WO1994019714A1 - Polarized wave holding optical fiber, production method therefor, connection method therefor, optical amplifier, laser oscillator and polarized wave holding optical fiber coupler - Google Patents
Polarized wave holding optical fiber, production method therefor, connection method therefor, optical amplifier, laser oscillator and polarized wave holding optical fiber coupler Download PDFInfo
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- WO1994019714A1 WO1994019714A1 PCT/JP1994/000300 JP9400300W WO9419714A1 WO 1994019714 A1 WO1994019714 A1 WO 1994019714A1 JP 9400300 W JP9400300 W JP 9400300W WO 9419714 A1 WO9419714 A1 WO 9419714A1
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- optical fiber
- polarization
- maintaining optical
- core
- refractive index
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/024—Optical fibres with cladding with or without a coating with polarisation maintaining properties
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
- C03B37/01211—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
- C03B37/01217—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube for making preforms of polarisation-maintaining optical fibres
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
- C03B37/01211—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube
- C03B37/01222—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments by inserting one or more rods or tubes into a tube for making preforms of multiple core optical fibres
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02042—Multicore optical fibres
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
- G02B6/2821—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals
- G02B6/2843—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using lateral coupling between contiguous fibres to split or combine optical signals the couplers having polarisation maintaining or holding properties
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
- C03B2201/31—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with germanium
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/30—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi
- C03B2201/34—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with rare earth metals, i.e. with Sc, Y or lanthanides, e.g. for laser-amplifiers
- C03B2201/36—Doped silica-based glasses doped with metals, e.g. Ga, Sn, Sb, Pb or Bi doped with rare earth metals, i.e. with Sc, Y or lanthanides, e.g. for laser-amplifiers doped with rare earth metals and aluminium, e.g. Er-Al co-doped
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/02—External structure or shape details
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/10—Internal structure or shape details
- C03B2203/12—Non-circular or non-elliptical cross-section, e.g. planar core
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/10—Internal structure or shape details
- C03B2203/22—Radial profile of refractive index, composition or softening point
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/30—Polarisation maintaining [PM], i.e. birefringent products, e.g. with elliptical core, by use of stress rods, "PANDA" type fibres
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/30—Polarisation maintaining [PM], i.e. birefringent products, e.g. with elliptical core, by use of stress rods, "PANDA" type fibres
- C03B2203/31—Polarisation maintaining [PM], i.e. birefringent products, e.g. with elliptical core, by use of stress rods, "PANDA" type fibres by use of stress-imparting rods, e.g. by insertion
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2203/00—Fibre product details, e.g. structure, shape
- C03B2203/34—Plural core other than bundles, e.g. double core
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/255—Splicing of light guides, e.g. by fusion or bonding
- G02B6/2551—Splicing of light guides, e.g. by fusion or bonding using thermal methods, e.g. fusion welding by arc discharge, laser beam, plasma torch
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/255—Splicing of light guides, e.g. by fusion or bonding
- G02B6/2552—Splicing of light guides, e.g. by fusion or bonding reshaping or reforming of light guides for coupling using thermal heating, e.g. tapering, forming of a lens on light guide ends
Definitions
- Polarization-maintaining optical fiber its manufacturing method and connection method, optical amplifier, laser oscillator, and polarization-maintaining optical fiber
- the present invention relates to a polarization maintaining optical fiber used for various optical fiber sensors and the like, a method of manufacturing and connecting the same, an optical amplifier, a laser oscillator, and a polarization maintaining optical fiber power bra.
- Fig. 22 (a) to (d) show conventional typical polarization-maintaining optical fibers.
- (A) is called an elliptical core type, in which the core is deformed from a circular shape to non-axisymmetric. The degeneration between two polarization modes is solved. The propagation constant between the modes is made different to maintain the polarization.
- Fig. 22 (b) shows the elliptical cladding type, (c) shows the bowtie type, and (d) shows the PAN DA type, which is not symmetric (non-axisymmetric) with respect to the central axis of the optical fiber.
- reference numeral 1 denotes a core
- 2 denotes a clad
- 3 denotes a jacket
- 4 denotes a stress applying portion
- the PANDA type polarization maintaining optical fiber which is currently used most frequently, is explained.
- a core-type single-mode type load glass preform is manufactured by the VAD method or the like.
- a glass rod to be the stress applying part is created by VAD method. Since this Garasuro head is to increase the thermal expansion coefficient, but 2 0 by weight per cent boron oxide (B 2O 3) is Dove, in such a large amount of beta 2 0 3 is de blanking quartz glass However, due to its thermal shrinkage, it is extremely fragile and requires careful attention to its processing. .
- the rod is inserted into the tube, then the whole is heated to be co-plused and integrated, but this method is applied to the glass lock as the above-mentioned stress applying part. If applied to a glass rod, the glass rod will break during cooling.
- an object of the present invention is to provide a polarization-maintaining optical fiber that can be easily manufactured and can be supplied at low cost, and a method for manufacturing the same.
- a polarization-maintaining optical fiber power bra (hereinafter abbreviated as a power bra) that branches, merges, demultiplexes, and multiplexes light among a plurality of optical fibers while maintaining the polarization of propagating light.
- polarization-maintaining optical fibers such as elliptical core type, elliptical clad type, and PANDA type.
- two or more polarization-maintaining optical filters 5, 5 are in contact with each other so as to be in contact with each other. It is manufactured by a method of heating, fusing, and lightly stretching this portion to form a joint 6.
- this manufacturing method is not limited to the polarization maintaining optical fiber, but is a general single mode. Is widely applied to optical fiber, etc., and is technically established as a known technology.
- Such a power bra has the following problems. First, it is difficult to manufacture the polarization-maintaining optical fiber itself, which increases the manufacturing cost. Second, the degree of freedom of the power bra coupling style is restricted. Third, in order to obtain good performance such as excess loss, the structure, design, and manufacturing method of the polarization-maintaining optical fiber itself may need to be changed.
