Optical fiber (options)


G02B6/16 -

 

The invention is used in fiber-optic communication lines. Optical fiber contains a layer with a high concentration of Germany, located in the center of the optical fiber and having a concentration of oxide Germany 0.1 wt.% or more relative to the total mass of the layer with high GE concentration, and the layer with low GE concentration, set around a layer with a high concentration and containing an oxide of germanium with a concentration of less than 0.1 wt.% respect to the total mass of the layer with low GE concentration. In the first embodiment, the scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration used in the band of wavelengths equal to 0.4% or less relative to the total optical power propagated through the optical fiber. For the second option, the outer diameter of the layer with high GE concentration of at least 2.6 times the diameter of the field of fashion in the used range. The increase of vodorodostojkih fiber. 2 S. and 4 C.p. f-crystals., 1 table, 12 Il.

Field of invention the Invention relates to optical fiber having improved characteristics vodorodostojkih.

Prelestna, made of quartz glass, which is important for transmission of optical fibers.

In Fig. 11 depicts a graph showing the dependence of the losses as a function of wavelength before and after exposure to hydrogen at ordinary optical fiber under conditions when it is exposed to 100% hydrogen at a temperature of 30oC for 21 hours. In the following description, the optical fiber is exposed to hydrogen under the same conditions.

In Fig.11, the curve a shows the magnitude of the losses prior to the impact, and curve b shows the magnitude of the losses after exposure. In order to clarify the effects of hydrogen, the increase in loss before and after exposure to hydrogen shown by curve C in Fig.12.

As a result of exposure to hydrogen forming a high peak increase losses near 1530 nm, and low peak increase of losses is obtained near 1580 nm. As described below, the peak near 1580 nm is due only to the influence of hydrogen, and the peak near 1530 nm caused a total effect of hydrogen and peroxyl radicals existing in the optical fiber, as described below.

Curve D shows the increase in losses calculated by subtracting the increase in losses caused only by exposure to hydrogen,W is relatively high peak near 1530 nm.

As the wavelength used for numerous purposes, in a conventional optical communication system is in a so-called band with band With (from 1530 to 1560 nm), the consecutive changes of the losses caused by exposure to hydrogen near 1530 nm, significantly affect the transmission characteristics of optical fibers.

In recent years, often used systems division multiplexing wavelengths (MRDV (WDM)) that use a range with a Central wavelength of 1550 nm.

In these systems, pre-amplification system is used, which compensates for the loss characteristics of optical fibers in a wide range, for example from 1530 to 1560 nm.

However, when the characteristics of the loss at the operating wavelength change over time due to the penetration of hydrogen into the optical fiber amplification system could not compensate the loss characteristics at the working wavelength of the optical fiber, which thus results in a significant impact on the entire system.

Peak losses near 1530 nm is formed as a result of the following effects.

When peroxyl the relationship expressed by the following chemical formula:Si-O-OChemical formula 2 in the optical fiber obtained by melting and extrusion of the preform of the optical fiber under certain conditions. When hydrogen enters this optical fiber, it reacts with peroxyl radicals, gives the group Si-O-O-H, which causes losses near the wavelength of 1530 nm. In the end, the group Si-O-O-H loses an oxygen atom, forming a group Si-OH, which absorbs at the wavelength of 1380 nm. After the formation of the group Si-OH even when it is exposed to hydrogen absorption at the wavelength of 1530 nm is not happening.

In order to suppress the increase of the losses, a method in which the conditions for melting and extruding optimized to reduce the formation of peroxyl radicals in the optical fiber. In addition, a method in which the optical fiber is pre-processed in a hydrogen atmosphere.

However, these methods have various disadvantages, which are that there are restrictions on the production equipment, the Finance structure of the optical fiber. For example, in Japanese provisional patent application, first publication Hei 9-15464 described optical fiber that includes a core obtained by sequentially laminating the layer deposited from the vapor phase, and tubular excretory layer of the shell, and a tubular pin layer of the shell has a plot for hydrogen absorption, which includes materials selected for capture of hydrogen to essentially prevent diffusion of hydrogen in the layer deposited from the vapor phase while receiving optical fiber.

