange portions 2b and 2c of the bobbin 2 through the fixing portions b and c, respectively, the polarization plane preserving fiber winding is performed. There is an advantage that the mounting work for attaching the shaped polarizer 10 to other devices or members becomes easy. Further, in the present embodiment, since the fixing portions b and c are provided on the extending portions 12b and 12c of the corresponding collar portions 2b and 2c, the extra length portions are stretched more linearly. Can be installed to prevent twisting.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, as shown in FIG. 6, by adopting a jacket sheath 102 having a recess 12b extending along the longitudinal direction of the optical transmission part 11, the copying parts 12A may be formed on both widthwise ends of the recess 12b. .

Further, as shown in FIG. 7, by adopting the jacket sheath 112 having the protrusion 12c extending along the longitudinal direction of the optical fiber 1, even if the copying portion 12A is formed on one side surface side of the protrusion 12c. Good. Further, as shown in FIG. 8, a jacket sheath 122 having an oval cross section may be adopted. In this case, one straight portion of the jacket sheath 122 constitutes a copying portion 12A which follows the winding surface of the hollow cylindrical portion 2a in a state where the twist of the light transmitting portion 11 is restricted. Further, the jacket sheath 122 covers the reinforcing core 14 arranged in parallel with the optical transmission section 11 while facing the width direction of the copying section 12A. This has the advantage that the copying portion 12A can more easily follow the winding surface of the hollow cylindrical portion 2a, and therefore workability and mechanization during manufacturing are further facilitated.

Further, as shown in FIG. 9, a plurality of optical transmission parts 11 in which jacket sheaths 122 having the same oval cross section as in FIG. 8 are arranged in parallel in a state of facing in the width direction of the copying part 12A, 11 may be covered. According to this configuration, the same working effect as that of the embodiment of FIG. 8 is obtained, and the winding work is facilitated in that the optical transmission parts 11, 11 can be wound a plurality of times with the same number of windings. .

Although not specifically shown, when the present invention is applied to, for example, a navigation system, it is possible to fix the extra lengths 1a and 1b directly to the housing of the optical fiber gyro. In addition, various modifications can be made within a range that does not change the gist of the present invention, such as omitting the adhesive 3 as a means for fixing the winding end portion 1c and the extra length portions 1a and 1b. Needless to say.

[0029]

[Effect of device]

 As described above, according to the present invention, the copying part formed in the jacket sheath of the optical fiber is wound in a state of following the winding surface of the winding body to prevent the optical transmission part from being twisted. Therefore, it is possible not only to visually detect the twist of the optical transmission part, but also to automatically control the twist to prevent deterioration of characteristics, improve yield, and easily maintain product quality. In addition, the workability is further improved, and the winding operation can be easily automated, which is a remarkable effect.

Further, according to the optical fiber of the second aspect, the jacket sheath covers the reinforcing core arranged in parallel with the optical transmission section in a state of being opposed to each other in the width direction of the copying section. Since there is an advantage that the portion can more easily follow the winding surface of the winding body, workability and mechanization at the time of manufacturing are further facilitated. Further, according to the optical fiber of claim 3, the jacket sheath covers the plurality of optical transmission parts arranged in parallel in a state of facing each other in the width direction of the copying part. In addition to the effect similar to that of the optical fiber, the winding work is facilitated in that the optical transmission section can be wound multiple times with the same number of windings.

On the other hand, according to the polarization-maintaining fiber-wound polarizer according to claim 4 of the present invention, the extra length of the optical fiber is restricted from being displaced in the twisting direction by the guide surface, and as a result, the optical fiber is wound. In addition to being able to solve problems caused by twisting of the turning part, it is also possible to prevent deterioration of characteristics due to twisting of the excess length of the optical fiber, improving yield and making it easier to maintain product quality, and further improving workability. The remarkable effect is that the winding work can be automated easily.

Therefore, according to the present invention, it is possible to prevent the characteristic deterioration due to the twist of the optical transmission part, improve the yield and easily maintain the quality of the product, and further improve the workability to further improve the winding performance. It is also possible to easily automate the turning work.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part of a polarization-maintaining fiber-wound polarizer according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an optical fiber of the polarization-maintaining fiber-wound type polarizer.

3A and 3B show the polarization-maintaining fiber-wound polarizer, FIG. 3A is a schematic perspective view of the polarization-maintaining fiber-wound polarizer, and FIG. It is a schematic plan view of a shaped polarizer.

FIG. 4 is an enlarged view of a main part showing a fixed part of the polarization-maintaining fiber-wound polarizer.

FIG. 5 is a schematic perspective view showing a manufacturing process of the polarization-maintaining fiber-wound polarizer.

FIG. 6 is an enlarged cross-sectional view of an optical fiber according to another embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view of an optical fiber according to still another embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view of an optical fiber according to still another embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of an optical fiber according to still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical fiber 2 Bobbin 2a Hollow cylindrical body (winding body) 11 Optical transmission part 12 Jacket sheath 12A Copying part 102 Jacket sheath 112 Jacket sheath

Claims (4)

[Scope of utility model registration request] 1. A light transmission section made of a single mode fiber having a large birefringence, and a jacket sheath covering the light transmission section are integrally provided, and a predetermined tension is applied to the outer peripheral winding surface of a winding body having a circular cross section. An optical fiber that is wound many times in a given state, wherein the jacket sheath is formed in a non-circular cross-sectional shape having a copying portion that follows the winding surface in a state in which the twist of the light transmission portion is regulated. An optical fiber characterized in that 2. The optical fiber according to claim 1, wherein the jacket sheath covers a reinforcing core that is arranged in parallel with the optical transmission section in a state of facing in the width direction of the copying section. 3. The optical fiber according to claim 1, wherein the jacket sheath covers a plurality of optical transmission parts arranged side by side in the width direction of the copying part. 4. A winding body having a circular cross section, an optical transmission section made of a single mode fiber having a large birefringence index, and a jacket sheath covering the optical transmission section, which are integrally provided, and the outer peripheral winding of the winding body. The jacket sheath is wound a large number of times with a predetermined tension being applied, and the jacket sheath is formed in a non-circular cross-sectional shape having a copying portion that follows the winding surface in a state in which the twist of the light transmission portion is regulated. Optical fiber and a fixing portion that integrally fixes the extra length portion of the optical fiber to the wound body, and the optical fiber is provided by aligning the outer peripheral surface of the jacket sheath with the fixing portion. A polarization-maintaining fiber-wound polarizer, characterized in that it forms a guide surface for restricting the twist of the extra length portion.