Erbium-ytterbium co-doped single-mode optical fiber

Abstract

The erbium-ytterbium co-doped single-mode optical fiber comprises a fiber core, an inner cladding and an outer cladding which are sequentially arranged from inside to outside in the radial direction of the optical fiber. The fiber core is made of erbium-ytterbium co-doped quartz glass, and the inner cladding is made of germanium-doped quartz glass; the refractive index of the fiber core is greater than that of the inner cladding, and the refractive index of the inner cladding is greater than that of the outer cladding; the erbium ion doping concentration in the fiber core is linearly reduced from inside to outside in the radial direction of the optical fiber, and the ytterbium ion doping concentration is kept unchanged from inside to outside in the radial direction of the optical fiber, so that the refractive index of the fiber core is linearly reduced from inside to outside in the radial direction of the optical fiber. According to the invention, the problem of poor light beam quality caused by multi-mode laser in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the field of optical fiber technology, and in particular to an erbium-ytterbium co-doped single-mode optical fiber. Background Art

[0002] Fiber amplifiers were first introduced to meet the development needs of optical communications. The power of optical signals transmitted in optical communication systems is generally in the order of microwatts (μW) to milliwatts (mW). Usually, the maximum output power of a single-stage erbium-doped fiber amplifier (EDFA) is 23dBm, which meets the application requirements of traditional long-distance optical fiber network transmission. With the further development of optical network technology in recent years, the number of optical fiber users has increased, and the power budget in optical communication systems has been further increased, which has put forward higher requirements on the output power of fiber amplifiers.

[0003] Erbium-ytterbium co-doped fiber is a key component material of erbium-ytterbium co-doped fiber amplifier EYDFA. Compared with traditional erbium-doped fiber, erbium-ytterbium co-doped fiber adopts a double-cladding fiber structure in waveguide structure design. The numerical aperture of the inner cladding can be 0.2-0.24, and the inner cladding diameter is about tens of microns, which can allow high-power pump light to be directly coupled to the inner cladding, effectively improving the power input into the fiber and the coupling efficiency, providing a pump source foundation for increasing the maximum output power of the erbium-ytterbium co-doped fiber amplifier.

[0004] In addition, Er-Ytterbium co-doped fiber utilizes Yb 3+ Ions are relatively strong in the quartz glass matrix. 3+ The wider absorption cross section and Yb 3+ With Er 3+ The energy transfer between ions increases Er 3+ The actual pump absorption effect of ions improves the energy conversion efficiency and achieves higher power output of erbium-ytterbium co-doped fiber amplifiers.

[0005] In actual applications, Er-Yb co-doped fibers with large core diameter and high numerical aperture are prone to multi-mode lasers under high power operation, resulting in mode instability and poor beam quality. 3+ Ions and Er 3+ Ions cause uneven distribution of doped ions in the fiber core. At the same time, the conduction distribution of the pump source in the fiber core is not in a single-mode form, resulting in multiple modes of 1550nm laser amplification, which affects the final output beam quality.

[0006] Therefore, it is necessary to design and study Erbium-Ytterbium co-doped optical fibers with large core diameter and high numerical aperture, solve the problem of Erbium-Ytterbium co-doped optical fibers multimode laser, and lay the foundation for the stable operation of high-power optical fiber amplifiers. Summary of the invention

[0007] The embodiment of the present application provides an erbium-ytterbium co-doped single-mode optical fiber to solve the problem of poor beam quality caused by multi-mode laser in the related art.

[0008] In a first aspect, an erbium-ytterbium co-doped single-mode optical fiber is provided, which comprises a core, an inner cladding and an outer cladding arranged in sequence from the inside to the outside along the radial direction of the optical fiber;

[0009] The fiber core is made of erbium-ytterbium co-doped quartz glass, and the inner cladding is made of germanium-doped quartz glass;

[0010] The refractive index of the core is greater than the refractive index of the inner cladding, and the refractive index of the inner cladding is greater than the refractive index of the outer cladding;

[0011] The erbium ion doping concentration in the fiber core decreases linearly from inside to outside along the radial direction of the optical fiber, and the ytterbium ion doping concentration remains unchanged from inside to outside along the radial direction of the optical fiber, so that the refractive index of the fiber core decreases linearly from inside to outside along the radial direction of the optical fiber.

