阅读说明：本技术 芯体具有径向依赖性α分布的宽带多模光纤 (Broadband multimode optical fiber with radially dependent α distribution core ) 是由 X·陈 李明军 于 2018-06-22 设计创作，主要内容包括：一种多模光纤包括芯体区域，其具有二氧化硅和外半径R。光纤的包层包围芯体区域并且包含二氧化硅。芯体区域具有折射率分布，其具有径向依赖性α。径向依赖性α通过α(r)＝f(r)给出。(A multimode optical fiber includes a core region having silica and an outer radius r.a cladding of the optical fiber surrounds the core region and contains silica the core region has a refractive index profile having a radial dependence α the radial dependence α is given by α (r) ═ f (r).)

1. A multimode optical fiber, comprising:

a core region in the optical fiber comprising silica and an outer radius R; and

a cladding surrounding the core region and comprising silica,

wherein the core region has a refractive index profile with a radial dependence α, the radial dependence α being given by α (r) ═ f (r), and in a continuous manner from a larger value α α at the center of the core region₀A smaller α value at the transition to the outer radius, and a difference Δ α between the larger α value and the smaller α value is 0.005 to 0.08.

2. The optical fiber of claim 1, wherein f (r) α₀-Δα(r/R)ⁿThe radial position R in the core region is from 0 to R, and n is between about 1 to about 3.

3. The optical fiber of claim 2, wherein n equals 2.

4. The optical fiber of claim 2, wherein the average modal bandwidth of the fiber at 950nm is at least 2.5 GHz-km.

5. The optical fiber of claim 4, wherein the peak wavelength of the optical fiber is in the range of 870nm to 900 nm.

6. The optical fiber of claim 2, wherein the average modal bandwidth of the fiber at 850nm is at least 4.7 GHz-km.

7. The optical fiber of claim 2, wherein the core is doped with GeO₂And the cladding is doped with fluorine.

8. The optical fiber of claim 2, wherein the relative refractive index of the core is 0.7% to 1.3%.

9. The optical fiber of claim 2, wherein the core has an outer radius R of about 14 μm to about 27 μm.

10. The optical fiber of claim 2, wherein α₀From 2.0 to 2.2 and a Δ α from 0.01 to 0.04.

11. The optical fiber of claim 2, wherein the cladding comprises a depressed region having a relative refractive index that is substantially constant and lower than the relative refractive index of the core region.

12. The optical fiber of claim 11, wherein the cladding further comprises an inner cladding having a relative refractive index between the relative refractive index of the core region and the relative refractive index of the depressed region, and the depressed region is separated from the core region by the inner cladding.

13. A multimode optical fiber, comprising:

a core region in the optical fiber comprising silica and an outer radius R; and

a cladding surrounding the core region and comprising silica,

wherein the core region has a refractive index profile with a radial dependence α, the radial dependence α being in a continuous manner from a larger α value α at the center of the core region₀A smaller α value at the transition to the outer radius, and the difference δ between the larger α value and the smaller α value is 0.005 to 0.08, and α₀Is 1.7 to 2.3.

14. The optical fiber of claim 13, wherein the radial dependency α is determined by α (r) ═ 2.0557+0.0263 · Δ_{1 max}·[1-(r/R)^α0]+ δ gives, the radial position R in the core region is from 0 to R, and Δ_{1 max}A peak refractive index change in the center of the core region where r is 0.

15. The optical fiber of claim 14, wherein the core is doped with GeO₂And the cladding is doped with fluorine.

16. The optical fiber of claim 14, wherein the core has a relative refractive index of 0.7% to 1.3%.

17. The optical fiber of claim 14, wherein the cladding comprises a depressed region having a relative refractive index that is substantially constant and lower than the relative refractive index of the core region.

18. The optical fiber of claim 17, wherein the cladding further comprises an inner cladding having a relative refractive index between the relative refractive index of the core region and the relative refractive index of the depressed region, and the depressed region is separated from the core region by the inner cladding.

19. A multimode optical fiber, comprising:

a core region in the optical fiber comprising silica and an outer radius R; and

a cladding surrounding the core region and comprising silica,

wherein the core region has a refractive index profile having a radial dependence α, the radial dependence α being given by α (r) α₀-Δα(r/R)ⁿWherein α₀Is 1.9 to 2.3, Δ α is 0.005 to 0.08, and the radial position in the core region R is 0 to R, n is between about 1 to about 3.

