CN102262263B - Optical fibre with multiple-sector fiber core at periphery of multiple-sector area of circular fiber core, and fabrication method thereof - Google Patents

Abstract

The invention relates to a multi-sector core optical fiber around a circular core multi-sector area and a manufacturing method thereof, belonging to the fields of high-power broadband fiber lasers and special optical fibers. It overcomes the limited optical power of single-core multi-doped rare earth ion region double-clad optical fiber and the limited core diameter of block-clad optical fiber. The optical refractive index, radius and radian of the first to N sector-shaped rare earth ion-doped regions are all equal to form a complete circular fiber core; an integer of 3≤N≤9; the same radius and radian are evenly distributed around the circular fiber core in the inner cladding The first to M fan-shaped cores of α; an integer of N≤M≤32; π/2M≤α≤2π/M; the distance between the vertices of the first to M fan-shaped cores and the outer circle of the circular core is equal, The rare earth ion type sets of the circular core and the first to Mth fan-shaped cores are equal. The manufacturing method is as follows: making circular fiber core thin rods and fan-shaped fiber core thin rods, and organizing them into the optical fiber. The optical fiber has a high yield rate, and the fusion splicing loss with the single-mode optical fiber is small; and single-mode operation with a large mode field area is realized.

Description

Peripheral multi-sector core optical fiber of circular core multi-sector area and manufacturing method thereof

technical field

The invention relates to a circular core multi-sector peripheral multi-sector fiber core optical fiber and a manufacturing method thereof, belonging to the fields of high-power broadband optical fiber amplifiers, lasers and special optical fibers.

Background technique

Rare earth-doped fiber amplifiers or lasers use ion fibers doped with rare earth elements (Nd, Sm, Ho, Er, Pr, Tm, Yb, etc.), and use the stimulated emission mechanism to achieve direct amplification of light.

The absorption cross-section and emission cross-section of each rare earth element are different, resulting in different working wavelengths of the corresponding optical fibers. For example, the working wavelength of neodymium-doped fiber is 1000-1150nm, 1320-1400nm; the working wavelength of erbium-doped fiber is 550nm, 850nm, 980-1000nm, 1500-1600nm, 1660nm, 1720nm, 2700nm; the working wavelength of ytterbium-doped fiber is 970-1040nm; The working wavelength of thorium fiber is 455nm, 480nm, 803-825nm, 1460-1510nm, 1700-2015nm, 2250-2400nm; the working wavelength of praseodymium-doped fiber is 490nm, 520nm, 601-618nm, 631-641nm, 707-725nm, 880-886nm , 902-916nm, 1060-1110nm, 1260-1350nm; holmium-doped fiber working wavelengths are 550nm, 753nm, 1380nm, 2040-2080nm, 2900nm. The working wavelength of samarium-doped fiber is 651nm,

Rare earth ions doped with different glass substrates have different gain bandwidths and properties. For example, the 1500nm gain half-wave spectral width of erbium-doped fiber with pure silica fiber glass matrix is 7.94nm, while the 1500nm gain half-wave spectral width of erbium-doped fiber with aluminum phospho-silicate fiber glass matrix is 43.3nm[W.J.Miniscalco.Optical and electronic properties of rare-earth ions in glasses in rare-earth doped fiber lasers and amplifier. New York: Marcel Dekker. 2001, pp: 17-112]. Existing double-clad optical fibers are either single-doped rare earth or double-doped rare earth. Even the double-doped rare earth fiber uses the different absorption cross-sections of the two doped rare earth elements for the pump source, and the interaction between the energy levels of the two elements that are very close to each other, so that one doped rare earth element absorbs the pump power, and the other The purpose of stimulated amplification of elements, such as erbium-ytterbium co-doped fiber. Therefore, the bandwidth of the existing double-clad optical fiber amplification signal is usually only tens of nm. When it is necessary to amplify signals of different wavelengths and the wavelength interval exceeds 100nm, it is necessary to configure different double-clad optical fibers separately, and then combine the signals. Complicated and costly.

Chinese Patent No. 200910236162.4 proposes a single-core multi-rare-earth-doped double-clad fiber, which can amplify multi-band optical signals or be a gain medium for multi-band lasers; however, it is subject to nonlinearity, structural elements and diffraction The limitation of the limit, the limited optical power, the single-core continuous wave damage threshold is about 1W/m ² [J.Nilsson, JKSahu, Y.Jeong, WAClarkson, R.Selvas, ABGrudinin, andS.U.Alam,"High Power Fiber Lasers: New Developments", Proceedings of SPIEVol.4974, 50-59(2003)], the risk of optical damage has become a major challenge for the realization of high-power single-mode fiber lasers. In addition to optical damage, the heat generated by high-power light is also Can damage the fiber and even eventually melt the core.