[0012] In some embodiments, the refractive index n of the core is 1 The maximum value of n 1，max , the minimum value is n 1，min , n 1，max Relative to n 1，min The refractive index difference Δn 1，max，1 The value range is 0.0046%;

[0013] in,

[0014] In some embodiments, the refractive index n of the core is 1 The distribution is as follows:

[0015] n 1 =-kx+n 3 (1+Δn 1,max,2 )(1+Δn 2 )

[0016] Wherein, x is the distance between any point in the core and the center point of the core, k is the refractive index reduction rate, n 3 is the refractive index of the outer cladding, Δn 1，max，2 is the refractive index n of the core 1 The maximum value n 1，max Relative to the refractive index n of the inner cladding 2 The refractive index difference, Δn 2 is the refractive index n of the inner cladding 2 Relative to the refractive index n of the outer cladding 3 The refractive index difference.

[0017] In some embodiments, the refractive index n of the core is1 The maximum value of n 1，max , the refractive index of the inner cladding is n 2 , n 1，max Relative to n 2 The refractive index difference Δn 1，max，2 The value range is 0.095% to 0.100%;

[0018] in,

[0019] In some embodiments, the refractive index of the inner cladding is n 2 , the refractive index of the outer cladding is n 3 , n 2 Relative to n 3 The refractive index difference Δn 2 The value range is 1.05% to 1.30%;

[0020] in,

[0021] In some embodiments, the diameter d of the fiber core is 1 The value range is 9.5μm~10.5μm;

[0022] The outer diameter d of the inner cladding 2 The value range is 35μm~40μm;

[0023] The outer diameter d of the outer cladding 3 The value range is 124μm~126μm.

[0024] In some embodiments, an inner coating and an outer coating are sequentially disposed outside the outer cladding.

[0025] In some embodiments, the refractive index n of the inner coating is 4 Less than the refractive index n of the outer coating 5 .

[0026] In some embodiments, the refractive index n of the inner coating is 4 The value range of is 1.365~1.380;

[0027] The refractive index n of the outer coating 5 The value range is 1.481~1.523.

[0028] In some embodiments, the outer diameter d of the inner coating is 4 The value range is 170μm~180μm;

[0029] The outer diameter d of the outer coating 5 The value range is 240μm~250μm.

[0030] The beneficial effects of the technical solution provided by this application include:

[0031] In this application, the Er / Yb co-doped core is designed and Er 3+ The ion doping concentration distribution decreases uniformly from the inside to the outside along the radial direction of the optical fiber. 3+ The ion doping concentration distribution is uniform, that is, it remains unchanged from the inside to the outside along the radial direction of the optical fiber, so that the refractive index of the Er / Yb co-doped core region formed decreases uniformly from the inside to the outside. 3+ Ions are part of the co-dopant, and the fiber pump energy is uniformly absorbed and then passes through the Yb 3+ The ions transfer energy to Er 3+ ions, rather than an evenly distributed Er 3+ Because the distribution of ions is highly consistent with the mode field distribution of the single-mode light spot, they can effectively suppress the generation of non-single-mode lasers, thereby avoiding the problem of deterioration of beam quality caused by multi-mode lasers.

[0032] The present application adds an annular germanium doping layer outside the erbium-ytterbium co-doped core. On the one hand, the refractive index difference between the erbium-ytterbium co-doped core and the annular germanium doping layer is reduced by modifying the waveguide structure, thereby achieving single-mode output characteristics. On the other hand, the absorption coefficient of cladding pump light is improved by increasing the effective area of ​​the erbium-ytterbium co-doped core, thereby achieving the effect of high-power output. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 A schematic diagram of the refractive index of an erbium-ytterbium co-doped single-mode optical fiber provided in an embodiment of the present application;

[0035] Figure 2 A schematic cross-sectional view of an erbium-ytterbium co-doped single-mode optical fiber provided in an embodiment of the present application;

[0036] Figure 3 This is a test diagram of the laser output power of Example 3 provided in this application;

[0037] Figure 4 This is a laser output power test diagram of Comparative Example 2 provided in this application.

