CN101694534A - Single-core multiple rare-earth-doped ion region double-clad optical fiber and manufacturing method thereof - Google Patents

Abstract

The invention relates to a single-core multi-rare-earth ion-doped double-clad optical fiber and a manufacturing method thereof, which belong to the field of high-power broadband optical fiber amplifiers, lasers, and special optical fibers, and simultaneously amplify signals in O, E, S, C, L, and U/XL bands. The single-core structure of the double-clad optical fiber is easy to be directly fused with common optical fibers, and its core layer includes N independent and non-identical doped rare earth ion regions, 2≤N≤20. Its production steps: Step 1, drawing 2≤N≤20 rare earth ion-doped double-clad optical fiber prefabricated rods into thin rods with the same core diameter, and removing the outer cladding of these thin rods; Step 2, Remove the N thin rods of the outer cladding for processing, so that the core layer of the thin rods becomes fan-shaped; step 3, organize the processed N thin rods, put them on a quartz tube, and draw them into a single-core multi-doped rare earth ion zone double clad fiber. The use of optical fiber prefabricated rods to produce single-core multi-doped optical fibers simplifies the manufacturing process, has a compact structure, and is less affected by the environment.

Description

Single-core multi-doped rare earth ion region double-clad optical fiber and its manufacturing method

technical field

The invention relates to a single-core multi-rare-earth ion-doped double-clad 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 the samarium-doped optical fiber is 651nm, and the gain bandwidth and properties of the rare-earth ions doped with different glass substrates are also different. 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. NewYork: 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.

Contents of the invention

In order to overcome that the existing traditional double-clad optical fiber can only amplify a very narrow wavelength range, the invention provides a single-core multi-doped rare earth ion region double-clad optical fiber and a manufacturing method thereof.

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

Single-core multi-doped rare earth ion region double-clad optical fiber, the core layer includes N independent rare earth ion doped regions, an integer of 2≤N≤20, wherein at least two of the N rare earth ion doped regions have rare earth ion doped regions Different types.

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 ytterbium co-doped ions.

A method for manufacturing a single-core multi-doped rare earth ion region double-clad optical fiber, comprising the following steps:

Step 1, drawing N preformed rods of rare earth ion-doped double-clad optical fibers into thin rods with the same core diameter, and removing the outer cladding of these thin rods, an integer of 2≤N≤20;

Step 2, processing the N thin rods from which the outer cladding has been removed, so that the core layer of the thin rods becomes fan-shaped;

Step 3: Organize the processed N thin rods, cover them with quartz tubes, and draw them into single-core multi-doped rare earth ion region double-clad optical fibers.

For the single-core optical fiber manufactured according to the above steps, there are at least two double-clad optical fiber prefabricated rods with different rare earth ion types.

The types of rare earth ions doped in the preform of the double-clad optical fiber in step 1 include neodymium ions, erbium ions, ytterbium ions, thorium ions, praseodymium ions, holmium ions, samarium ions, neodymium-ytterbium co-doped ions, and erbium-ytterbium co-doped ions.

The beneficial effects of the present invention are specifically as follows: the single-core multi-doped rare earth ion region double-clad optical fiber can amplify signals in a wide range of wavelengths from 400nm to 2900nm including O, E, S, C, L, and U/XL bands. Compared with the traditional amplified multi-band signal, it is necessary to configure the corresponding rare-earth ion-doped double-clad fiber for each band and then combine the signals. Obviously, the use of multi-rare-earth ion-doped multi-core double-clad fiber can significantly reduce the connection loss. The structure is more compact. The core layer of the double-clad fiber is divided into different fan-shaped areas according to the different doped rare earth ions. On the one hand, each doped rare earth ion has a greater gain due to the shared inner cladding. On the other hand, due to the different output areas of the amplified optical signal, It provides convenience for related signal processing. The single-core structure makes this kind of fiber easy to be directly fused with ordinary fiber. Since a plurality of double-clad optical fiber preforms doped with different rare earth ions are used to produce a single-core multi-rare earth ion-doped optical fiber, the manufacturing process is simplified, the structure is compact, and the environment is less affected.