Multi-core fiber lasers achieve single-mode output, which has been verified. The multicore fiber used in the literature has an effective mode area of 465 μm ² [Vogel, Moritx M, Abdou-Ahmed, Marwan, Voss, Andreas, Graf, Thomas, "Very large mode area single-mode multicore fiber", Opt. Lett. 34(18), 2876-2878(2009)]. However, the multi-core fiber used in this single-mode laser requires precise design of the core diameter of the fiber core and the distance between adjacent fiber cores. The allowable error of the distance between the fiber cores is small, and the mass production yield Low.

Block-clad fiber is a new type of fiber. Selecting specific fiber parameters can achieve single-mode operation [A.Yeung, K.S.Chiang, V.Rastogi, P.L.Chu, and G.D.Peng, "Experimental demonstration of single-mode operation of large -core segmented cladding fiber, "in Optical Fiber Communication Conference, Technical Digest (CD) (Optical Society of America, 2004), paper ThI4.]. This kind of fiber, whose specific structure is to increase the loss outside the fundamental mode, realizes single-mode operation in the fiber with a core diameter of 50 microns, but its power increase is limited by the radius of the core layer.

Contents of the invention

In order to overcome the defects of the existing large-mode-field single-mode multi-core optical fiber with low batch production yield, limited core diameter of block-clad optical fiber, and limited optical power of single-core multi-doped rare earth ion region double-clad optical fiber, a new method was proposed. A circular core multi-sector peripheral multi-sector core fiber and a preparation method thereof.

The purpose of the present invention is achieved through the following technical solutions:

The multi-sector core fiber around the circular core multi-sector area includes a core, an inner cladding and an outer cladding.

The optical refractive index, radius and radian of the first to Nth fan-shaped rare earth ion-doped regions are all equal to form a complete circular fiber core; the radius of the circular fiber core is 2-20 microns; an integer of 3≤N≤9.

The first to Mth fan-shaped cores with the same radius and the same radian are evenly distributed around the circular core in the inner cladding; the integer of N≤M≤32.

The radius of the first fan-shaped fiber core, the second fan-shaped fiber core, ..., the M-th fan-shaped fiber core is 20-200 microns, and the radian is α, π/2M≤α≤2π/M;

The apexes of the first fan-shaped core, the second fan-shaped core, .

The optical refractive index of the circular core and the first to Mth fan-shaped cores are equal, and the optical refractive index is greater than that of the inner cladding, and the optical refractive index of the inner cladding is greater than that of the outer cladding.

The types of doped rare earth ions in the first to N sector-shaped rare earth ion doped regions are not all the same; the doped rare earth ion types include neodymium ions, erbium ions, ytterbium ions, thorium ions, praseodymium ions, holmium ions, samarium ions, neodymium ytterbium co-doped ions or Erbium-ytterbium co-doped ions.

The types of rare earth doped ions in the first to Mth fan-shaped cores are not all the same, and the set of rare earth ion types in the first to Mth fan-shaped cores is equal to the set of rare earth ion types in the first to Nth fan-shaped rare earth ion-doped regions.

A method for making a multi-sector core optical fiber at the periphery of a circular core multi-sector area comprises the following steps:

Step 1 Fabrication of a circular core thin rod containing an annular cladding region

Select N rare earth ion-doped optical fiber preforms with the same core radius and the same optical refractive index; an integer of 3≤N≤9;

removing part of the cladding of the N optical fiber prefabricated rods, so that the thickness of the remaining cladding is equal;

Drawing N optical fiber preform rods from which part of the cladding has been removed into thin rods with the core radius equal to the cladding thickness;

Process the above N optical fiber preform rods into N fan-shaped thin rods with the same radius and same radian, and the radian of each fan-shaped thin rod is 2π/N; N fan-shaped thin rods form a complete circle, forming a ring-shaped cladding Circular core thin rods in the area;

Step 2 Make fan-shaped fiber core rods

Select M doped rare earth ion optical fiber preforms with the same core radius and optical refractive index; the integer of N≤M≤32, the optical refractive index of the selected M optical fiber preform cores is the same as the N used in step one The optical refractive index of the core layer of the optical fiber preform is equal;

Remove the cladding of the M optical fiber prefabricated rods, leaving only the core layer;

drawing the above M optical fiber preforms into thin rods with equal radii;

Then process the above M optical fiber preform rods into M fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is α, π/2M≤α≤2π/M;

Step 3: Make a circular core multi-sector peripheral multi-sector core fiber

The circular fiber core thin rod containing the annular cladding area and the M fan-shaped fiber core thin rods of step two are organized to complete the step one, put on a quartz tube, and the optical refractive index in the gap is lower than that of the fan-shaped thin rod, but lower than that of the fan-shaped thin rod. The quartz tube is filled with thin quartz rods with high optical refractive index; it is drawn into a circular core multi-sector peripheral multi-sector core fiber.