[0038] In the figure: 1. Fiber core; 2. Inner cladding; 3. Outer cladding; 4. Inner coating; 5. Outer coating. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0040] See also Figure 1 and Figure 2 As shown, the embodiment of the present application provides an erbium-ytterbium co-doped single-mode optical fiber, which includes a core 1, an inner cladding 2 and an outer cladding 3 arranged in sequence from the inside to the outside along the radial direction of the optical fiber; the core 1 is made of erbium-ytterbium co-doped quartz glass, the inner cladding 2 is made of germanium-doped quartz glass, and the outer cladding 3 can be made of pure quartz glass; the refractive index of the core 1 is n 1 Greater than the refractive index n of the inner cladding 2 2 , the refractive index n of the inner cladding 2 2 Greater than the refractive index n of the outer cladding 3 3 The erbium ion doping concentration in the core 1 decreases linearly from the inside to the outside along the radial direction of the optical fiber, and the ytterbium ion doping concentration remains unchanged from the inside to the outside along the radial direction of the optical fiber, so that the refractive index of the core 1 decreases linearly from the inside to the outside along the radial direction of the optical fiber.

[0041] In this application, the Er / Yb co-doped core is designed and Er 3+ The ion doping concentration distribution decreases uniformly from the inside to the outside along the radial direction of the optical fiber. 3+ The ion doping concentration distribution is uniform, that is, it remains unchanged from the inside to the outside along the radial direction of the optical fiber, so that the refractive index of the Er / Yb co-doped core region formed decreases uniformly from the inside to the outside. 3+ Ions are part of the co-dopant, and the fiber pump energy is uniformly absorbed and then passes through the Yb 3+ The ions transfer energy to Er 3+ ions, rather than an evenly distributed Er 3+ Because the distribution of ions is highly consistent with the mode field distribution of the single-mode light spot, they can effectively suppress the generation of non-single-mode lasers, thereby avoiding the problem of deterioration of beam quality caused by multi-mode lasers.

[0042] The present application adds an annular germanium doped layer outside the erbium-ytterbium co-doped core. On the one hand, the waveguide structure is modified to reduce the refractive index difference between the erbium-ytterbium co-doped core and the annular germanium doped layer, thereby achieving single-mode output characteristics. On the other hand, due to the addition of the germanium-doped inner cladding, the proportion of the overall area of ​​the core 1 and the inner cladding 2 in the entire optical fiber end face area is increased. By increasing the effective area of ​​the erbium-ytterbium co-doped core, the absorption coefficient of the outer cladding pump light is improved, thereby achieving the effect of high-power output.

[0043] Preferably, the refractive index n of the core 1 is 1 The maximum value of n 1，max , the minimum value is n 1，min , n 1，max Relative to n 1，min The refractive index difference Δn 1，max，1 The value range is greater than 0 and less than 0.0055%, for example, preferably 0.0046%; 3+ :Yb 3+ The best ratio of ion concentration is usually 1:10. The linear distribution of erbium ions should not be too high, otherwise the absorption coefficient will be too low and the conversion efficiency will decrease. After system testing, the decrease ratio is controlled within 15%.

[0044] in,

[0045] Preferably, the refractive index n of the core 1 is 1 The distribution is as follows:

[0046] n 1 =-kx+n 3 (1+Δn 1,max,2 )(1+Δn 2 )

[0047] Wherein, x is the distance between any point in the core 1 and the center point of the core 1, k is the refractive index reduction rate, which is used to adjust the speed at which the core refractive index gradually decreases, and the value of k is greater than 0 and less than 0.00008, preferably 0.000067, and n 3 is the refractive index of the outer cladding 3, Δn 1，max，2 is the refractive index n of the core 1 1 The maximum value n 1，max Relative to the refractive index n of the inner cladding 2 2 The refractive index difference, Δn 2 is the refractive index n of the inner cladding 2 2 Relative to the refractive index n of the outer cladding 3 3 The refractive index difference.