Description of drawings

Figure 1 is a cross-sectional view of a single-core double-clad fiber with four rare earth ion-doped regions.

Fig. 2 is a cross-sectional view of a single-core double-clad fiber with two rare earth ion-doped regions.

Fig. 3 is a cross-sectional view of a single-core double-clad fiber with ten rare earth ion-doped regions.

Fig. 4 is a cross-sectional view of a single-core double-clad fiber with twenty rare-earth ion-doped regions.

FIG. 5 is a cross-sectional view of the core layer doped with rare earth ions in FIG. 4 .

Detailed ways

The present invention does not relate to the manufacture of rare earth ion core double-clad 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

Single-core multi-doped rare earth ion region double-clad fiber, the core layer includes independent neodymium-doped ion region, holmium-doped ion region, erbium-doped ion region and ytterbium-doped ion region, see Figure 1.

The manufacturing method of the above-mentioned single-core four-doped rare earth ion region double-clad optical fiber is described in detail as follows:

Step 1, making four rare earth ion-doped double-clad optical fiber preforms, the four optical fiber preforms doped with rare earth ions are neodymium ions, holmium ions, erbium ions and ytterbium ions respectively, and the inner cladding shapes of the four optical fiber preforms are all round Rectangular shape; the four different rare earth ion-doped double-clad optical fiber prefabricated rods are drawn into thin rods with a rounded rectangular (200×160 mm) inner cladding with a core layer diameter of 10 mm.

Step 2, using hydrofluoric acid to corrode the outer cladding layers of the four thin rods whose core layers are all 10 mm in diameter, leaving two layers of the inner cladding layer and the core layer.

In step 3, laser cutting is performed on the four thin rods with the outer cladding removed, so that the core layer of each thin rod is fan-shaped with a radian of π/2.

Step 4, organize the four thin rods processed in Step 3, and put on a quartz tube with an inner diameter of 200 mm.

In step five, the thin rod completed in step four is drawn into a single-core double-clad optical fiber with four rare earth ion-doped regions with a core layer diameter of 1 μm. The shape of the inner cladding layer 2 is a rounded rectangle, the shape of the outer cladding layer 1 is a circle, and the inner area of the core layer is divided into four regions: neodymium-doped ion region 3, holmium-doped ion region 4, erbium-doped ion region 5 and ytterbium-doped ion region Area 6, as shown in Figure 1.

Embodiment two

Single-core multi-doped rare earth ion region double-clad fiber, its core layer includes independent holmium-doped ion region, ytterbium-erbium ion-doped region, see Figure 2.

The above-mentioned method for manufacturing a single-core double-clad optical fiber with two rare earth ion-doped regions is described in detail as follows:

Step 1, making two rare-earth ion-doped double-clad optical fiber preforms, the two optical fiber preforms doping rare-earth ions are respectively holmium ions and erbium-ytterbium co-doped ions, and the inner claddings of the two preforms are both circular in shape; These two double-clad optical fiber prefabricated rods doped with different rare earth ions were drawn into a thin rod with a core layer diameter of 5mm and an inner cladding diameter of 150mm.

In step 2, the outer cladding of the above two thin rods is removed by laser cutting, leaving two layers of the inner cladding and the core layer.

Step 3, grind the thin rod with the outer cladding removed, so that the thin rod core and inner cladding layer of erbium and ytterbium co-doped are fan-shaped with 2π/3 radians, and the thin rod core layer and inner cladding layer doped with holmium ions are π/ 3 radian sector.

Step 4, organize the two thin rods processed in Step 3, and put on a quartz tube with an inner diameter of 150 mm.

In step five, the rod completed in step four is drawn into a single-core double-clad optical fiber with two rare earth ion-doped regions with a core layer diameter of 8 μm. The shape of the inner cladding layer 2 is circular, and the shape of the outer cladding layer 1 is circular. The core layer is divided into two regions: the co-doped region 7 of erbium and ytterbium ions and the region 8 of doped holmium ions, as shown in FIG. 2 .