The beneficial effects of the present invention are specifically as follows:

The multi-sector core fiber around the circular core multi-sector area does not require consistency, which improves the yield of the fiber, and uses a single-mode circular core instead of using a large-diameter core like a segmented cladding fiber, which reduces Splicing loss with single-mode fiber; there is a distance between the single-mode circular core and multiple fan-shaped cores, on the one hand, it increases the coupling with each other, and realizes single-mode operation with a large mode field area; on the other hand, it is conducive to heat dissipation and protects the optical fiber.

Description of drawings

Fig. 1 is a cross-sectional view of a multi-sector core fiber around a circular core multi-sector area with three sector-shaped rare earth ion-doped areas and three sector-shaped cores.

Fig. 2 is a cross-sectional view of a multi-sector core fiber around a circular core multi-sector area with four sector-shaped rare earth ion-doped areas and six sector-shaped cores.

Fig. 3 is a cross-sectional view of a multi-sector core fiber around a circular core multi-sector area with six sector-shaped rare earth ion-doped areas and eighteen sector-shaped cores.

Fig. 4 is a cross-sectional view of a multi-sector core fiber around a circular core multi-sector area with nine sector-shaped rare earth ion-doped regions and thirty-two sector-shaped cores.

Detailed ways

The present invention does not relate to the manufacture of rare earth ion-doped fiber core optical fiber prefabricated rods, which are patented or documented technologies.

The present invention will be further described below in conjunction with the accompanying drawings.

Embodiment one

Three fan-shaped rare earth ion-doped regions (11, 12, 13) and three fan-shaped cores (21, 22, 23) circular core multi-sector peripheral multi-sector core fiber, as shown in Figure 1;

The first sector-shaped neodymium-doped ion region 11, the second sector-shaped erbium-doped ion region 12, and the third sector-shaped ytterbium-doped ion region 13 have the same optical refractive index, radius and radian, forming a complete circular fiber core; the radius of the circular fiber core is 2 microns;

Three fan-shaped cores with the same radius and the same radian are evenly distributed around the circular core in the inner cladding 3; the radii of the first fan-shaped core 21, the second fan-shaped core 22, and the third fan-shaped core 23 are all 20 microns, The radians are all α=π/6, and the rare earth ions doped in the first fan-shaped fiber core 21, the second fan-shaped fiber core 22, and the third fan-shaped fiber core 23 are erbium ions, neodymium ions, and ytterbium ions respectively;

The first fan-shaped core 21, the second fan-shaped core 22, and the third fan-shaped core 23 are at the same distance from the outer circle of the circular fiber core, and the distances are all 2 microns;

The optical refractive index of the circular core, the first to the third fan-shaped core 21, 22, 23 is equal, the optical refractive index of the first fan-shaped fiber core 21 is greater than the optical refractive index of the inner cladding 3, and the optical refractive index of the inner cladding 3 is greater than The optical refractive index of the outer cladding 4.

A method for making a circular core multi-sector peripheral multi-sector core fiber with three sector-shaped rare earth ion-doped regions (11, 12, 13) and three sector-shaped cores (21, 22, 23), comprising the following steps:

Step 1 Fabrication of a circular core thin rod containing an annular cladding region

Choose three erbium-doped optical fiber preforms, neodymium-doped optical fiber preforms, and ytterbium-doped optical fiber preforms with the same core radius and optical refractive index;

Part of the cladding of the three optical fiber preformed rods is removed by grinding, so that the thickness of the remaining cladding is equal;

Draw the three optical fiber preform rods with part of the cladding removed into thin rods with the same core radius and cladding thickness, the core radius is 2mm, and the cladding thickness is 2mm;

Using the method of laser cutting, the above three optical fiber preforms are processed into three fan-shaped thin rods with the same radius and the same radian, and the radian of each fan-shaped thin rod is 2π/3; the three fan-shaped thin rods form a complete circle, Thin rods forming a circular core with an annular cladding region

Step 2 Make fan-shaped fiber core rods

Select erbium-doped optical fiber preforms, neodymium ion optical fiber preforms, and ytterbium ion optical fiber preforms with the same core radius and optical refractive index. The optical refractive index of the core layer of the three optical fiber preforms selected is the same as that of the three optical fibers used in step 1. The optical refractive index of the preform core layer is equal;

The cladding of the three optical fiber prefabricated rods is removed by hydrofluoric acid etching, leaving only the core layer;

Draw the above three optical fiber preforms into thin rods with the same radius, the radius is 20mm;

Then use the method of laser cutting to process the above three optical fiber preforms into three fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is π/6;

Step 3: Make a circular core multi-sector peripheral multi-sector core fiber

Organize the circular core thin rods and three fan-shaped fiber core thin rods in the annular cladding area that have completed steps 1 and 2, put on a quartz tube, and use an optical refractive index lower than that of the fan-shaped thin rods but higher than that of the quartz tube at the gap. Filled with thin quartz rods with high optical refractive index; drawn into circular core multi-sector peripheral multi-sector core fiber.