- an object of the present invention is to obtain a power plug that is easy to manufacture, has a high degree of freedom in a coupling mode, and has good characteristics.
- Another object of the present invention is to provide a method for fusion splicing the polarization maintaining optical fiber obtained by the above-mentioned present invention with low loss.
- single-mode optical fibers in which rare earth elements such as neodymium (Nd), erbium (Er), and samarium (Sm) are added to the core have been known from the past, and have already been used in optical fiber amplifiers, It is used for laser oscillators and the like.
- the core of a conventional polarization-maintaining optical fiber may be doped with a rare-earth element.
- a polarization-maintaining optical fiber is used. It is difficult to fabricate the fiber itself, and a process of adding a rare earth element to the core is added, which requires a great deal of labor and increases the manufacturing cost.
- another object of the present invention is to provide a rare earth-doped polarization maintaining optical fiber which can be easily manufactured and supplied at low cost, a method for manufacturing the same, and an optical amplifier and a laser oscillator.
- a plurality of core portions of a high refractive index region are provided in parallel along one diameter direction of the optical fiber, and these core portions integrally propagate one basic mode. It is something to do.
- one area is formed By dividing the formed core into a plurality of regions, that is, the core portion at a narrow interval, an extremely high flatness or ellipticity can be effectively generated, and good polarization maintaining characteristics can be obtained. it can. In addition, manufacturing becomes simple.
- the method for manufacturing a polarization-maintaining optical fiber according to the present invention is a method for manufacturing the polarization-maintaining optical fiber, wherein the core glass port having a plurality of core bodies is provided with a Then, it is inserted into the hole of the glass rod for cladding that has one hole to be heated and integrated, and then melt-spun. Therefore, the above-mentioned polarization maintaining optical fiber can be easily and efficiently manufactured at low cost.
- the polarization-maintaining optical fiber force bra of the present invention is obtained by heating, fusing and stretching two or more polarization-maintaining optical fibers.
- the vicinity of the connection point is heated before or after the connection. For this reason, it is possible to eliminate the mismatch of the mode field shape in the connection between the polarization maintaining optical fibers having the elliptical electric field distribution shape of the present invention, and it is possible to reduce the connection loss.
- the rare earth-doped polarization maintaining optical fiber of the present invention is provided with a plurality of high refractive index region cores arranged side by side in one diameter direction of the optical fiber, and these cores integrally propagate one fundamental mode. It has a polarization maintaining function, and has a rare-earth element added to one or both of the core portion and the cladding portion of the low refractive index region sandwiched between the core portions. For this reason, the polarization maintaining characteristics are good, the optical amplification function is excellent, and the polarization axis alignment at the time of fusion splicing becomes easy.
- optical amplifier and the laser oscillator of the present invention use the rare earth-doped polarization maintaining optical filter, they output output light having good polarization characteristics.
- FIG. 1A is a sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- FIG. 1B is a sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- 1) is a cross-sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- FIG. 1 (d) is a cross-sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- FIG. 1E is a cross-sectional view illustrating an example of the polarization maintaining optical fiber of the present invention.
- FIG. 1 (f) is a sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- FIG. 2 (a) is a diagram showing a refractive index distribution in the X-axis direction of the polarization maintaining optical fiber of the present invention.
- FIG. 2 (b) is a diagram showing a refractive index distribution in the y-axis direction of the polarization maintaining optical fiber of the present invention.
- FIG. 2 (C) is a diagram showing the refractive index distribution in the y′-axis direction of the polarization maintaining optical fiber of the present invention.
- FIG. 2D is a diagram showing a mode distribution in the X-axis direction of the polarization maintaining optical fiber of the present invention.
- FIG. 2 (e) is a diagram showing a mode distribution in the y-axis direction of the polarization maintaining optical fiber of the present invention.
- FIG. 3 (a) is a cross-sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- FIG. 3B is a cross-sectional view showing an example of the polarization maintaining optical fiber of the present invention.
- FIG. 3C is a cross-sectional view illustrating an example of the polarization maintaining optical fiber of the present invention.
- FIG. 3D is a cross-sectional view illustrating an example of the polarization maintaining optical fiber of the present invention.
- FIG. 4 (a) is a diagram showing a refractive index distribution of another example of the polarization maintaining optical fiber of the present invention.
- FIG. 4B is a diagram showing a refractive index distribution of another example of the polarization maintaining optical fiber of the present invention.
- FIG. 5 is a diagram showing an intermediate base material in Example 1 of the present invention.
- FIG. 6 is a cross-sectional view of the polarization-maintaining optical fiber obtained in Example 1 of the present invention.
- FIG. 7 is a schematic perspective view showing an example of the production method of the present invention.
- FIG. 8 is a schematic sectional view of a base material in one example of the production method of the present invention.
- FIG. 9 is a schematic plan view showing another example of the production method of the present invention.
- FIG. 10 (a) is a cross-sectional view showing an example of the polarization maintaining optical fiber power bra of the present invention.
- FIG. 10 (b) is a cross-sectional view showing an example of the polarization maintaining optical fiber hood of the present invention.
- FIG. 10 (c) is a cross-sectional view showing an example of the polarization maintaining optical fiber hood of the present invention.
- FIG. 11A is a cross-sectional view showing another example of the polarization-maintaining optical fiber power bra of the present invention.
- FIG. 11 (b) is a cross-sectional view showing another example of the polarization-maintaining optical fiber according to the present invention.
- Fig. 12 is a graph showing the relationship between the coupling portion and the wavelength in an example of the force bra of the present invention.
- FIG. 13 shows the propagation model of the polarization maintaining optical fiber in the polarization maintaining optical fiber connection method of the present invention.
- FIG. 4 is a diagram showing an electric field intensity distribution of a gate.
- Fig. 14 (a) is a diagram schematically showing the discontinuity of the electric field distribution in the mode of the two polarization-maintaining optical fibers.
- FIG. 14 (b) is a diagram schematically showing the discontinuity of the electric field distribution in the mode of the two polarization-maintaining optical fibers.