However, this optical fiber has various drawbacks associated with the fact that the method of manufacture has limitations and cannot be used to obtain multi-purpose profile of the refractive index.

In Japanese provisional patent application, first publication Hei 9-171120, disclosed is an optical fiber that includes a core obtained by sequential lamination, inner layers and outer layers, in which germanium is added into the inner layer, in which the optical power is distributed from the core to prevent the formation of peroxyl relations presented above chemical formula 1 and is called the Ko in Japanese preliminary patent application, the first publication Hei 9-171120, almost vaguely described that a significant amount of light is distributed in the interior of the shell, alloyed with germanium. In addition, investigated only the specific profile of the refractive index of the optical fiber, in which the inner region of the shell and the outer region of the shell is made essentially of the same material. Therefore, the optical fiber described in Japanese preliminary patent application, first publication Hei 9-171120, you can't just apply to the different profiles of the refractive index, which is proposed in the present invention.

In particular, the gradual change losses near 1530 nm leads to negative impact on the system MRDV. On the contrary, although the proposed optical fiber having a relatively complex profile of the refractive index, and is intended for use in the system MRDV remain difficulties associated with implementing this complex profile of refractive index in a known way and ensure a stable system.

Summary of the invention the Present invention is made taking into account features described above. The present invention is to provide an optical oxen providing optical fiber, which is suppressed peak losses, especially near the wavelength of 1530 nm, caused by the relationship between peroxyl radicals and hydrogen.

In addition, the present invention provides an optical fiber that can be used with different profiles of the refractive index and has the feature of vodorodostojkih, in which the suppressed peak losses, especially near the wavelength of 1530 nm.

In order to eliminate the shortcomings described above, the present invention provides an optical fiber containing layer with a high concentration of germanium and a layer with low GE concentration, in which the layer with high GE concentration is located in the center of the optical fiber and contains an oxide of germanium with a concentration of 0.1 wt.% or more relative to the total mass of the layer with a high concentration of germanium, the layer with low GE concentration is around layer with high GE concentration and contains an oxide of germanium with a concentration of less than 0.1 wt.% respect to the total mass of the layer with low GE concentration, and the scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration used in processee fiber.

In addition, the present invention provides an optical fiber containing layer with a high concentration of germanium and a layer with low GE concentration, in which the layer with high GE concentration is located in the center of the optical fiber and contains an oxide of germanium with a concentration of 0.1 wt. % or more relative to the total mass of the layer with a high concentration of germanium, the layer with low GE concentration is around layer with high GE concentration and contains an oxide of germanium with a concentration of less than 0.1 wt. % relative to the total weight of the layer with low GE concentration, and the outer diameter of the layer with high GE concentration of at least 2.6 times the diameter of the field of fashion in the band of wavelengths.

In the optical fiber layer with low GE concentration may include a shell layer with high GE concentration may include a core and an intermediate layer located between the core and the shell, and the maximum value of the refractive index of the core can be 0.25% or much higher than that of the intermediate layer.

In the layer of optical fibers with a high level of concentration, Germany, together with the oxide germansorrente illustrated by reference to the accompanying drawings, in which: Fig. 1A and 1B schematically depict the structure of an optical fiber according to the first variant implementation of the present invention;
Fig.1C depicts the profile of the refractive index of the optical fiber;
Fig. 1D depicts the distribution of the concentration of oxide of Germany in the optical fiber;
Fig.2A and 2B schematically depict the structure of an optical fiber according to the second variant of implementation of the present invention;
Fig.2C depicts the profile of the refractive index of the optical fiber;
Fig. 2D depicts the distribution of the concentration of oxide of Germany in the optical fiber;
Fig. 3A-3C depict the profiles of the refractive index of the optical fibers used to verify the dependence of peak losses from scattering coefficient of optical power;
Fig. 4 depicts a graph showing the dependence of the peak losses from scattering coefficient of optical power;
Fig. 5A depicts a graph showing the profile of the refractive index of the optical fiber in example 1;
Fig.5B depicts a graph showing the distribution of the concentration of oxide of Germany in the optical fiber;
Fig. 6 depicts a graph showing the dependence of the increase of losses in Optiline optical fiber in example 2;
Fig.7B depicts a graph showing the distribution of the concentration of oxide of Germany in the optical fiber;
Fig. 8 depicts a graph showing the dependence of the increase of losses in the optical fiber of example 2 as a function of wavelength;
Fig. 9A depicts a graph showing the profile of the refractive index of the optical fiber in example 3;
Fig.9B depicts a graph showing the distribution of the concentration of oxide of Germany in the optical fiber;
Fig. 10 depicts a graph showing the dependence of the increase of losses in the optical fiber of example 3 as a function of wavelength;
Fig. 11 depicts a graph showing the dependence of the loss of traditional optical fiber as a function of wavelength before and after exposure to hydrogen;
Fig. 12 depicts a graph showing the dependence of the increase in losses as a function of wavelength, which is calculated by subtracting the magnitude of the increase in losses caused only by exposure to hydrogen, the amount of the increase of the losses of the optical fiber before and after exposure to hydrogen, which is shown in Fig.11.