Embodiment two

Four fan-shaped rare earth ion-doped regions (11, 12, 13, 14) and six fan-shaped cores (21, 22, 23, 24, 25, 26) round core multi-sector core fiber at the periphery of the multi-sector area, as shown in the figure 2 shown;

The first sector-shaped neodymium-doped ion region 11, the second sector-shaped erbium-doped ion region 12, the third sector-shaped ytterbium-doped ion region 13, and the fourth sector-shaped erbium-doped ion region 14 have the same optical refractive index, radius and radian, forming a complete circle Fiber core; the radius of the circular fiber core is 5 microns;

Six fan-shaped cores with the same radius and the same arc are evenly distributed around the circular core in the inner cladding 3; the radii of the first fan-shaped core 21, the second fan-shaped core 22, ..., the sixth fan-shaped core 26 is 60 microns, and the radian is α=π/6, the rare earth ions doped in the first fan-shaped core 21, the second fan-shaped core 22, ..., the sixth fan-shaped core 26 are erbium ions, neodymium ions, ytterbium ions, respectively. ions, erbium ions, neodymium ions, ytterbium ions;

The first fan-shaped core 21, the second fan-shaped core 22, ..., the sixth fan-shaped core 26 are at the same distance from the outer circle of the circular core, and the distances are all 4 microns;

The optical refractive index of the circular fiber core, the first fan-shaped fiber core 21, the second fan-shaped fiber core 22, ..., the sixth fan-shaped fiber core 26 is equal, and the optical refractive index of the first fan-shaped fiber core 21 is greater than that of the inner cladding 3. Refractive index, the optical refractive index of the inner cladding layer 3 is greater than the optical refractive index of the outer cladding layer 4 .

Manufacturing method of circular core multi-sector peripheral multi-sector core fiber with four fan-shaped rare earth ion-doped regions (11, 12, 13, 14) and six fan-shaped cores (21, 22, 23, 24, 25, 26) , including the following steps:

Step 1 Fabrication of a circular core thin rod containing an annular cladding region

Select four erbium-doped optical fiber preforms, neodymium-doped optical fiber preforms, ytterbium-doped optical fiber preforms, erbium-doped optical fiber preforms, neodymium-doped optical fiber preforms, and ytterbium-doped optical fiber preforms with the same core radius and optical refractive index. Ion fiber preform;

Part of the cladding of the four optical fiber prefabricated rods is removed by hydrofluoric acid etching, so that the thickness of the remaining cladding is equal;

Draw the four optical fiber prefabricated rods with part of the cladding removed into thin rods with the same core radius and cladding thickness, the core radius is 5mm, and the cladding thickness is 4mm;

Using the method of laser cutting, the above four optical fiber preform rods are processed into four fan-shaped thin rods with the same radius and the same radian, and the radian of each fan-shaped thin rod is π/2; the four fan-shaped thin rods form a complete circle , constituting a circular core thin rod with an annular cladding region

Step 2 Make fan-shaped fiber core rods

Choose erbium-doped optical fiber preforms, neodymium ion optical fiber preforms, ytterbium ion optical fiber preforms, erbium-doped optical fiber preforms, neodymium ion optical fiber preforms, and ytterbium ion optical fiber preforms with the same core radius and optical refractive index, here The optical refractive index of the optical fiber preform core layer is equal to the optical refractive index of the optical fiber preform core layer adopted in step one;

The cladding of the six optical fiber prefabricated rods was removed by hydrofluoric acid etching, leaving only the core layer;

Draw the above six optical fiber preforms into thin rods with the same radius, the radius is 60mm;

Then use the method of laser cutting to process the above six optical fiber preforms into six fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is π/6;

Step 3: Make a circular core multi-sector peripheral multi-sector core fiber

The circular core thin rods and six fan-shaped fiber core thin rods in the annular cladding area that have completed steps 1 and 2 are organized, put on a quartz tube, and the optical refractive index is lower than that of the fan-shaped thin rods but higher than that of the quartz tube at the gap. Filled with thin quartz rods with high optical refractive index; drawn into circular core multi-sector peripheral multi-sector core fiber.