[0048] Preferably, the refractive index n of the core 1 is 1The maximum value of n 1，max The refractive index of the inner cladding 2 is n 2 , n 1，max Relative to n 2 The refractive index difference Δn 1，max，2 The value range is 0.095% to 0.100%; the refractive index difference between the core and the inner cladding is within this range. When the core is 10um, the cutoff wavelength of the core is less than 1550nm to avoid the generation of high-order modes.

[0049] in,

[0050] Preferably, the refractive index of the inner cladding 2 is n 2 The refractive index of the outer cladding 3 is n 3 , n 2 Relative to n 3 The refractive index difference Δn 2 The value range is 1.05% to 1.30%;

[0051] in,

[0052] It can be understood that the waveguide structure of the inner cladding 2 is a flat step-type, and its refractive index remains constant from the inside to the outside along the radial direction of the optical fiber.

[0053] Preferably, the diameter d of the fiber core 1 is 1 The value range is 9.5μm~10.5μm;

[0054] The outer diameter d of the inner cladding 2 2 The value range is 35μm~40μm;

[0055] The outer diameter d of the outer cladding 3 3 The value range is 124μm~126μm.

[0056] Preferably, an inner coating 4 and an outer coating 5 are sequentially disposed outside the outer cladding 3 .

[0057] Preferably, the refractive index n of the inner coating 4 is 4 Less than the refractive index n of the outer coating 5 5 The refractive index n of the inner coating 4 is 4 The value range of the outer coating layer 5 is 1.365 to 1.380; 5 The value range is 1.481~1.523.

[0058] The outer diameter d of the inner coating 4 4 The value range of is 170μm to 180μm; the outer diameter d of the outer coating 5 5The value range is 240μm~250μm.

[0059] Example 1

[0060] An erbium-ytterbium co-doped single-mode optical fiber, comprising a core 1, an inner cladding 2, an outer cladding 3, an inner coating 4 and an outer coating 5 arranged in sequence from the inside to the outside along the radial direction of the optical fiber; the core 1 is made of erbium-ytterbium co-doped silica glass, the inner cladding 2 is made of germanium-doped silica glass, and the outer cladding 3 can be made of pure silica glass; the refractive index of the core 1 is n 1 Greater than the refractive index n of the inner cladding 2 2 , the refractive index n of the inner cladding 2 2 Greater than the refractive index n of the outer cladding 3 3 The erbium ion doping concentration in the core 1 decreases linearly from the inside to the outside along the radial direction of the optical fiber, and the ytterbium ion doping concentration remains unchanged from the inside to the outside along the radial direction of the optical fiber, so that the refractive index of the core 1 decreases linearly from the inside to the outside along the radial direction of the optical fiber.

[0061] The refractive index n of the core 1 1 The maximum value of n 1，max The refractive index of the inner cladding 2 is n 2 The refractive index of the outer cladding 3 is n 3 .

[0062] In this embodiment, n 2 Relative to n 3 The refractive index difference Δn 2 is 1.08%, n 1，max Relative to n 2 The refractive index difference Δn 1，max，2 The main component of the inner cladding layer 2 is SiO 2 , dopant is GeO 2 , where according to the refractive index difference designed above, GeO 2 The doping concentration is 12 mol%. The main component of the core 1 is SiO 2 , dopants include Er 2 O 3 , Yb 2 O 3 and P 2 O 5 , where according to the refractive index difference designed above, Er 2 O 3 The doping concentration is 0.08 mol%, Yb 2 O 3 The doping concentration is 0.8 mol%, P 2 O 5 The doping concentration is 12.4 mol%.

[0063] The method for preparing the erbium-ytterbium co-doped single-mode optical fiber comprises the following steps:

[0064] S1, mixing gas raw materials and passing them into a quartz glass tube, depositing and sintering at 1950-2050°C to complete the deposition of an annular germanium-doped quartz glass layer; the raw materials include SiC l 4 、GeCl 4 , O 2 And He. Among them, SiC l 4 The carrier gas O 2 The flow rate is 200sccm, GeCl 4 The carrier gas O 2 The flow rate is 220 sccm. As a further improvement, additional O is introduced into step S1. 2 The flow rate is 2000sccm, and the additional He flow rate is 500sccm.