- FIG. 14 (c) is a diagram schematically showing the discontinuity of the electric field distribution in the mode of the two polarization maintaining optical fibers.
- FIG. 14 (d) is a diagram schematically showing the discontinuity of the electric field distribution in the mode of the two polarization-maintaining optical fibers.
- FIG. 15 is a graph showing a change in the cross-sectional shape of the propagation mode due to heating.
- FIG 1 6 (a) is a c Figure 1 6 is a sectional view showing the rare-earth-doped polarization-maintaining optical fiber of the present invention
- (b) is a sectional view showing the rare-earth-doped polarization-maintaining optical fiber of the present invention
- Figure 1 6 is a sectional view showing the rare-earth-doped polarization-maintaining optical Fuaipa (d) of the present invention is a cross-sectional view showing the rare-earth-doped polarization-maintaining optical fiber of the present invention.
- FIG. 16 (e) is a cross-sectional view showing a rare earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 16 (f) is a cross-sectional view showing the rare earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 17 (a) is a diagram showing a refractive index distribution in the X-axis direction of the rare earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 17 (b) is a diagram showing the refractive index distribution in the y-axis direction of the rare earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 17 (c) is a diagram showing a refractive index distribution in the y′-axis direction of the rare earth-doped polarization maintaining optical fiber of the present invention.
- Fig. 17. (d) is a diagram showing a mode distribution in the X-axis direction of the rare earth-doped polarization maintaining optical fiber of the present invention. .
- Fig. 17 (e) shows the mode distribution in the y-axis direction of the rare earth-doped polarization-maintaining optical fiber of the present invention.
- FIG. 18 (a) is an if-plane view showing a rare-earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 18 (b) is a cross-sectional view showing a rare-earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 18 (c) is a cross-sectional view showing a rare earth-doped polarization maintaining optical fiber of the present invention, and
- FIG. 18 (d) is a cross-sectional view showing a rare earth doped polarization maintaining optical fiber of the present invention.
- FIG. 19 (a) is a cross-sectional view showing another example of the rare earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 19 (b) is a cross-sectional view showing another example of the rare earth-doped polarization maintaining optical fiber of the present invention.
- FIG. 20 is a configuration diagram showing an example of the optical amplifier of the present invention.
- FIG. 21 is a configuration diagram showing an example of the laser oscillator of the present invention.
- FIG. 22 (a) is a cross-sectional view showing an example of a conventional polarization maintaining optical fiber.
- FIG. 22 (b) is a cross-sectional view showing an example of a conventional polarization maintaining optical fiber.
- FIG. 22 (c) is a cross-sectional view showing an example of a conventional polarization maintaining optical fiber.
- FIG. 22 (d) is a cross-sectional view showing an example of a conventional polarization maintaining optical fiber.
- FIG. 23 is a perspective view showing a conventional force bra.
- the polarization-maintaining optical fiber 10 shown in FIG. 1 (a) has a clad 11 made of low-refractive-index glass having a circular cross-section and a cross-section made of high-refractive-index glass having a circular cross-section. It is composed of core sections 12a and 12b.
- the core portions 12a and 12b pass through the central axis 0 of the optical fin 10 and are arranged opposite to each other in plane symmetry with respect to one surface along the axial direction. That is, two core portions 12 a and 12 b are arranged side by side in one diameter direction (X-axis direction) of the optical fiber 10.
- the cores 12a and 12b have the same diameter and the same diameter.
- the diameter is about 2 to 4 depending on the wavelength used and the relative refractive index difference between the cores 12a and 12b. It is about 10 m.
- the distance between one core portion 12a and the other core portion 12b is determined by the dimension 1 between the centers of the core portions 12a and 12b shown in FIG. The selection is made in the range of about 0.5 to 3 times the radius of 2a and 12b.
- the relative refractive index difference between the cores 12a and 12b and the clat '11 is 0.15 to 3.0%.
- Fig. 1 (b) differs from the example shown in Fig. 1 in that both cores 12a and 12b have a rectangular cross-sectional shape.
- the square may be a square or a rectangle.
- the long sides of the core portions 12a and 12b are about 2 to 10 m, the short sides are 2 to 1 O xim, and the interval 1 is about 1 to 3 times the short side.
- Fig. 1 (c) The one shown in Fig. 1 (c) consists of four rectangular cores 12a, 12b, 12c, and 12d, and these four cores as a whole have essentially one fundamental mode. Is propagated.
- the cross-sectional shape of the cladding 11 is elliptical, and its major axis direction and the cores 12a, 12b ( 12 c, 12 d).
- Figs. 2 (a) to 2 (e) schematically show the refractive index distribution of the polarization-maintaining optical fiber shown in Fig. 1 (b) and the mode distribution of the fundamental mode propagating through the cores 12a and 12b.
- A) is the refractive index distribution in the X-axis direction
- (b) is the refractive index distribution in the y-axis direction
- (c) is the refractive index distribution in the y'-axis direction
- (d) is the X-axis direction.
- E) shows the mode distribution in the y-axis direction. From this figure, the mode distribution in the X-axis direction extends to the area between the cores 12a and 12b and extends to the area of 1.1. It is quite different from the refractive index distribution.
- the mode distribution in the y-axis direction is almost the same as the mode distribution of a normal single mode fiber. '
- the mode distributions in the X-axis direction and the y-axis direction are different from each other, indicating non-axial symmetry.
- a waveguide structure birefringence B g is generated, and polarization retention is generated.
- the polarization maintaining fiber of the present invention if a glass having a larger coefficient of thermal expansion than the gas forming the cladding 11 is used for the glass forming the cores 12 a.
- the non-axisymmetric internal stress generated in the spinning ⁇ ⁇ is generated in the cores 12 a and 12 b themselves, and the internal stress expresses the stress-induced birefringence B s, which also indicates the polarization maintaining property. Appears. Since the stress-induced birefringence Bs is added to the waveguide structure birefringence Bg, the birefringence B as a whole becomes large.
- 3 (a) to 3 (d) show other examples of the polarization maintaining optical fiber of the present invention.