Embodiment three

Six fan-shaped rare earth ion-doped regions (11, 12, ..., 16) and eighteen fan-shaped cores (21, 22, ..., 218) circular core multi-sector peripheral multi-sector core fiber, such as As shown in Figure 1;

The first sector-shaped neodymium-doped ion region 11, the second sector-shaped holmium-doped ion region 12, the third sector-shaped erbium-doped ion region 13, the fourth sector-shaped ytterbium-doped ion region 14, the fifth sector-shaped neodymium-ytterbium co-doped ion region 15, the sixth sector The optical refractive index, radius and radian of the samarium-doped region 16 are all equal, forming a complete circular fiber core; the radius of the circular fiber core is 12 microns;

Eighteen fan-shaped cores with the same radius and same radian are evenly distributed around the circular core in the inner cladding 3; the first fan-shaped core 21, the second fan-shaped core 22, ..., the eighteenth fan-shaped core 18 The radii are all 100 microns, and the radians are all π/10. The rare earth ions doped in the first fan-shaped fiber core 21, the second fan-shaped fiber core 22,..., and the eighteenth fan-shaped fiber core 18 are neodymium-doped ions and holmium-doped ions respectively. Ions, erbium-doped ions, ytterbium-doped ions, neodymium-ytterbium co-doped ions, samarium-doped ions, neodymium-doped ions, holmium-doped ions, erbium-doped ions, ytterbium-doped ions, neodymium-ytterbium co-doped ions, samarium-doped ions, neodymium-doped ions, Holmium-doped ions, erbium-doped ions, ytterbium-doped ions, neodymium-ytterbium co-doped ions, samarium-doped ions;

The distance between the apex of the first fan-shaped core 21, the second fan-shaped core 22, ..., the eighteenth fan-shaped core 18 and the outer circle of the circular fiber core is equal, and the distances are all 10 microns;

The optical refractive indices of the circular core, the first fan-shaped core 21, the second fan-shaped core 22, ..., the eighteenth fan-shaped core 18 are equal, and the optical refractive index of the first fan-shaped core 21 is greater than that of the inner cladding 3 The optical refractive index, the optical refractive index of the inner cladding layer 3 is greater than the optical refractive index of the outer cladding layer 4 .

Fabrication of circular core multi-sector peripheral multi-sector core fiber with six sector-shaped rare earth ion-doped regions (11, 12, ..., 16) and eighteen sector-shaped cores (21, 22, ..., 218) method, including the following steps:

Step 1 Fabrication of a circular core thin rod containing an annular cladding region

Select six neodymium-doped optical fiber preforms, holmium-doped optical fiber preforms, erbium-doped optical fiber preforms, ytterbium-doped optical fiber preforms, neodymium-ytterbium co-doped optical fiber preforms, and doped optical fiber preforms with the same core radius and optical refractive index. Samarium ion optical fiber preform;

Part of the cladding of the six optical fiber preformed rods is removed by grinding, so that the thickness of the remaining cladding is equal;

Draw the six optical fiber preform rods with part of the cladding removed into thin rods with the same core radius and cladding thickness, the core radius is 12mm, and the cladding thickness is 10mm;

Using the method of laser cutting, the above four optical fiber preforms are processed into six fan-shaped thin rods with the same radius and the same radian, and the radian of each fan-shaped thin rod is π/3; the six fan-shaped thin rods form a complete circle , constituting a circular core thin rod with an annular cladding region

Step 2 Make fan-shaped fiber core rods

Select neodymium-doped optical fiber preforms, holmium-doped optical fiber preforms, erbium-doped optical fiber preforms, ytterbium-doped optical fiber preforms, neodymium-ytterbium co-doped optical fiber preforms, samarium-doped optical fiber preforms with the same core radius and optical refractive index Ion optical fiber preform, neodymium-doped optical fiber preform, holmium-doped optical fiber preform, erbium-doped optical fiber preform, ytterbium-doped optical fiber preform, neodymium-ytterbium co-doped ion optical fiber preform, samarium-doped optical fiber preform, Neodymium ion optical fiber preform, holmium-doped optical fiber preform, erbium-doped optical fiber preform, ytterbium-doped optical fiber preform, neodymium-ytterbium co-doped ion optical fiber preform, samarium-doped optical fiber preform, the fiber preform core layer here The optical index of refraction is equal to the optical index of refraction of the optical fiber preform core layer adopted in step one;

The cladding of eighteen optical fiber prefabricated rods was removed by hydrofluoric acid etching, leaving only the core layer;

Draw the above eighteen optical fiber preforms into thin rods with the same radius, the radius is 100mm;

Then use the method of laser cutting to process the above eighteen optical fiber preforms into eighteen fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is π/10;

Step 3: Make a circular core multi-sector peripheral multi-sector core fiber

The circular core thin rods and eighteen fan-shaped fiber core thin rods in the annular cladding region that have completed steps one and two are organized, put on a quartz tube, and the optical refractive index in the gap is lower than that of the fan-shaped thin rods but higher than that of quartz. The tube is filled with thin quartz rods with high optical refractive index; it is drawn into a circular core multi-sector peripheral multi-sector core fiber.