20. The optical fiber of claim 19, wherein the average modal bandwidth of the fiber at 850nm to 950nm is at least 10% greater than the average modal bandwidth of a comparative fiber at 850nm to 950nm, the comparative fiber comprising a core region having a refractive index profile with a constant α, the constant α being substantially equal to α₀。

21. The optical fiber of claim 20, wherein the core region is doped with GeO₂And the cladding is doped with fluorine.

22. The optical fiber of claim 20, wherein the optical fiber has a modal bandwidth at 950nm that is at least 10% greater than a mode bandwidth at 950nm of a comparative optical fiber comprising a core region having a refractive index profile with a constant α, the constant α being substantially equal to α₀。

23. The optical fiber of claim 20, wherein the cladding comprises a depressed region having a relative refractive index that is substantially constant and lower than the relative refractive index of the core region.

24. The optical fiber of claim 23, wherein the cladding further comprises an inner cladding having a relative refractive index between the relative refractive index of the core region and the relative refractive index of the depressed region, and the depressed region is separated from the core region by the inner cladding.

Background

The present disclosure relates generally to broadband multimode optical fibers, and more particularly to broadband multimode optical fibers (MMF) having a core with a radially dependent α profile.

Optical fibers, including multimode fibers, are envisioned for data centers and fiber optic home networks, among other applications, and have a large window of operation, facilitating data transmission over an increasingly large range of wavelengths. For example, multimode optical fibers (MMF) with graded-index cores are being designed and envisioned to operate in the wavelength range around 850 nm. Recent applications envision that the operating wavelength is not limited to wavelengths around 850 nm. Some recent applications envision operating wavelengths in the range of 840nm to 860 nm. Other recent applications envision operating wavelengths in the range of 840nm to 953 nm. It is envisaged that some of these new optical fiber designs have complex refractive index profiles, typically with two or more dopants having different concentration profiles. To meet the OM4 standard for the modal bandwidth proposed by TIA, the MMF needs to have an Effective Modal Bandwidth (EMB) of 4700MHz-km at 850 nm. Recently, the TIA proposed and standardized a new standard for MMF, which is called OM5 and recorded in TIA-492 AAAE. For an MMF that meets the OM5 standard, the MMF should meet the OM4 EMB requirements at 850nm, while still providing an EMB of 2470MHz-km at 953 nm.

The peak wavelength of the MMF currently being produced is near the upper end of the acceptable range that meets the OM5 standard set forth by the TIA. To comply with the OM4 standard proposed by the TIA, the peak wavelength may fall within a range of approximately between 815nm and 895 nm. To comply with OM5 EMB at 953nm, existing MMFs typically have a peak wavelength of 880nm or higher. However, currently available MMFs conforming to the OM4 standard typically have a Differential Modal Dispersion (DMD) centroid that is flat at its peak wavelength, while at longer wavelengths (e.g., 950nm) the DMD centroid often translates into a forward or right-leaning distribution, which can make it difficult to manufacture MMFs conforming to the OM5 standard at 850nm and 953 nm.

Thus, there is a need for a broadband MMF with a DMD centroid having a backward or left-leaning distribution at the peak wavelength and an increased EMB at wavelengths greater than 850nm (e.g., 950 nm).

Disclosure of Invention

The core region has a refractive index profile having a radial dependency α the radial dependency α is given by α (r) ═ f (r), and is given in a continuous manner from a larger α value α at the center of the core region₀The smaller α value at the transition to the outer radius the difference Δ α between the larger α value and the smaller α value is 0.005 to 0.08.

Another aspect of the present disclosure relates to a multimode optical fiber comprising a core region in the optical fiber, the core region comprising silica and an outer radius R.A cladding of the optical fiber surrounds the core region and comprises silica the core region has a refractive index profile having a radial dependence α, the radial dependence α being in a continuous manner from a larger α value α at a center of the core region₀A smaller α value at the transition to the outer radius the difference delta between the larger α value and the smaller α value is 0.005 to 0.08, and α₀Is 1.7 to 2.3.

Another aspect of the present disclosure relates to a multimode optical fiber comprising a core region in the optical fiber, the core region comprising silica and an outer radius r. a cladding of the optical fiber surrounds the core region and comprises silica the core region has a refractive index profile having a radial dependence α, the radial dependence α being given by α (r) ═ α₀-Δα(r/R)ⁿWherein α₀Is 1.9 to 2.3, Δ α is 0.005 to 0.08, the radial position R in the core region is 0 to R, and n is between about 1 to about 3.