- the one shown in Fig. 3 (a) has an odd number (three) of cores 12a, 12b, and 12c, and the core 12a at the center is the center of the fiber. It is arranged so as to coincide with the central axis 0.
- the distance between the cores 12a, 12b, and 12c and the relative refractive index difference from the clad 11 are the same as in the previous example.
- the central core portion 12a does not necessarily have to coincide with the central axis 0 of the fiber.
- the shape of each core portion may be rectangular as in the previous example, or the cross-sectional shape of the clad 11 may be elliptical. Further, as shown in FIG. 3 (b), it may have five core portions 12a, 12b, 12c, 12d, and 12e.
- the cross-sectional shape of the cores 12a and 12b is a slightly curved cross-sectional shape.
- a non-symmetrical shape such as a circle or a square can be employed.
- each of the core portions 12 a and 12 b may have a different cross-sectional shape.
- the refractive index distribution in one core part is uniform as shown in Fig. 2 (a). There is no necessity. For example, a distribution having a mountain shape as shown in FIG. 4 (a) may be used. .. The relative refractive index difference between cores is slightly different as shown in Fig. 4 (b).
- Ge-added quartz and glass rod (glass rod for core, diameter 3 O mm, length 150 mm) were prepared by VAD method.
- the amount of addition of this glass rod ⁇ Ge 02 was about 9% by weight, and the relative refractive index difference from quartz glass was about 0.6%.
- the glass rod was heated and stretched in a heating furnace of about 100 * C to obtain a glass rod serving as a core having a diameter of about 5 mm.
- a pure quartz glass port which is a cladding having an outer diameter of 40 mm and a length of 200 mm was separately prepared. Two insertion holes having a diameter of 5.3 mm were pierced at an interval of 2.5 mm symmetrically with respect to the central axis. Thereafter, the above-mentioned Ge 02 -added quartz glass rods were inserted into the inserts 6, respectively, and heated and cobrased to obtain an intermediate base material having the dimensions shown in FIG.
- This intermediate base material is heated and stretched, and a quartz glass serving as a clad is formed on the outer peripheral surface of the intermediate base material by a well-known external method to form a base material, which is melt-spun, as shown in FIG. An optical fiber with a structure was created.
- the obtained optical fiber has sufficient characteristics as a polarization-maintaining optical fiber, and it can be seen that its manufacture can be performed easily as described above.
- a fluorine-added quartz glass rod (diameter of 5 O mm) was prepared as a clad.
- the relative refractive index difference from quartz glass was 10.3%.
- the core glass holes serving as the cores were inserted into these insertion holes, and heated and co-brushed to obtain an intermediate base material.
- the intermediate base material is heated and stretched, and a clad having a sufficient thickness is formed on the outer periphery thereof by a rod-in-tube method to obtain a base material, which is melt-spun.
- a clad was formed as a base material, which was melt-spun to obtain an optical fiber having a structure as shown in Fig. 3 (a).
- the diameter of the core of each optical fiber is about 1.5 m, the center separation between the cores is about 2. l yum, the cladding diameter (fiber diameter) is 80 ⁇ m, and the core diameter is 80 ⁇ m.
- the relative refractive index difference between the and the cladding was about 2.3%.
- optical characteristics of the obtained optical filter are as shown in Table 2, and it can be seen that the optical filter has good polarization maintaining characteristics.
- Table 2 The optical characteristics of the obtained optical filter is as shown in Table 2, and it can be seen that the optical filter has good polarization maintaining characteristics.
- FIG. 7 shows an example of this manufacturing method.
- a columnar glass port 21 serving as a clad is prepared.
- One concentric insertion hole 22 is formed in the center of the glass rod 21.
- the glass rod 21 is made of pure quartz, fluorine-doped quartz, or the like. Perforated ones are used.
- the core glass rod 23 has a two-layer structure, the central part of which is composed of a core body part 24 having a high refractive index as a core part, and the outer peripheral part is an outer peripheral part having a low refractive index. It consists of two and five.
- the outer peripheral portion 25 is made of pure quartz glass, fluorine-doped quartz glass, or the like, and has the same refractive index as the refractive index of the above-mentioned glass rod 21 for a cladding.
- the core main body 24 is made of germanium-doped quartz glass, pure quartz glass, or the like, and has an outer peripheral portion 25 with a relative refractive index difference of about +0.15 to 3.0%. Part 2 It has a higher refractive index than 5.
- the outer diameter ratio of the core body portion 24 to the outer peripheral portion 25 of the core glass rod '23 is such that the outer diameter of the outer peripheral portion 25 is at least 1. 5 times or more, preferably 3.times or more.
- the glass rod 23 for the core can be manufactured in the same manner as in the manufacture of a single-mode optical fiber burr ohm by the well-known VAD method or the like.
- the number of the glass rods 23 for the core is equal to the number of the cores.
- a plurality of (two) core glass rods 23 are arranged in one direction and are inserted into the insertion holes 22 of the glass rods 21 for the core. Insert it and fix it to the glass rod 21 for the clad by appropriate means. At this time, a slight gap is generated in the insert 62, but this does not cause any problem.
- the whole is heated to integrate (cobras) the plurality of glass rods 22 for core and the glass rod 21 for cladding into a base material, and then melt from the end. Spinning gives the desired polarization-maintaining optical fiber. Further, if necessary, a glass serving as a clad may be further formed on the outer peripheral surface of the base material by an external method or the like, and then melt-spun.
- FIG. 8 shows a cross section of the base material after the above-mentioned integration, and the outer peripheral portion 25 of the core glass rod 23 has the same refractive index as that of the glass rod 21. Therefore, the core body portion 24 of the core glass rod 23 cannot be identified, and the cross-sectional shape of the core body portion 24 is circular to elliptical due to the melting movement of the glass generated to fill the above-mentioned void. It is deformed.
- this new type of polarization-maintaining optical fiber has such characteristics that the power distribution in the propagation mode is hardly deformed even if the refractive index distribution of the cores is slightly deformed from the ideal shape.