Embodiment Four

Nine sector-shaped rare earth ion-doped regions (11, 12, ..., 19) and thirty-two sector-shaped cores (21, 22, ..., 232) circular core multi-sector-shaped peripheral multi-sector core fiber optics, As shown in Figure 1;

The first sector-shaped neodymium-doped ion region 11, the second sector-shaped erbium-doped ion region 12, the third sector-shaped ytterbium-doped ion region 13, the fourth sector-shaped thorium-doped ion region 14, the fifth sector-shaped praseodymium ion region 15, and the sixth sector-shaped holmium-doped ion region Zone 16, the seventh sector-shaped samarium-doped ion zone 17, the eighth sector-shaped neodymium-ytterbium co-doped ion zone 18, and the ninth sector-shaped erbium-ytterbium co-doped ion zone 19 have the same optical refractive index, radius and radian, forming a complete circular fiber core ;Circular core radius is 20 microns;

Thirty-two fan-shaped fiber cores with the same radius and the same radian are evenly distributed around the circular fiber core in the inner cladding 3; the first fan-shaped fiber core 21, the second fan-shaped fiber core 22, ..., the thirty-second fan-shaped fiber core The radius of the core 232 is 200 microns, and the radian is π/16. The rare earth ion doped in the first fan-shaped fiber core 21, the rare earth ion doped in the second fan-shaped fiber core 22, ..., the 32nd fan-shaped fiber core 232 doped with rare earth The ions are neodymium ions, holmium ions, erbium ions, ytterbium ions, erbium-ytterbium co-doped ions, neodymium-ytterbium co-doped ions, samarium ions, thorium ions, praseodymium ions, erbium ions, ytterbium ions, erbium-ytterbium co-doped ions, ytterbium ions , Erbium-ytterbium co-doped ions, thorium ions, praseodymium ions, erbium-ytterbium co-doped ions, neodymium-ytterbium co-doped ions, erbium-ytterbium co-doped ions, neodymium-ytterbium co-doped ions, samarium ions, thorium ions, praseodymium ions, erbium ions, ytterbium Ions, erbium-ytterbium co-doped ions, ytterbium ions, erbium-ytterbium co-doped ions, thorium ions, praseodymium ions, erbium-ytterbium co-doped ions, neodymium-ytterbium co-doped ions;

The distance between the apex of the first fan-shaped core 21, the second fan-shaped core 22, ..., the thirty-second fan-shaped core 232 and the outer circle of the circular fiber core is equal, and the distance is 20 microns;

The optical refractive index of the circular fiber core, the first fan-shaped fiber core 21, the second fan-shaped fiber core 22, ..., the thirty-second fan-shaped fiber core 232 is equal, and the optical refractive index of the first fan-shaped fiber core 21 is greater than that of the inner cladding 3 The optical refractive index of the inner cladding layer 3 is greater than that of the outer cladding layer 4 .

Nine sector-shaped rare earth ion-doped regions (11, 12, ..., 19) and thirty-two sector-shaped cores (21, 22, ..., 232) circular core multi-sector area peripheral multi-sector core fiber The preparation method comprises the following steps:

Step 1 Fabrication of a circular core thin rod containing an annular cladding region

Choose nine neodymium-doped optical fiber preforms, erbium-doped optical fiber preforms, ytterbium-doped optical fiber preforms, thorium-doped optical fiber preforms, praseodymium-doped optical fiber preforms, and holmium-doped optical fiber preforms with the same core radius and optical refractive index. Ion optical fiber preform, samarium-doped ion optical fiber preform, neodymium-ytterbium co-doped ion optical fiber preform, erbium-ytterbium co-doped ion optical fiber preform;

Part of the cladding of the nine optical fiber prefabricated rods is removed by grinding, so that the thickness of the remaining cladding is equal;

The nine optical fiber prefabricated rods with part of the cladding removed are drawn into thin rods with the same core radius and thickness as the cladding thickness, the core radius is 20mm, and the cladding thickness is 20mm;

Using the method of laser cutting, the above nine optical fiber preform rods are processed into nine fan-shaped thin rods with the same radius and the same radian, and the radian of each fan-shaped thin rod is 2π/9; the nine fan-shaped thin rods form a complete circle , constituting a circular core thin rod with an annular cladding region.