In some embodiments of the foregoing aspects of multimode optical fiber, the radial dependency α may be achieved by α (r) ═ α₀-Δα(r/R)ⁿIn some alternative embodiments of the foregoing aspects of multimode optical fiber, the radial dependence α can be given by α (r) ═ 2.0557+0.0263 · Δ @_{1 max}·[1-(r/R)^α0]+δ。

In an embodiment of the foregoing aspect of the multimode optical fiber, α₀May be in the range of about 1.7 to about 2.3, about 1.7 to about 2.2, about 1.7 to about 2.1, about 1.7 to about 2.0, about 1.7 to about 1.9, about 1.7 to about 1.8, about 1.8 to about 2.3, about 1.8 to about 2.2, about 1.8 to about 2.1, about 1.8 to about 2.0, about 1.8 to about 1.9, about 1.9 to about 2.3, about 1.9 to about 2.2, about 1.9 to about 2.1, about 1.9 to about 2.0, about 2.0 to about 2.3, about 2.0 to about 2.2, about 2.0 to about 2.1, about 2.1 to about 2.3, about 2.1 to about 2.2.2, or about 2.2 to about 2.3.3.3, may have a constant mode index of refraction at least about 0.04 to about 0.08% in the optical fiber at a mode bandwidth of the optical fiber at a constant mode bandwidth of the optical fiber at least about 0.7 to about 2.3, about 3, about 2.3, the mode of the aforementioned mode of the optical fiber at a constant mode of the optical fiber at a bandwidth of the optical fiber at least the optical fiber loss at least the wavelength of the optical loss at the bandwidth of the optical loss at least one of the optical fiber loss, the mode of the optical loss at least about 2.0 to about 0.0.0 to about 2.0 to about 2.3, the mode of the₀. In some embodiments, the average modal bandwidth of the fiber at 850nm is at least 4.7 GHz-km.

In some of the foregoing aspects of the multimode optical fiber, the core region is doped with GeO₂And the cladding is doped with fluorine. In some embodiments, the cladding includes a depressed region having a relative refractive index that is substantially constant and lower than the relative refractive index of the core region and the remainder of the cladding. In other embodiments, the cladding further comprises an inner cladding having a relative refractive index between that of the core region and that of the depressed region, and the depressed region is separated from the core region by the inner cladding.

In some embodiments of the foregoing aspect, n is equal to 2. In other embodiments, the core has a relative refractive index of 0.7% to 1.3%. The core may have an outer radius R of about 14 μm to about 27 μm.

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the various embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide an overview or framework for understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operations of the various embodiments.

Drawings

FIG. 1 schematically illustrates a cross-sectional view of a multimode optical fiber.

FIG. 1A depicts a schematic refractive index profile of the multimode optical fiber shown in FIG. 1.

Fig. 2 is a graph illustrating a bandwidth versus wavelength plot and associated peak profiles for two comparative fibers having a constant α profile.

Fig. 3 is a graph illustrating effective modal bandwidth versus wavelength plots for four exemplary fibers.

FIG. 4 is a graph illustrating α values versus normalized radius for a comparison fiber and a fiber of the present disclosure.

Fig. 5 is a graph illustrating the change in refractive index according to the indicated radius for a comparative optical fiber and the optical fiber of the present disclosure.

Fig. 6 is a graph illustrating a difference in refractive index profiles of a comparative optical fiber and the optical fiber of the present disclosure shown in fig. 5.

Detailed Description

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

As used herein, "root mean square pulse broadening" or "RMS pulse broadening" refers to the degree of pulse broadening at or away from a wavelength corresponding to the bandwidth of a given fiber (e.g., in ns/km) at a given wavelength. In addition, Root Mean Square (RMS) pulse broadening is a result of RMS time delay in multi-film (MMF) fibers. More specifically, the RMS pulse broadening, σ, is given by equations (1) and (2):

σ²＝<τ²>-<τ>²(1)

where τ (m) is the time delay of mode m, L is the fiber length, m₁Is the coefficient of dispersion of the material, n₁Is the refractive index value in the core center of the optical fiber, B is the normalized propagation constant, λ is the wavelength, c is the velocity of light in vacuum, and<>represents an averaging operation (as shown in equation (2A) below). For a set of variables x₁,x₂,...x_NThe average value of x is given by the following equation (2A):

"refractive index profile" is the relationship between the refractive index or relative refractive index and the waveguide fiber radius.

The terms "μm" and "micron" are used interchangeably herein.

"percent relative refractive index" is defined in equation (3) below as:

Δ％＝100×(n_i ²-n_c ²)/2n_i ²(3)

wherein n is_cIs the refractive index of undoped silica, and n_iIs the average refractive index at point i in a particular region of the fiber.