- the core is elliptical as shown in Fig. 8, it shows optical characteristics that are not different from those of a circular one.
- FIG. 9 shows another example of the manufacturing method of the present invention, in which a plurality (two) of core glass rods 23 and a plurality of (five) dummy glass rods 26 are used.
- the glass material for dummies 26 is also made of glass material for cladding 21 It is made to be the same as the glass material forming the same, so that the refractive index is the same.
- the ratio of the voids in the insertion hole 22 is smaller than in the previous example, so that the deformation of the core body 24 of the core glass rod 23 is reduced, and the cross-sectional shape is circular. Is obtained.
- a plurality of core glass rods serving as a core portion are arranged at predetermined intervals and fixed at both ends, and this is used as a starting base material by an external method.
- a glass sheet that becomes a more clad is deposited, transparent vitrified to prepare a base material, and then the base material is melt-spun.
- a polarization maintaining optical fiber having good polarization maintaining characteristics and a simple structure can be manufactured very easily. Also, there is no need to use a large amount of dopant as in the conventional NDA type, and the cost of raw materials can be reduced.
- a glass rod for a core having a plurality of core bodies and a glass rod for a clad having one hole serving as a clad are provided. Since they are simultaneously inserted into the holes of the cable, heated and integrated, and then melt-spun, this new type of polarization-maintaining optical fiber can be easily, efficiently, and inexpensively manufactured.
- a glass preform for core was prepared by the VAD method, and this was then drawn by heating. More, two core-glass rods were produced.
- the outer diameter is 2 mm
- the length is 20.0 mm
- the outer diameter of the core body is 1 mm
- the core body is Ge02-doped quartz glass
- the outer periphery is stone and British glass
- the relative refractive index difference is about 1 6%.
- a commercially available high-purity quartz glass pive (inner diameter 5 mm, outer diameter 50 mm ⁇ ) is prepared as a glass for the glass.
- Two ports were inserted and arranged side by side, and were heated and integrated at 1200 ° C. to obtain a base material.
- the preform was melt spun from one end to obtain a polarization maintaining optical fiber.
- Example 3 Two core glass rods were produced in the same manner as in Example 3. However, the outer diameter was 2.5 mm, the length was 200 mm, and the outer diameter of the core body was 1.25 mm.
- dummy glass rods were manufactured by the VAD method.
- the whole was made of quartz glass and had an outer diameter of 2.5 mm and a length of 200 mm.
- the core glass rod and the dummy glass rod are arranged and bundled as shown in Fig. 7, and the insertion holes of the above-mentioned pipes are inserted, arranged, heated and integrated, and then melt-spun to maintain polarization.
- An optical fiber was used.
- the obtained polarization maintaining optical fiber had a core shape of about 2.0 ⁇ m and a short diameter of about 1.9 m, and was almost circular in shape.
- the optical characteristics were almost the same as those in Example 3, and it was recognized that the cut-off wavelength was slightly longer.
- the force bra of the present invention is made using the above-mentioned polarization maintaining optical fiber. 2.
- Figures 10 (a)-(c) show two examples of the coupling part of the obtained force bra using two polarization maintaining optical fibers of the present invention. This shows three types with different degrees of bonding between core parts 52 k and 52 b with different degrees of fusion and different degrees of fusion. The degree of this fusion is appropriately determined in consideration of the wavelength characteristics of the coupling degree of the force bra and the like.
- Figs. 11 (a) and (b) show the coupling mode of another example of the force bra according to the present invention, in which the degree of fusion is changed while maintaining the polarization planes orthogonal to each other. .
- the polarization maintaining optical fibers used may have different refractive indices.
- the wavelength of the coupling degree as shown in FIG. It is possible to obtain a power bra having a flat characteristic and a small wavelength dependence.
- Such a power bra has low loss because it does not have a complicated refractive index distribution in the cladding of the polarization maintaining optical fiber used. Further, as shown in FIGS. 10 and 11, the cross-sectional shape of the coupling portion can be freely selected, so that the wavelength characteristic of the force bra can have a large degree of freedom.
- the polarization maintaining optical fiber power bra of the present invention is made using the polarization maintaining optical fiber, it has low loss and high freedom in the coupling mode, coupling degree, and wavelength characteristics. A variety of varieties can be manufactured. In addition, since the polarization maintaining optical fiber itself can be easily manufactured, it is possible to obtain an effect that it can be supplied at low cost.
- the distance between the cores was about 4, the degree of coupling was 10%, and the excess loss was 0.1 ldB (used wavelength: 1.27 to 1.34 m). .
- the polarization-maintaining optical fiber of the present invention has features that its structure is particularly simple and extremely easy to manufacture as compared with conventional polarization-maintaining optical fibers such as PANDA type. You can do it.
- the mode distribution of the propagation mode of this polarization-maintaining optical fiber is elliptical when viewed in a cross section orthogonal to the light propagation direction as shown in Fig. 13, and its ellipticity is not necessarily It does not take a specific value and has a high degree of freedom.
- the connection point since the mode distribution of the polarization maintaining optical fiber itself is elliptical as described above and its ellipticity is not constant, the connection point , The mode distribution may be discontinuous.
- Figure 14 (a)-(d) schematically show the discontinuity of the electric field distribution in the mode of the two fibers at such a connection point, where (a) is the polarization plane. Are identical and have discontinuities due to different modes of ellipticity, (b) is for polarization planes orthogonal to each other, and (c) is for polarization. The wavefronts cross each other at 45 degrees to the reference plane, and (d) the polarization plane is shifted in parallel.
- connection loss Such discontinuity of the mode distribution at the connection point naturally appears as connection loss.
- connections are made with a polarization plane inclined by 45 degrees. Such a connection further increases the connection loss.
- a fiber whose germanium (Ge02) is added to the core to increase the refractive index is selected. This is because the germania quickly diffuses from the glass in the core to the glass in the clad by heating, and the shape of the refractive index distribution in the core, that is, the mode distribution, can be easily changed from elliptical to circular. is there.