[0065] S2, on the basis of step S1, continue to mix the gas raw materials and pass them into the quartz glass tube, deposit a single loose layer of the erbium and ytterbium co-doped core region at 1400-1600° C., and deposit 6 times; the raw materials include SiC l 4 、POC 3 , Erbium chelate, Ytterbium chelate, O 2 And He. Among them, SiC l 4 The carrier gas O 2 The flow rate is 100sccm, POC l 3 The carrier gas O 2 The flow rate is 500 sccm, the carrier gas He flow rate of the erbium ion chelate is increased by 2 sccm per pass from 70 sccm to 80 sccm according to the 6 deposition layers, and the carrier gas He flow rate of the ytterbium ion chelate is 230 sccm. As a further improvement, additional O 2 The flow rate is 1500sccm, and the additional He flow rate is 300sccm.

[0066] S3, after the deposition of the single loose layer of the erbium-ytterbium co-doped core region, the heating source returns to the process starting point, and the gas raw material mixture is introduced into the quartz glass tube, wherein the raw material comprises POC l 3 and O 2 The secondary deposition of Er-Yb co-doped core single-layer loose layer and glass sintering were carried out at 1850-1950℃. 3 The carrier gas O 2 The flow rate is 500 sccm. As a further improvement, additional O is introduced in step S3. 2 The flow rate is 1000 sccm.

[0067] S4, based on step S3, the quartz glass tube is melted and shrunk at 2100-2200°C to obtain a core rod. A sleeve is selected to put the core rod into the sleeve for melting and shrinking to obtain a preform, and the preform is drawn at a certain temperature to obtain an erbium-ytterbium co-doped single-mode optical fiber.

[0068] Example 2

[0069] An erbium-ytterbium co-doped single-mode optical fiber, which is different from Example 1 in that:

[0070] Δn 2 is 1.18%, Δn 1，max，2 0.096%,GeO 2 The doping concentration is 13 mol%, P 2 O 5 The doping concentration is 13.9 mol%.

[0071] In step S1, GeCl 4 The carrier gas O 2 The flow rate is 260 sccm.

[0072] In step S2, POC 1 3 The carrier gas O 2 The flow rate is 600 sccm.

[0073] In step S3, POC 1 3 The carrier gas O 2 The flow rate is 600 sccm.

[0074] Example 3

[0075] An erbium-ytterbium co-doped single-mode optical fiber, which is different from Example 1 in that:

[0076] Δn 2 1.26%, GeO 2 The doping concentration is 14 mol%, P 2 O 5 The doping concentration is 15.3 mol%.

[0077] In step S1, GeCl 4 The carrier gas O 2 The flow rate is 30 sccm.

[0078] In step S2, POC 1 3 The carrier gas O 2 The flow rate is 700 sccm.

[0079] In step S3, POC 1 3 The carrier gas O 2 The flow rate is 700 sccm.

[0080] Comparative Example 1

[0081] The difference between Comparative Example 1 and Example 1 is that:

[0082] Er 3+ The ion doping distribution is uniformly distributed from the outside to the inside along the radial direction of the optical fiber, so that the refractive index of the core 1 is n 1，max .

[0083] In step S2, the flow rate of He, a carrier gas, into the erbium ion chelate is 80 sccm.

[0084] Comparative Example 2

[0085] The difference between Comparative Example 2 and Comparative Example 1 is that:

[0086] Δn 2 1.26%, GeO 2 The doping concentration is 14 mol%, P 2 O 5 The doping concentration is 15.3 mol%.

[0087] In step S1, GeCl 4 The carrier gas O 2 The flow rate is 30 sccm.

[0088] In step S2, POC 1 3 The carrier gas O 2 The flow rate is 700 sccm.

[0089] In step S3, POC 1 3 The carrier gas O 2 The flow rate is 700 sccm.