Unless otherwise indicated, the relative refractive indices, as also used herein, are expressed in Δ (and δ), and the values are given in units of "%". The terms Δ,% Δ, Δ%, delta refractive index, refractive index percent, delta refractive index percent, and% are used interchangeably herein. In the case where the refractive index of a region is less than that of undoped silica, the relative refractive index percent is negative and the regionReferred to as having a depressed region or depressed index of refraction. In the case of a refractive index greater than that of undoped silica, the relative refractive index percentage is positive. A "positive dopant" is considered herein to be a dopant that has a tendency to increase the refractive index relative to pure undoped silica. "negative dopant" is considered herein to be a dopant that has a tendency to lower the refractive index relative to pure undoped silica. Examples of the positive dopant include GeO₂、Al₂O₃、P₂O₅、TiO₂Cl and Br. Further, the terms "germanium oxide", "Ge" and "GeO₂"used interchangeably herein and refers to GeO₂. Examples of the negative dopant include F and B. Furthermore, the terms "fluorine" and "F" are used interchangeably to refer to fluorine dopants derived from fluorine dopant precursors, including but not limited to CF₄、SiF₄And C₂F₆。

Also as used herein, the terms "preform," "preform," and "optical fiber preform" are used interchangeably and refer to an article comprising doped or undoped silica that may be used in the manufacture of optical fibers. The term "soot" refers to doped or undoped silica particles having a diameter in the range of about 5nm to about 5 microns. The soot preform may comprise a surface area ≧ 2m²Soot per gram. In some embodiments, the soot preform comprises a surface area ≧ 5m²Soot per gram; in some embodiments, the soot has a surface area ≧ 20m²(ii)/g; in some embodiments, the soot has a surface area of 50m or more²(ii)/g; in some embodiments, the soot has a surface area of 200m or more²(ii)/g; and in some embodiments, the soot has a surface area of 2m or more²Is less than or equal to 50m²(ii) in terms of/g. The soot preform may comprise a bulk density of 0.1g/cm or more²Soot of (a); in some embodiments, the soot has a bulk density of 0.2g/cm or more²(ii) a In some embodiments, the soot has a bulk density of 0.5g/cm or more²(ii) a In some embodiments, the soot has a bulk density of 1g/cm or more²(ii) a And in some embodiments, the soot has a bulk density ≧ 0.2g ≧cm²And is less than or equal to 1g/cm²。

The term "α" or "α -profile" refers to the relative refractive index profile expressed in terms of Δ (r) ("%") where r is the radius, and follows equation (4) as follows:

wherein Δ_{lmax (l)}Is the peak refractive index change in the center of the optical fiber or optical fiber preform (i.e., core delta), and R is the core radius unless otherwise specified, α reported herein is the refractive index profile measured at 850 nm. α -1 corresponds to a triangular relative refractive index profile, α -2 describes a parabolic profile, and α is the refractive index profile reported for optical fiber>12 corresponds to a profile that is close to a step index profile (i.e., "step-like index profile" as used herein.) thus, α ∞ corresponds to a full step index profile.

Wherein α remains constant.

Equations (4) and (5) describe the refractive index of the comparative MMF.the comparative MMF has a constant value at all positions along the diameter of the core region α. changing α results in a change in the wavelength at which the MMF reaches the maximum mode bandwidth.for example, a MMF with a α value of about 2.10 has a maximum mode bandwidth at about 850 nm.the DMD centroid of the MMF is defined as the average delay of the received laser pulse at a particular DMD emission offset.at or near the maximum mode bandwidth of the MMF, the DMD centroid may have a substantially flat distribution however, as the wavelength of the light moves to a longer wavelength than that associated with the maximum mode bandwidth, the distribution of the centroid may become right-tilted or forward.e.g., the centroid may be flat at the maximum mode bandwidth of 850nm, however, as the wavelength increases to 950nm, the DMD centroid becomes skewed and asymmetric.the right-tilt is the resulting shift between the laser pulse and a particular emission offset at the maximum mode bandwidth is sufficient to shift the DMD emission wavelength to meet the required for the transition between the DMD wavelength shift at α and α, the peak wavelength shift of the DMD, which may be greater than the wavelength shift of the DMD at 36900 nm.

According to one aspect of the present disclosure, the α value for MMF includes a radial dependence based on the radial position in the core region of the optical fiber.

α(r)＝f(r) (6)

Where α (r) is the radial distribution of α in the core region, and f (r) indicates that in the core region α varies as a function of radius r in conjunction with equations (5) and (6), the refractive index of the core region may follow the form of equation (7):

although function α (R) has a baseline radial dependence based on a fixed α value, the α values of the MMF of the present disclosure decrease as a function of radial position along the radius of the core region.

In particular, α in the core region varies as a function of radial position such that the value of α decreases as the radial displacement from the center of the core region increases.