Step 2 Make fan-shaped fiber core rods

Choose neodymium-doped optical fiber preforms with the same core radius and optical refractive index, holmium-doped optical fiber preforms, erbium-doped optical fiber preforms, ytterbium-doped optical fiber preforms, erbium-ytterbium co-doped ion optical fiber preforms, neodymium-ytterbium Co-doped ion optical fiber preform, samarium-doped optical fiber preform, thorium-doped optical fiber preform, praseodymium-doped optical fiber preform, erbium-doped optical fiber preform, ytterbium-doped optical fiber preform, erbium-ytterbium co-doped ion optical fiber preform , Ytterbium Ion Optical Fiber Preform, Erbium Ytterbium Codoped Ion Optical Fiber Preform, Thorium Doped Ion Optical Fiber Preform, Praseodymium Ion Optical Fiber Preform, Erbium Ytterbium Codoped Ion Optical Fiber Preform, NdYtterbium Codoped Ion Optical Fiber Preform, Erbium Ytterbium Co-doped optical fiber preform, Nd-Yb co-doped optical fiber preform, samarium-doped optical fiber preform, thorium-doped optical fiber preform, praseodymium-doped optical fiber preform, erbium-doped optical fiber preform, ytterbium-ion optical fiber preform, Erbium-ytterbium co-doped ion optical fiber preform, ytterbium-doped ion optical fiber preform, erbium-ytterbium-doped ion optical fiber preform, thorium-doped ion optical fiber preform, praseodymium-doped optical fiber preform, erbium-ytterbium-doped ion optical fiber preform, neodymium ytterbium Co-doped ion optical fiber preform, where the optical refractive index of the optical fiber preform core layer is equal to the optical refractive index of the optical fiber preform core layer adopted in step one;

The cladding of thirty-two optical fiber prefabricated rods was removed by hydrofluoric acid etching, leaving only the core layer;

Draw the above thirty-two optical fiber preforms into thin rods with the same radius, the radius is 200mm;

Then use the method of laser cutting to process the above thirty-two optical fiber preforms into thirty-two fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is π/16;

Step 3: Make a circular core multi-sector peripheral multi-sector core fiber

The circular fiber core thin rods and thirty-two fan-shaped fiber core thin rods of the annular cladding region that have completed steps one and two are organized, put on a quartz tube, and the optical refractive index is lower than the fan-shaped thin rods but lower than the fan-shaped thin rods at the gap. The quartz tube is filled with thin quartz rods with high optical refractive index; it is drawn into a circular core multi-sector peripheral multi-sector core fiber.

Embodiment five

N sector-shaped rare-earth ion-doped regions (11, 12, ..., 1N) and M sector-shaped cores (21, 22, ..., 2M) circular-core multi-sector-shaped peripheral multi-sector core fiber, the optical fiber includes Fiber core, inner cladding and outer cladding;

The optical refractive index, radius and radian of the first to Nth fan-shaped rare earth ion-doped regions are all equal, forming a complete circular fiber core; the radius of the circular fiber core is 2 to 20 microns;

Integer of 3≤N≤9;

The first to Mth fan-shaped cores with the same radius and the same radian are evenly distributed around the circular core in the inner cladding;

Integer of N≤M≤32;

The radius of the first fan-shaped fiber core, the second fan-shaped fiber core, ..., the M-th fan-shaped fiber core is 20-200 microns, and the radian is α, π/2M≤α≤2π/M;

The distances between the first fan-shaped core, the second fan-shaped core, ..., the Mth fan-shaped core and the outer circle of the circular fiber core are equal, and the distances are all 2 to 20 microns;

The optical refractive index of the circular core and the first to Mth fan-shaped cores are equal, and the optical refractive index is greater than that of the inner cladding, and the optical refractive index of the inner cladding is greater than that of the outer cladding.

The types of doped rare earth ions in the first to Nth fan-shaped rare earth ion-doped regions are not all the same; the types of doped rare earth ions include neodymium ions, erbium ions, ytterbium ions, thorium ions, praseodymium ions, holmium ions, samarium ions, neodymium ytterbium co-doped ions, Erbium and ytterbium co-doped ions;

The rare earth ion types of the first to M fan-shaped cores are not all the same, and the rare earth ion types contained in the first to M fan-shaped cores are different from the rare earth ion types contained in the first to N fan-shaped rare earth ion regions. Sets are equal.

A method for making a multi-sector core optical fiber at the periphery of a circular core multi-sector area comprises the following steps:

A method for making a multi-sector core optical fiber at the periphery of a circular core multi-sector area comprises the following steps:

Step 1 Fabrication of a circular core thin rod containing an annular cladding region

Select N rare earth ion-doped optical fiber preforms with the same core radius and the same optical refractive index; an integer of 3≤N≤9;

removing part of the cladding of the N optical fiber prefabricated rods, so that the thickness of the remaining cladding is equal;

Drawing N optical fiber preform rods from which part of the cladding has been removed into thin rods with the same core radius and cladding thickness;

Process the above N optical fiber preform rods into N fan-shaped thin rods with the same radius and same radian, and the radian of each fan-shaped thin rod is 2π/N; N fan-shaped thin rods form a complete circle, forming a ring-shaped cladding Circular core thin rods in the area;

Step 2 Make fan-shaped fiber core rods

Select M root doped rare earth ion optical fiber preforms whose core radius is equal to the optical refractive index; N≤M≤32 integers, the optical refractive index of the optical fiber preform core here is the same as the optical fiber preform core adopted in step one The optical indices of refraction of the layers are equal;