[0090] The parameters of the erbium-ytterbium co-doped single-mode optical fibers in Examples 1 to 3 and Comparative Examples 1 to 2 are shown in Table 1 below:

[0091] Table 1

[0092]

[0093]

[0094] The erbium-ytterbium co-doped single-mode optical fibers in Examples 1 to 3 and Comparative Examples 1 to 2 were tested, and the performance tests included the following contents:

[0095] The above-drawn Er-Yb co-doped single-mode optical fiber was tested for jitter value and conversion efficiency according to the standard "GB / T 15175-2012 Solid-state laser main parameter measurement method" 5.10 output instability and 5.13 electro-optical conversion efficiency test method, and connected to the laser test optical path for testing, see Figure 3 and Figure 4 As shown, compared with Comparative Example 2, Example 3 which optimizes the erbium ion doping distribution effectively suppresses the generation of non-single-mode laser during laser operation, and the output power is more stable.

[0096] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0097] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0098] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. An erbium-ytterbium co-doped single-mode optical fiber, characterized in that: It comprises a fiber core (1), an inner cladding (2) and an outer cladding (3) which are arranged in sequence from the inside to the outside along the radial direction of the optical fiber; The fiber core (1) is made of erbium-ytterbium co-doped quartz glass, and the inner cladding (2) is made of germanium-doped quartz glass; The refractive index of the core (1) is greater than the refractive index of the inner cladding (2), and the refractive index of the inner cladding (2) is greater than the refractive index of the outer cladding (3); The erbium ion doping concentration in the fiber core (1) decreases linearly from the inside to the outside along the radial direction of the optical fiber, and the ytterbium ion doping concentration remains unchanged from the inside to the outside along the radial direction of the optical fiber, so that the refractive index of the fiber core (1) decreases linearly from the inside to the outside along the radial direction of the optical fiber.

2. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 1, characterized in that: The maximum value of the refractive index n1 of the core (1) is n 1，max , the minimum value is n 1，min , n 1，max Relative to n 1，min The refractive index difference Δn 1，max，1 The value range is 0.0046%; in, 3. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 1, characterized in that: The refractive index n1 of the core (1) is distributed as follows: n1=-kx+n3(1+Δn 1,max,2 )(1+Δn2) Wherein, x is the distance between any point in the core (1) and the center point of the core (1), k is the refractive index reduction rate, n3 is the refractive index of the outer cladding (3), Δn 1，max，2 is the maximum value n of the refractive index n1 of the fiber core (1) 1，max The refractive index difference relative to the refractive index n2 of the inner cladding (2), Δn2 is the refractive index difference between the refractive index n2 of the inner cladding (2) and the refractive index n3 of the outer cladding (3).

4. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 1, characterized in that: The maximum value of the refractive index n1 of the core (1) is n 1，max The refractive index of the inner cladding (2) is n2, n 1，max Refractive index difference Δn relative to n2 1，max，2 The value range is 0.095% to 0.100%; in, 5. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 1, characterized in that: The refractive index of the inner cladding (2) is n2, the refractive index of the outer cladding (3) is n3, and the refractive index difference Δn2 of n2 relative to n3 ranges from 1.05% to 1.30%; in, 6. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 1, characterized in that: The diameter d1 of the fiber core (1) has a value range of 9.5 μm to 10.5 μm; The outer diameter d2 of the inner cladding (2) has a value range of 35 μm to 40 μm; The value range of the outer diameter d3 of the outer cladding layer (3) is 124 μm to 126 μm.

7. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 1, characterized in that: An inner coating (4) and an outer coating (5) are sequentially arranged outside the outer cladding (3).

8. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 7, characterized in that: The refractive index n4 of the inner coating (4) is smaller than the refractive index n5 of the outer coating (5).

9. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 8, characterized in that: The refractive index n4 of the inner coating (4) ranges from 1.365 to 1.380; The refractive index n5 of the outer coating (5) ranges from 1.481 to 1.

523.

10. The Erbium-Ytterbium co-doped single-mode optical fiber according to claim 7, characterized in that: The outer diameter d4 of the inner coating (4) has a value range of 170 μm to 180 μm; The value range of the outer diameter d5 of the outer coating layer (5) is 240 μm to 250 μm.

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