Equation (8) depicts the achievement of a "ramp" α distribution over the radius of the core region according to one embodiment radial dependency α has a baseline, i.e., a starting point α at the center of the core region₀α the radial dependency is established at an initial value α₀The difference between comparing MMF to the α distribution of MMF disclosed herein can be clearly seen by using normalized radius R/R, as shown in FIG. 4, the value α of the MMF disclosed herein is greatest at the center of the core area, which is the location associated with the x coordinate of 0.0. the maximum change or Δ α occurs at the outer radius of the core area, which is the location associated with the x coordinate of 1.0 on FIG. 4. the index n in equation (8) determines how the α scale varies with the radius of the core area, and Δ α controls the magnitude or intensity of the change.

First, a constant α value α for a particular peak wavelength is defined in equation (9) below₀Distribution of (2).

Then, a local correction or perturbation of the α value at each position r along the radius of the core region is introduced to widen the peak width or bandwidth window the local correction or perturbation of the α value depends on the delta value defined by equation (9), which is expressed in equation (10).

α(r)＝2.0557+0.0263·Δ₀(r)+δ (10)

According to an alternative embodiment, equation (4) is combined with equation (10) to obtain equation (11). the radial dependence of α in the core region may follow equation (11):

in one embodiment utilizing the relationships set forth in equation (11), an MMF is disclosed, wherein α₀Is 2.082 and the value of δ is 0.00585.

In some embodiments, if the refractive index profile of the core region has a radial dependence α given by any of equation (8), equation (9), equation (10), or equation (11), then the mode bandwidth of the MMF at longer wavelengths (e.g., wavelengths above the peak wavelength) is greater than the mode bandwidth of a comparative MMF at the same wavelengths, which is a constant α value, the average mode bandwidth of the fiber at 850nm to 950nm is at least 10% greater than the average mode bandwidth of the comparative fiber at 850nm to 950nm₀Further, the mode bandwidth of the optical fiber at 950nm is at least 10% greater than the mode bandwidth of the comparative optical fiber at 950nm in some embodiments of the foregoing aspects of multimode optical fiber, the mode bandwidth of the optical fiber at 950nm is at least 12% greater than the mode bandwidth of the comparative optical fiber at 950nm in some embodiments of the foregoing aspects of multimode optical fiber, the mode bandwidth of the optical fiber at 950nm is at least 14% greater than the mode bandwidth of the comparative optical fiber at 950nm in some embodiments of the foregoing aspects of multimode optical fiber, the mode bandwidth of the optical fiber at 950nm is at least 16% greater than the mode bandwidth of the comparative optical fiber at 950nm in some embodiments of the foregoing aspects of multimode optical fiber, the mode bandwidth of the optical fiber at 950nm is at least 18% greater than the mode bandwidth of the comparative optical fiber at 950nm in some embodiments of the foregoing aspects of multimode optical fiber, the mode bandwidth of the optical fiber at 950nm is at least 20% greater than the mode bandwidth of the comparative optical fiber at 950nm in some embodiments of the radial dependence of α, in some embodiments of α, the radial dependence of the invention₀May be in the following ranges: about 1.9 to 2.3, about 1.9 to 2.2, about 1.9 to 2.1, about 1.9 to 2.0, about 2.0 to 2.3, about 2.0 to 2.2, about 2.0 to 2.1, about 2.1 to 23, about 2.1 to 2.2, or about 2.2 to 2.3, Δ α may be in the range of about 0.005 to 0.08, about 0.006 to 0.07, about 0.007 to 0.06, about 0.008 to 0.05, or about 0.01 to 0.04, the radial position R in the core region may be 0 to R, and Δ α may be in the range of 0 to R_{1 max}The peak refractive index change at the center of the core region where r is 0.