The cladding of the M optical fiber prefabricated rods is removed by hydrofluoric acid etching, leaving only the core layer;

drawing the above M optical fiber preforms into thin rods with equal radii;

Then process the above M optical fiber preform rods into M fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is α, π/2M≤α≤2π/M;

Step 3: Make a circular core multi-sector peripheral multi-sector core fiber

The circular fiber core thin rod containing the annular cladding region and M fan-shaped fiber core thin rods that have completed steps 1 and 2 are organized, put on a quartz tube, and the optical refractive index in the gap is lower than that of the fan-shaped thin rod but higher than that of quartz The tube is filled with thin quartz rods with high optical refractive index; it is drawn into a circular core multi-sector peripheral multi-sector core fiber.

Claims (3)

1. A circular core multi-sector peripheral multi-sector core fiber, the fiber comprises a core, an inner cladding (3) and an outer cladding (4); it is characterized in that: The optical refractive index, radius and radian of the first to Nth fan-shaped rare earth ion-doped regions (11, 12, ..., 1N) are all equal, forming a complete circular core; the radius of the circular core is 2 ~20 microns; Integer of 3≤N≤9; The first to Mth fan-shaped cores (21, 22, ..., 2M) of the same radius and the same radian are evenly distributed around the circular core in the inner cladding (3); Integer of N≤M≤32; The radius of the first fan-shaped fiber core (21), the second fan-shaped fiber core (22), ..., the Mth fan-shaped fiber core (2M) is 20-200 microns, and the radian is α, π/2M≤α≤ 2π/M; The distance between the apex of the first fan-shaped fiber core (21), the second fan-shaped fiber core (22), ..., the Mth fan-shaped fiber core (2M) and the outer circle of the circular fiber core is equal, and the distances are 2 to 20 Micron; The optical refractive index of the circular core, the first to the Mth fan-shaped core (21, 22, ..., 2M) is equal, and its optical refractive index is greater than that of the inner cladding (3), and the inner cladding (3) has an optical refractive index greater than that of the outer cladding (4). 2. The circular core multi-sector peripheral multi-sector core fiber according to claim 1, characterized in that: The types of doped rare earth ions in the first to N sector-shaped rare earth ion doped regions (11, 12, ..., 1N) are not all the same; the doped rare earth ion types include neodymium ions, erbium ions, ytterbium ions, thorium ions, and praseodymium ions. ions, holmium ions, samarium ions, neodymium ytterbium co-doped ions or erbium ytterbium co-doped ions; The types of doped rare earth ions in the first to the Mth fan-shaped cores (21, 22, ..., 2M) are not all the same, and the first to the Mth fan-shaped cores (21, 22, ..., The set of rare earth ion types in 2M) is equal to the set of rare earth ion types in the first to Nth fan-shaped rare earth ion doping regions (11, 12, . . . , 1N). 3. The method for making the multi-sector core optical fiber at the periphery of the circular core multi-sector area comprises the following steps: Step 1 Fabrication of a circular core thin rod containing an annular cladding region Selecting N rare earth ion-doped optical fiber preforms with the same core layer radius and the same optical refractive index; an integer of 3≤N≤9; removing part of the cladding of the N optical fiber prefabricated rods, so that the thickness of the remaining cladding is equal; Drawing N optical fiber preform rods from which part of the cladding has been removed into thin rods with the core radius equal to the cladding thickness; Process the above N optical fiber preform rods into N fan-shaped thin rods with the same radius and same radian, and the radian of each fan-shaped thin rod is 2π/N; N fan-shaped thin rods form a complete circle, forming a ring-shaped cladding Circular core thin rods in the area; Step 2 Make fan-shaped fiber core rods Select M rare earth ion-doped optical fiber preforms with the same core radius and optical refractive index; the integer of N≤M≤32, the optical refractive index of the selected M optical fiber preform cores is the same as that of the N optical fibers used in step one The optical refractive index of the preform core layer is equal; Remove the cladding of the M optical fiber prefabricated rods, leaving only the core layer; drawing the above M optical fiber preforms into thin rods with equal radii; Then process the above M optical fiber preform rods into M fan-shaped thin rods with the same radius and radian, and the radian of each fan-shaped thin rod is α, π/2M≤α≤2π/M; Step 3: Make a circular core multi-sector peripheral multi-sector core fiber The circular fiber core thin rod containing the annular cladding area and the M fan-shaped fiber core thin rods of step two are organized to complete the step one, put on a quartz tube, and the optical refractive index in the gap is lower than that of the fan-shaped thin rod, but lower than that of the fan-shaped thin rod. The quartz tube is filled with thin quartz rods with high optical refractive index; it is drawn into a circular core multi-sector peripheral multi-sector core fiber.

Images