- the heating area for heating is about 5 to 1 Omm on both sides of the connection point.
- the heating temperature is in the range of about 1500 to 1700 ° C, and the heating time is about 5 to 120 seconds.
- a heating source an arc discharge, an oxyhydrogen flame, or the like is used, and is not particularly limited.
- connection ends may be heated in accordance with the above conditions, and in the case of heating after fusion splicing, the heating may be performed under the same conditions with the connection point as the center.
- the germania in the core of the heated part diffuses into the cladding, and as a result, the cross-sectional shape of the mode distribution changes from elliptical to almost circular, The discontinuity in the mode distribution between the two fibers at the point is resolved, and the connection loss is reduced.
- connection method of the polarization maintaining optical fiber of the present invention it is possible to eliminate the mismatch of the mode field shape in the connection between the polarization maintaining optical fibers having the elliptical electric field distribution shape, and to reduce the connection loss. Can be reduced.
- a polarization maintaining optical fiber having an outer diameter of 125 im having two cores was prepared.
- the core is made of germania-added quartz gas
- the cladding is made of pure quartz glass
- the outer diameter of both cores is about 2.5 2m
- the distance between the centers of the cores is about 3.8 ⁇ m
- the core is about 3.8 ⁇ m.
- the relative refractive index difference between the part and the cladding is about 0.7%, and the wavelength used is 1.55 ⁇ m.
- the electric field intensity distribution of the propagation mode of this polarization-maintaining optical fiber is a perfect circle as shown in Fig. 13.
- l Ze e is the base of the natural logarithm of the beak power (P o).
- the cross-sectional shape was a long ellipse with a major axis of about 8 ⁇ m and a minor axis of about 4> ⁇ .
- the polarization-maintaining optical fiber was cut off by about 5 m, and each cut end was heated at about 650 ° C. by high-frequency arc discharge over a length of about 7 mm. This heating was intermittently performed every 10 seconds, and the cross-sectional shape that was 1 / e of the above-mentioned beak power was measured, and the change in the cross-sectional shape due to the heating time was determined.
- FIG. 15 is a graph showing the results.
- the solid line shows the change in the major axis of the ellipse
- the broken line shows the change in the minor axis. From this graph, it can be seen that the major axis and the minor axis were almost the same at a heating time of 60 seconds, and the ellipse changed to a circle with a diameter of about 15 m.
- connection loss was 0.3 dB.
- a similar polarization-maintaining optical fiber was fusion-spliced so that its polarization planes crossed at 45 degrees, and then 5 mm on each side of the joint at a point of 600 ° C at 160 ° C. After heating for a second, the splice loss was 0.3 dB.
- the method of heating the vicinity of the connection point at the time of fusion splicing according to the present invention is also effective for connecting another polarization maintaining optical fiber having a core to which germania is added.
- connection method of the polarization maintaining optical fiber of the present invention the elliptical electric field component
- the mode field shape in the connection between the polarization maintaining optical fibers having the cloth shape can be eliminated, and the connection loss can be reduced.
- the rare earth-doped preserving optical fiber is obtained by adding a rare earth element to the core portion or a portion sandwiched between the core portions of the polarization maintaining optical fiber of the present invention.
- FIGS. 16 (a) to 16 (f) show examples of the rare earth-doped polarization maintaining optical fiber (hereinafter abbreviated as REDPMF) of the present invention.
- REDPMF rare earth-doped polarization maintaining optical fiber
- the REDPMF shown in Fig. 16 (a) has a clad 28 made of low refractive index glass with a circular cross section and two cores 29 made of high refractive index glass with a circular cross section. 9b.
- the cores 29a and 29b pass through the central axis 0 of the optical fiber and are arranged opposite to each other in a plane symmetrical manner with respect to one plane along the axial direction.
- the cores 29a and 29b have the same diameter and the same diameter.
- the diameter is about 2 to 2 depending on the wavelength used and the relative refractive index difference between the cores 29a and 29b. It is about 10 m.
- the distance between one core portion 29a and the other core portion 29b is determined by the dimension 1 between the central portions of the core portions 29a and 29b shown in FIG. 16 (a). Is selected in the range of about 0.5 to 2.5 times the diameter of the core 29.
- the relative refractive index difference between the core portions 29a and 29b and the cladding 28 is 0.15 to 3.0%.
- the glass forming the clad 28 pure quartz, fluorine-doped quartz or the like is used, and as the glass forming the core portions 29a, 29b,..., germanium oxide doped quartz, pure quartz, such as oxide Li Ndobu quartz, N d, E r, glass rare earth element and optionally a 1 2 03 such as S m is added is used.
- the outer diameter of the clad 28 is usually 125 mm, but a value such as 80 mm may be selected as necessary.
- the addition amount of the rare earth element is 300 to 200 ppm (weight), and the addition amount of A1203 is about 5 to 15 times the addition amount of the rare earth element.
- the example shown in Fig. 16 (b) is different from the example shown in Fig. 16 (a) in that both core portions 29a and 29b have a rectangular cross-sectional shape. Square as a square It may be rectangular or rectangular. The long sides of the key sections 29a and 29b are about 2 to 10 ⁇ m, the short sides are 2 to lp ⁇ m, and the interval 1 is about 0.5 to 2 times the short side. '.
- the one shown in Fig. 16 (c) consists of four rectangular cores 29a, 29b, 29c, and 29d, which propagate one basic mode as a whole of these four cores. It does. In the examples shown in FIGS.
- the cross-sectional shape of the clad 28 is elliptical, and its longitudinal direction and the core portions 29 a, 2
- the arrangement direction of 9 b (29 c, 29 d) is the same.
- Figures 16 (b) to (f), but the cores 29a, 29b, 29c ... are similar to the addition of rare earth elements and, if necessary, AI2O3. is there.
- Fig. 17 schematically shows the refractive index distribution of the polarization-maintaining optical fiber shown in Fig. 16 (b) and the mode distribution of the basic mode propagating through the cores 29a and 29b.