The core preforms for manufacturing optical fibers and the manufacturing and processing methods for manufacturing optical fibers in the present disclosure are generally intended for broadband multimode optical fibers (MMF). As used herein, the terms "broadband multimode fiber" and "broadband MMF" are used interchangeably and refer to a multimode fiber having a bandwidth of at least 2GHz-km at all wavelengths in a sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth of at least 2GHz-km at all wavelengths in a sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth of at least 2GHz-km at all wavelengths in a sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth of at least 2GHz-km at all wavelengths in a sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth of at least 2GHz-km at all wavelengths in the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 2.5GHz-km at all wavelengths in the sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 2.5GHz-km at all wavelengths in the sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 2.5GHz-km at all wavelengths in the sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 2.5GHz-km at all wavelengths in the sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 2.5GHz-km at all wavelengths in the 800-1000nm wavelength range. In some embodiments, the broadband MMF has a bandwidth ≧ 3GHz-km at all wavelengths in the sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3GHz-km at all wavelengths in the sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3GHz-km at all wavelengths in the sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3GHz-km at all wavelengths in the sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3GHz-km at all wavelengths in the 800-1000nm wavelength range. In some embodiments, the broadband MMF has a bandwidth ≧ 3.5GHz-km at all wavelengths in the sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3.5GHz-km at all wavelengths in the sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3.5GHz-km at all wavelengths in the sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3.5GHz-km at all wavelengths in the sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 3.5GHz-km at all wavelengths in the 800-1000nm wavelength range. In some embodiments, the broadband MMF has a bandwidth ≧ 4GHz-km at all wavelengths in the sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4GHz-km at all wavelengths in the sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4GHz-km at all wavelengths in the sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4GHz-km at all wavelengths in the sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth of 4GHz-km at all wavelengths in the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4.5GHz-km at all wavelengths in the sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4.5GHz-km at all wavelengths in the sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4.5GHz-km at all wavelengths in the sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 4.5GHz-km at all wavelengths in the sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth of 4.5GHz-km at all wavelengths in the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 5GHz-km at all wavelengths in the sub-window of at least 50nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 5GHz-km at all wavelengths in the sub-window of at least 75nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 5GHz-km at all wavelengths in the sub-window of at least 100nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 5GHz-km at all wavelengths in the sub-window of at least 150nm between the wavelength range of 800-1000 nm. In some embodiments, the broadband MMF has a bandwidth ≧ 5GHz-km at all wavelengths in the 800-1000nm wavelength range.

The radial dependence of the distribution α may be achieved by controlling the Ge doping Profile in a chemical vapor deposition process, such as Outer Vapor Deposition (OVD), axial vapor deposition (VAD), Modified Chemical Vapor Deposition (MCVD), plasma chemical vapor deposition (PVCD), or combinations thereof, the Ge concentration is controlled based on the target graded α distribution of the present disclosure the refractive index variation in the core region of the Optical fiber follows the α distribution, which is proportional to the Ge concentration, thus, as the radial position in the Optical fiber increases from the center to the outer radius, the Ge concentration decreases from a greater Ge concentration at the center of the core region to a lesser Ge concentration at the outer radius, the Ge concentration provides a target graded Profile of the Optical fiber 64, which is measured using a preform analyzer and is compared to the target graded α distribution, the observed refractive index Profile is provided with the target graded index Profile, and is adjusted with the same or with the same index Differential Profile as the refractive index Profile in the manufacturing process, such as the refractive index Profile is measured in the same radial direction as the target Profile of the DMD, the refractive index Profile is measured in the same as the target Profile of the DMD, the index Profile of the DMD, the Optical fiber, the index Profile is measured in the same as the central graded Profile of the central Optical fiber, the central graded Profile of the central fiber, the central Profile of the central fiber, the central graded Profile, the central Profile of the central fiber, the central Profile of the Optical fiber, the central Profile of the Optical fiber, the central Profile of the Optical fiber, the central Profile of the Optical fiber, the central Profile of the central Profile, the central fiber, the central Profile of the central Profile, the central Profile of.

MMFs having a radially varying α value in the core region including a radially dependent α distribution are disclosed herein to include, but are not limited to, increased EMB for all wavelengths in the range of 850nm to 950nm, less complicated manufacturing process due to the use of a single dopant in the core region, and reduced cost of manufacturing MMFs due to the use of a single dopant in the core region.

As shown in fig. 1, the multimode optical fiber 10 includes a silica-based core 20 and a silica-based cladding (or cladding) 200 surrounding and directly adjacent to (i.e., contacting) the core 20. The numerical aperture NA of the fiber 10 may be between 0.15 and 0.25, preferably between 0.185 and 0.215. Preferably, the bandwidth of the fiber 10 is greater than 2GHz-km, with the peak bandwidth centered at wavelengths between 800nm and 1000 nm.