Embodiment three

Single-core multi-doped rare earth ion region double-clad fiber, the core layer includes independent neodymium-doped ion region, holmium ion region, erbium ion region, ytterbium ion region, erbium-ytterbium co-doped ion region, neodymium-ytterbium co-doped ion region, erbium Ion region, ytterbium ion region, erbium-ytterbium co-doped ion region, erbium ion region, see Figure 3.

The method for manufacturing the above-mentioned single-core double-clad optical fiber with ten rare earth ion-doped regions is described in detail as follows:

Step 1, making ten rare earth ion-doped double-clad optical fiber preforms, the ten optical fiber preforms doped with rare earth ions are neodymium ions, holmium ions, erbium ions, ytterbium ions, erbium-ytterbium co-doped ions, neodymium-ytterbium co-doped ions, Erbium ions, ytterbium ions, erbium-ytterbium co-doped ions, erbium ions, and the inner cladding shapes of the ten preforms are all regular octagons; these ten rare earth ion-doped double-clad optical fiber preforms are drawn into a core layer with the same diameter A thin rod with a diameter of 1mm and an inner cladding diameter of 40mm;

Step 2, remove the outer cladding of the above ten thin rods by grinding, leaving two layers of the inner cladding and the core layer;

Step 3, carrying out hydrofluoric acid corrosion treatment to the thin rods from which the outer cladding has been removed, so that each thin rod core and inner cladding are fan-shaped with π/5 radians;

Step 4, organize the ten thin rods processed in step 3, and put on a quartz tube with an inner diameter of 40mm;

In step five, the rod completed in step four is drawn into a single-core double-clad optical fiber with ten rare earth ion-doped regions with a core layer diameter of 10 μm. The shape of the inner cladding 2 is an octagonal rectangle, the shape of the outer cladding 1 is circular, and the core layer is divided into ten regions: neodymium ion region 9, holmium ion region 10, erbium ion region 11, 15 and 18, and ytterbium ion region 12 and 16 , erbium and ytterbium co-doped ion regions 13 and 17 , and neodymium and ytterbium co-doped ion regions 14 , as shown in FIG. 3 .

Embodiment four

Single-core multi-doped rare earth ion region double-clad fiber, its core layer includes independent neodymium-doped ion region, holmium-doped ion region, erbium-doped ion region, ytterbium-doped ion region, erbium-ytterbium co-doped ion region, neodymium-ytterbium co-doped ion region region, samarium-doped ion region, thorium-doped ion region, praseodymium-doped ion region, erbium-doped ion region, ytterbium-doped ion region, erbium-ytterbium co-doped ion region, ytterbium-doped ion region, erbium-ytterbium co-doped ion region, thorium-doped ion region , praseodymium-doped ion region, erbium-ytterbium co-doped ion region, neodymium-ytterbium co-doped ion region, neodymium-doped ion region, holmium-doped ion region, see Figure 4 and Figure 5.

The manufacturing method of the above-mentioned single-core twenty-rare-earth ion-doped double-clad optical fiber is described in detail as follows:

Step 1, making twenty rare earth ion-doped double-clad optical fiber preforms, the core layer of twenty optical fiber preforms doped with rare earth ions are neodymium ions, holmium ions, erbium ions, ytterbium ions, erbium-ytterbium co-doped ions, neodymium ytterbium ions 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 ions, neodymium ions, and holmium ions; the shape of the inner cladding of the twenty preforms is circular; the twenty rare earth ion-doped double-clad optical fiber preforms are drawn into a core layer with a diameter of 2mm and an inner cladding diameter of 80mm thin rod;

Step 2, the outer cladding of above-mentioned twenty thin rods is removed by grinding, leaving two layers of inner cladding and core layer;

Step 3, mechanically cutting the thin rods from which the outer cladding has been removed, so that each thin rod core and inner cladding are fan-shaped by π/10 radians;