- (A) is the refractive index distribution in the X-axis direction
- (b) is the refractive index distribution in the y-axis direction
- (c) is the refractive index distribution in the y'-axis direction
- (d) is the mode distribution in the X-axis direction
- (e ) Indicates the mode distribution in the y-axis direction.
- the mode distribution in the X-axis direction extends to the part of the clad 28 between the cores 29a and 29b, which is quite different from the refractive index distribution.
- the mode distribution in the y-axis direction is almost the same as that of a normal single-mode fiber.
- the mode distribution in the X-axis direction and the mode distribution in the y-axis direction are different from each other, indicating non-axial symmetry.
- a birefringence index B g of the waveguide structure is generated, and a polarization maintaining property is generated.
- the melt spinning is performed.
- the non-axially symmetric internal stress that occurs at the core portions 29a and 29b themselves causes the stress-induced birefringence Bs to appear due to the internal stress, which also indicates the polarization retention.
- the stress-induced birefringence Bs is added to the birefringence Bg of the waveguide structure, the birefringence B as a whole becomes large.
- FIGS. 18 (a) to 18 (d) show other examples of the REDPMF of the present invention.
- three core portions 32a, 32b, 32c ... are provided.
- the above-mentioned odd number is different from that shown in FIG.
- the one at the center is located on the central axis 0 of the optical fiber, and the other cores are at the center.
- rare earth elements are added to these core portions 3'2a, 32b, 32c ... together with A1203 as necessary.
- the optical power is also transmitted to the part of the clad in the low g-fold rate region sandwiched between 29a and 29b. It is known that in a conventional optical amplifier using a rare-earth-doped optical fiber, it is better to limit the region to which the rare-earth element is added to a region having a high optical power. From this, in the REDPMF of the present invention, a mode in which a rare earth element is added together with AI02O3 to the portions of the clad in the plurality of cores as necessary is considered.
- FIGS. 19 (a) and (b) show examples of the case where the region to which the rare earth element is added is a portion of the cladding sandwiched between the cores, and the hatched portions 33a, 3b 3 b,
- FIG. 19 (a) The one shown in FIG. 19 (a) is obtained by adding a rare earth element to a substantially circular portion 33a sandwiched between two circular core portions 32a and 32b.
- Fig. 19 (b) shows two substantially circular parts 33a, 33b sandwiched between three core parts 32a, 32b, 32c with rare earth elements added. It is.
- the core portions 32a, 32b, 32c ... and the portions 33 of the cladding sandwiched between these core portions 32a, 32b, 32c ... Both a, 33b and so on may be added with a rare earth element and, if necessary, aluminum oxide.
- FIG. 20 shows an example of an optical amplifier using the REDPMF of the present invention.
- reference numeral 35 denotes an excitation light source
- 36 denotes a first optical power bra
- 37 denotes 11 £ 0 ⁇ 1 ⁇
- 3 8 is the second power bra.
- the signal light is input to the first port of the first force blur 36
- the pump light from the pump light source 35 is input to the second port of the first force blur 36.
- the signal light and the pump light are output from the third port of the first coupler 36 and input to the REDMPF.
- the signal light and the pump light amplified by the REDPMF 37 are input to the first port of the second force blur 38, where the signal light and the pump light are split and amplified from the third port.
- the signal light is output from the fourth port, and the remaining pump light is output.
- FIG. 21 shows an example of a laser oscillator using the REDPMF of the present invention.
- reference numeral 39 denotes a ring-type resonator formed by winding REDPMF
- 40 denotes an isolator
- 41 denotes a pump.
- the light source, 42 is a wavelength-multiplexed first force bra
- 43 is a small-coupling plastic second force bra.
- Excitation light from the excitation light source 41 is coupled to the ring resonator 39 from the first force brass 42 and input, and oscillates here.
- the oscillated light is output from the ring resonator 39 via the second force blur 43.
- Oscillation light is not coupled in the first force blur 42, and about 1 to 10% of the oscillation light is coupled to the second force blur 43 and output to the outside.
- a columnar glass rod serving as a clad is prepared.
- This glass rod is made of pure quartz, fluorine-doped quartz, or the like, and is manufactured by a well-known VAD method or the like.
- a plurality of holes into which the glass rod as the core is inserted are mechanically formed in the glass rod, and the inner surface of the hole is polished. The positions of the holes are determined so as to be similar to the obtained optical fiber.
- a glass rod serving as a core is prepared.
- This glass rod is first made of a soot made of germanium oxide dove quartz, pure quartz, etc. by the VAD method. After forming a foam, the soot foam is immersed in a rare earth element solution such as an aqueous solution of hydrochloric acid of ErC Is to impregnate the rare earth element, and then a transparent vitrified turf is used.
- a rare earth element solution such as an aqueous solution of hydrochloric acid of ErC Is to impregnate the rare earth element, and then a transparent vitrified turf is used.
- the outer diameter of this glass rod is naturally slightly smaller than the inner diameter of the above-mentioned six.
- the above-mentioned lath rod serving as the core is inserted into the hole of the glass port serving as the clat, and the entire body is cobrased by heating> as the base material.
- the desired REDPMF can be obtained.
- a glass serving as a clad may be further formed on the outer peripheral surface of the base material by an external method or the like, and then melt-spun.
- a plurality of glass rods serving as a core part are arranged at predetermined intervals and fixed at both ends thereof.
- a glass sheet to be used as a head is deposited, and the glass material is made into a transparent glass to prepare a base material, and then the base material is melt-spun.
- soot is deposited between a plurality of glass rods serving as the core when the glass soot serving as the clad is deposited, the soot is immersed in the rare earth element solution as described above and the soot is soaked.
- the above-mentioned low refractive index region between the cores can be obtained.
- REDPMF in which rare earth elements are added to the cladding can be obtained.
- a glass rod serving as a core is made of a glass rod to which a rare earth element is added, REDPMF in which a rare earth element is added to the core and a portion of the cladding sandwiched between the core and the core is obtained.