As shown in fig. 1A, including a maximum refractive index Δ 1_{Maximum of}The core 20 of the multimode optical fiber 10 of (a) extends from a centerline of R-0 to an outermost core radius R1, said R1 typically being about 12-30 μm, and in some embodiments 23.5-26.5 μm. The cladding 200 extends from a radius R1 to an outermost cladding radius R_{Maximum of}And has a relative refractive index Δ 4. In some embodiments, the cladding 200 has an inner cladding 30 with a relative refractive index Δ 2, an outer radius R2, and a width W2, W2 ═ R2-R1. In some embodiments, cladding 200 of optical fiber 10 includes silica-based region 50 having a relative refractive index Δ 3_{Minimum size}A minimum radius R3, an outer radius R4, a maximum width W5 ═ R4-R2, and a minimum width W4 ═ R4-R3, the silica-basedRegion 50 surrounds the core and has a refractive index lower than that of silicon dioxide due to the doping with the negative dopant. The silica-based cladding region 50 (interchangeably referred to in this disclosure as "trench 50" and "moat 50"), for example, may comprise F and optionally GeO₂. In some embodiments, the silica-based cladding region 50 includes a random or non-periodic distribution of voids (e.g., filled with a gas). The trench region 50 includes an index of refraction lower than the outer cladding 60 (e.g., at R4 and R)_{Maximum of}In between) refractive index. In some embodiments, silica-based region 50 extends through the entire cladding layer 200. In other embodiments, an outer cladding 60 surrounds the cladding region 50. In some embodiments, the cladding 200 of the optical fiber 10 includes a silica-based region 50 surrounding the core and having a refractive index Δ 3_{Minimum size}Which is lower than the relative refractive index delta 4 of the outer cladding 60. Some embodiments of optical fiber 10 also include primary and secondary polymer coatings (not shown in FIG. 1A) surrounding optical fiber 10.

In some embodiments, an optional inner silica-based cladding 30, typically containing a negative dopant, is located between the core 20 and the silica-based region 50. Fig. 1A depicts a schematic relative refractive index profile of a multimode optical fiber 10. In some embodiments, the silica-based region 50 is offset from the core 20 by a width W2-R2-R1, and is configured such that the region 50 begins at R-R2 and ends at R-R3 and has a width W3-R3-R2. In other embodiments, the silica-based region 50 is directly adjacent to the core 20 and has a rectangular or trapezoidal cross-section.

Referring again to FIG. 1A, cladding layer 200 extends from R₁Extending to the outermost cladding radius R₄. In some embodiments, the cladding layer 200 comprises Ge-F co-doped silica (e.g., in the inner cladding layer 30). In some embodiments, cladding layer 200 comprises F-doped silica (e.g., in trench region 50). For example, in some embodiments, the trench region 50 is surrounded by a silicon dioxide based outer cladding 60 (e.g., a pure silicon dioxide outer cladding or an undoped silicon dioxide based outer cladding). In some embodiments, the cladding 200 is one or moreThe coating 210 (see fig. 1) is surrounded, for example by an acrylate polymer.

The multimode optical fiber 10 includes a core region 20 and a cladding 200. The core region 20 and the cladding 200 may comprise silica. The core 20 may be doped with GeO₂And the cladding 200 may be doped with fluorine. The core region 20 has an outer radius R. The cladding 200 surrounds the core region 20.

For example, FIG. 2 shows the modal bandwidth of two comparative MMFs, comparison fiber A has the maximum modal bandwidth at 850nm, therefore, as the wavelength of light increases from 850nm, the modal bandwidth of comparison fiber A decreases somewhat, comparison fiber B has the maximum modal bandwidth at 880nm, comparison fiber A and comparison fiber B have the same profile or peak shape, comparison fiber B therefore has a modal bandwidth at a higher wavelength (e.g., 950nm) that is greater than the modal bandwidth of comparison fiber A at a higher wavelength, the shift in wavelength associated with the maximum modal bandwidth of MMF is achieved by decreasing the value of α, which balances the modal bandwidth at wavelengths greater than or equal to 850nm, while comparison fiber B has an increase in modal bandwidth at a higher wavelength (e.g., 950nm), comparison fiber B has a decreased modal bandwidth at wavelengths below 880nm (e.g., 850nm), peak width, profile and/or peak shape depend largely on the dispersion of the material, therefore, decreasing the value of α does not cause the curve to widen, thus, the peak width of comparative fiber A has a peak width corresponding requirements of 353-4 MHz at the same time as MMF having a narrow peak width window of 2483-953-6300 MHz.

The present disclosure provides an improved MMF that can conform to OM4 and OM5 standards and reduce manufacturing costs and increase manufacturing yield.lowering α values can provide a DMD centroid that is left tilted or average delay.thus, at the optimal wavelength (e.g., the wavelength associated with the maximum mode bandwidth), the Higher Order Mode (HOM) of the DMD centroid can be slightly dominant because of the locally lower α values at the outside of the core region, which can prevent the DMD centroid from being over-tilted to the right at longer wavelengths.providing lower α values at each location along the radius offset from the center of the core region can have a smaller or negligible effect on the peak wavelength (e.g., the wavelength associated with the maximum mode bandwidth) while having a significant effect or benefit of increasing the mode bandwidth at longer wavelengths (e.g., 950 nm). In other words, the HOM of the MMF exhibits a wider delay reduction relative to other portions of the MMF, thus increasing the mode bandwidth.