Step 4, organize twenty thin rods processed in step 3, and put on a quartz tube with an internal diameter of 80mm;

In step five, the rod completed in step four is drawn into a single-core double-clad optical fiber with twenty rare earth ion-doped regions with a core layer diameter of 20 μm. As shown in FIG. 4 , the shape of the inner cladding layer 2 is circular, and the shape of the outer cladding layer 1 is circular. FIG. 5 is an enlarged display of the core layer 100 in FIG. 4. The core layer 100 is divided into twenty regions: neodymium ion regions 19 and 37, holmium ion regions 20 and 38, erbium ion regions 21 and 28, ytterbium ion regions 22, 29 and 31, erbium and ytterbium co-doped ion regions 23, 30, 32 and 35, neodymium and ytterbium co-doped ion regions 24 and 36, samarium ion region 25, thorium ion region 26 and 33, praseodymium ion region 27 and 34,

Embodiment five

Single-core multi-doped rare earth ion region double-clad optical fiber, the core layer includes N independent rare earth ion doped regions, an integer of 2≤N≤20, wherein at least two of the N rare earth ion doped regions have rare earth ion doped regions Different types.

The manufacturing method of the above single-core multi-doped rare earth ion region double-clad optical fiber:

Step 1, making N rare earth ion-doped double-clad optical fiber preforms, N being an integer between 2 and 20, the core layers of N optical fiber preforms doped with rare earth ions are not all the same, and the shape of the inner cladding is any shape, and the rare earth ion doped The double-clad optical fiber preform is drawn into a thin rod with the same core diameter, and the core diameter of the thin rod is 1-10mm;

Step 2, remove the outer cladding of the above twenty thin rods by grinding or laser cutting or mechanical cutting or hydrofluoric acid corrosion, leaving two layers of inner cladding and core layer;

Step 3, grinding or laser cutting or mechanical cutting or hydrofluoric acid corrosion treatment on the thin rod with the outer cladding removed, so that the core layer of the thin rod is fan-shaped;

Step 4, organize the treated thin rods and put them on quartz tubes;

Step 5: Drawing the rod completed in Step 4 into a double-clad optical fiber with a single core and 20 rare earth ion-doped regions with a core layer diameter of 1-20 μm.

Claims (4)

1. single-core multiple rare-earth-doped ion region double-clad optical fiber is characterized by: sandwich layer comprises N independent rare-earth-doped ion region, and the integer of 2≤N≤20 wherein has the rare-earth ion-doped type difference in two districts at least in this N rare-earth-doped ion region.

2. single-core multiple rare-earth-doped ion region double-clad optical fiber according to claim 1 is characterized by: rare-earth ion-doped type comprises that neodymium ion, erbium ion, ytterbium ion, thorium ion, praseodymium ion, holmium ion, samarium ion, neodymium ytterbium mix ion, erbium and ytterbium codoping ion altogether.

3. the method for making of single-core multiple rare-earth-doped ion region double-clad optical fiber is characterized by: may further comprise the steps:

Step 1 is drawn into the thin rod of sandwich layer equal diameters with the prefabricated rods of the rare-earth ion-doped doubly clad optical fiber of N root, and surrounding layers of these thin rods are removed the integer of 2≤N≤20;

Step 2 is handled the thin rod of N root that removes surrounding layer, makes the sandwich layer of thin rod become fan-shaped;

Step 3 is organized the thin rod of N root after handling, and puts quartz ampoule, is drawn into single-core multiple rare-earth-doped ion region double-clad optical fiber.

4. the method for making of single-core multiple rare-earth-doped ion region double-clad optical fiber according to claim 3, it is characterized by: have the rare-earth ion-doped type difference of two prefabricated rods in the prefabricated rods of rare-earth ion-doped doubly clad optical fiber at least, the rare-earth ion-doped type of prefabricated rods comprises that neodymium ion, erbium ion, ytterbium ion, thorium ion, praseodymium ion, holmium ion, samarium ion, neodymium ytterbium mix ion, erbium and ytterbium codoping ion altogether.

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