- the present invention it is possible to obtain a REDPMF having good polarization maintaining characteristics, an excellent optical amplification function, and easy polarization axis alignment at the time of fusion splicing. Also, since the structure is simple, it is easy to manufacture and can be supplied at low cost. Furthermore, an optical amplifier and a laser oscillator that output output light with good polarization characteristics can be obtained at low cost.
- the VAD method to prepare the Sioux bets Purifu Omu of G e 0 2 doped quartz glass Amount of G e 0 2 of the Sue Topuri form is about 1 5 mole%, quartz glass And a relative refractive index difference of 1.5%.
- This soot preform contains an aqueous solution of erbium chloride and an aluminum chloride solution, and is then dehydrated and turned into a transparent glass.
- the amount of erbium added is 800 ppm, and the amount of aluminum added is 90%.
- a 0 ppm glass rod was made.
- a load of fluorine-doped quartz glass was prepared by the VAD method.
- the difference in the relative refractive index between this rod and quartz glass was 10.4%.
- This intermediate base material is heated and stretched, and a quartz glass serving as a clad is formed on the outer surface of the intermediate base material by a known external method to form a base material, which is melt-spun and shown in FIG. 16 (a).
- a REDPMF with the structure shown was obtained.
- the one of the core diameter of the REDPMF is 2.
- the REDPMF Using this REDPMF, an optical amplifier as shown in FIG. 20 was produced.
- the length of the REDPMF is 30 m
- the wavelength of the pump light is 0.98 m
- the output is 30 mW
- a signal with a wavelength of 1.553 m is input.
- An optical amplification operation of 5 dB and a noise figure of 3 dB was performed.
- Ge02-doped quartz glass rods were prepared by the VAD method. G e 0 2 amount of this product Ri 1 5 mol% der, the relative refractive index difference between the quartz glass was 1. 5%. This glass rod was heated and stretched to obtain a glass rod serving as a core.
- a pure silica glass preform was prepared by the VAD method, and erbium and aluminum were added to this preform in the same manner as in Example 1, and the amount of erbium added was about 100 O
- a glass rod with a ppm and aluminum content of about 10,000 ppm was prepared.
- one glass rod with erbium / aluminum is sandwiched between two glass rods to be the core part, arranged in a line, and fixed at both ends.
- This mother material was melt spun and the core material was inserted into two core parts 32a and 32b as shown in Fig. 19 (a). REDPMF with erbium added to it.
- the center-to-center distance of the core is 2.9 m
- the cutoff wavelength of the secondary mode group is about 1.2 ⁇ m
- a polarization maintaining fiber is produced at a wavelength of 1.5 / m.
- the refractive index in the erbium-doped region increased slightly due to the addition of aluminum, but no effect on the polarization maintaining performance was observed. '
- a laser oscillator as shown in Fig. 21 was created.
- a wavelength multiplexing type power blur of 1.48> m and 1.55 / zm for the first power blur 42 a laser with a wavelength of 1.53 m was obtained at an excitation light input of about 5 OmW. The light was obtained at an output of about 5 mW c
- the polarization maintaining optical fiber of the present invention can be used for an optical fiber sensor and the like. Then, by adding a rare earth element to the optical waveguide portion of the polarization maintaining optical fiber, it can be used for an optical amplifier and a laser oscillator. In addition, two or more of the above-mentioned polarization-maintaining optical fibers are attached to each other and heated, fused, and stretched to maintain the polarization of propagating light, thereby splitting and merging light among a plurality of optical fibers. It can be used for an optical fiber power bra that performs demultiplexing and multiplexing.
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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EP94907683A EP0637762B1 (en) | 1993-02-25 | 1994-02-24 | Polarized wave holding optical fiber, production method therefor, connection method therefor, optical amplifier, laser oscillator and polarized wave holding optical fiber coupler |
DE69424606T DE69424606T2 (de) | 1993-02-25 | 1994-02-24 | Polarisationserhaltende optische faser, herstellungsverfahren dafür, verbindungsverfahren dafür, optischer verstärker, laseroszillator und polarisationserhalter optischer faserkoppler |
US08/318,848 US5689578A (en) | 1993-02-25 | 1994-02-24 | Polarized wave holding optical fiber, production method therefor, connection method therefor, optical amplifier, laser oscillator and polarized wave holding optical fiber coupler |
Applications Claiming Priority (12)
Application Number | Priority Date | Filing Date | Title |
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JP3710293 | 1993-02-25 | ||
JP5/37102 | 1993-02-25 | ||
JP5/162934 | 1993-06-30 | ||
JP16293493 | 1993-06-30 | ||
JP5/163583 | 1993-07-01 | ||
JP16358393 | 1993-07-01 | ||
JP5/183082 | 1993-07-23 | ||
JP18308193 | 1993-07-23 | ||
JP5/183083 | 1993-07-23 | ||
JP18308393 | 1993-07-23 | ||
JP18308293 | 1993-07-23 | ||
JP5/183081 | 1993-07-23 |
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PCT/JP1994/000300 WO1994019714A1 (en) | 1993-02-25 | 1994-02-24 | Polarized wave holding optical fiber, production method therefor, connection method therefor, optical amplifier, laser oscillator and polarized wave holding optical fiber coupler |
Country Status (4)
Country | Link |
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US (1) | US5689578A (ja) |
EP (1) | EP0637762B1 (ja) |
DE (1) | DE69424606T2 (ja) |
WO (1) | WO1994019714A1 (ja) |
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US20200400877A1 (en) * | 2019-06-20 | 2020-12-24 | Yangtze Optical Fibre And Cable Joint Stock Limited Copmany | Array-type polarization-maintaining multi-core fiber |
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Also Published As
Publication number | Publication date |
---|---|
EP0637762A1 (en) | 1995-02-08 |
US5689578A (en) | 1997-11-18 |
DE69424606D1 (de) | 2000-06-29 |
DE69424606T2 (de) | 2001-01-25 |
EP0637762A4 (en) | 1995-07-05 |
EP0637762B1 (en) | 2000-05-24 |
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