Referring now to FIG. 3, which is a graph illustrating the effective modal bandwidth versus wavelength plot of three exemplary optical fibers of the present disclosure and shows a comparative optical fiber, the optical fiber includes a comparative optical fiber that is a comparative fiber having a constant α profile in the core the optical fibers 1-3 are exemplary optical fibers 10 that include a α profile in the core 20, the α profile varying with radial position in the core 20. the comparison of the comparative optical fiber to the optical fibers 1-3 shows a sharp increase in the modal bandwidth of the optical fiber 10 at the peak wavelength. additionally, the peak width and the modal bandwidth at 950nm increase when the comparative optical fiber is compared to the optical fibers 1-3. the change in the α profile disclosed herein and the manufacturing yield of broadband MMF is significantly increased by expanding the refractive index profile.

In embodiments where core region 20 has a refractive index profile with a radial dependence α (e.g., fibers 2-4), α₀May be in the range of about 1.7 to about 2.3, about 1.7 to about 2.2, about 1.7 to about 2.1, about 1.7 to about 2.0, about 1.7 to about 1.9, about 1.7 to about 1.8, about 1.8 to about 2.3, about 1.8 to about 2.2, about 1.8 to about 2.1, about 1.8 to about 2.0, about 1.8 to about 1.9, about 1.9 to about 2.3, about 1.9 to about 2.2, about 1.9 to about 2.1, about 1.9 to about 2.0, about 2.0 to about 2.3, about 2.0 to about 2.2, about 2.0 to about 2.1, about 2.1 to about 2.3, about 2.1 to about 2.2 or about 2.2 to about 2.3.10.7 may be in a radial mode having a dependency between about 0.06, about 0 to about 0.06, about 0.3, about 2.3, about 3, or about 3.3.3.3, may be in a radial mode having a dependency between about 0.06, from about 0, 0.06, about 0.3, may be in a radial mode of about 0.3, including a radial mode of.

According to some embodiments, the average modal bandwidth of the fiber 10 at 950nm is at least 1.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 1.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 1.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 1.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 1.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 1.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 1.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.0 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.1 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.2 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 2.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.0 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.1 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.2 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 3.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.0 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.1 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.2 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 4.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 950nm is at least 5.0 GHz-km.

In some embodiments, the optical fiber 10 may have a peak wavelength λ of the optical fiber 10_{Maximum of}In the range of 850nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 860nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 870nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 880nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 890nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 900nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 910nm to 920 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 850nm to 910 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 850nm to 900 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 850nm to 890 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 850nm to 880 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 850nm to 870 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 850nm to 860 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 860nm to 910 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range of 870nm to 900 nm. In some embodiments, λ of the optical fiber 10_{Maximum of}May be in the range 880nm to 890 nm.

In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 2.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 2.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 2.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 2.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 2.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.0 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.1 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.2 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 3.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.0 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.1 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.2 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.5 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.6 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.7 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.8 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 4.9 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 5.0 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 5.1 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 5.2 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 5.3 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 5.4 GHz-km. In some embodiments, the average modal bandwidth of fiber 10 at 850nm is at least 5.5 GHz-km.

In some embodiments, the relative refractive index of the core 20 of the optical fiber 10 is 0.9% to 1.1%. In some embodiments, the relative refractive index of the core 20 of the optical fiber 10 is 0.9% to 1.2%. In some embodiments, the relative refractive index of the core 20 of the optical fiber 10 is 0.9% to 1.3%. In some embodiments, the relative refractive index of the core 20 of the optical fiber 10 is 0.8% to 1.2%. In some embodiments, the relative refractive index of the core 20 of the optical fiber 10 is 0.7% to 1.3%. In some embodiments, the outer radius R of the core 20 is from about 10 μm to about 30 μm. In some embodiments, the outer radius R of the core 20 is about 11 μm to about 29 μm. In some embodiments, the outer radius R of the core 20 is about 12 μm to about 28 μm. In some embodiments, the outer radius R of the core 20 is about 13 μm to about 27 μm. In some embodiments, the outer radius R of the core 20 is about 14 μm to about 27 μm. In some embodiments, the outer radius R of the core 20 is about 14 μm to about 26 μm. In some embodiments, the outer radius R of the core 20 is about 15 μm to about 25 μm. In some embodiments, the outer radius R of the core 20 is about 16 μm to about 24 μm. In some embodiments, the outer radius R of the core 20 is about 17 μm to about 23 μm. In some embodiments, the outer radius R of the core 20 is about 18 μm to about 22 μm. In some embodiments, the outer radius R of the core 20 is about 19 μm to about 21 μm.