Detailed description of the invention
In the present invention is used band of wavelengths selected in accordance with the designated purpose: for example, choose and what areas with the band (from 1530 to 1560 nm), above.

The present invention will be explained in detail by means of two embodiments.

(1) the First version of the implementation
In Fig. 1A-1D shows the optical fiber having the profile of the refractive index of the segmented core, which is obtained by using method axial deposition from vapor phase (BPA (VAD)).

Although the actual profile of the refractive index has a rounded peak and the shape of the basin of Fig.1C shows a typical example of the profile of the refractive index. The profile of the refractive index is intended to increase the effective area of the cross section of the core (AEF), the required transmission lines MTV, and is suitable for suppressing the dispersion slope.

This optical fiber consists of a layer 1 with a high concentration of Germany, including 0.1 wt. percent or more of oxide, Germany and layer 2 with low concentrations of Germany, with less than 0.1 wt.% oxide Germany, which is located around the layer 1 with a high concentration of germanium and has a constant profile of the refractive index.

Below is a description of the upper limit of the concentration of oxide in Germany, which is contained in the layer 1 with a high concentration of germanium. The lower limit of concentrate implementation in pure quartz glass as a dopant add only the oxide Germany. Since germanium increases the refractive index, which is shown in Fig.1C for the profile of refractive index, and Fig.1D for the concentration distribution of the oxide Germany, the picture of the profile of the refractive index identical to the picture of the concentration distribution of the oxide Germany, and the refractive index of the layer 1 with a high concentration of germanium is higher than that of the layer 2 with low concentrations of Germany.

Layer 1 with a high concentration of Germany consists of the core 7, which includes the Central core 3 formed by laminating from the center position of the intermediate part 4 and the ring core 5, and the intermediate layer 6 formed on the circumference of the core 7.

Layer 2 with low concentrations of Germany consists of the shell 8. The intermediate layer 6 is formed between the core 7 and the casing 8.

The refractive index in the intermediate part 4 is lower than in the Central core 3, and the refractive index in the ring core 5 is lower than in the Central core 3, and higher than in the intermediate part 4.

The refractive index of the intermediate layer 6 is gradually reduced outward and becomes almost identical at the boundary between the intermediate layer 6 and layer 2 with nisi concentration of Germany includes the inner layer 2A and the outer layer 2b. Layer 1 with a high concentration of germanium and the inner layer 2A is produced by the process of steps according to the method of BPA. The outer layer 2b was produced using the method of external deposition from the vapor phase, in which particles of silicon dioxide are deposited on the outside of the inner layer 2A.

In conventional optical fiber Central region, where the refractive index is high, is the area of the core and the area around the area of the core, in which the distribution of refractive index is maintained almost at a constant level, and the refractive index is lower than in the core area, is the area of the shell. In this embodiment, the core area includes the area from the Central core 3 to the ring core 5, and the shell region includes the area of the layer 2 with low concentrations of Germany. In addition, between the core 7 and layer 8 is formed intermediate layer 6.

In order to use optical fiber as a transmission line, the relative difference between the refractive indices is determined by the formula
=(nt-nprom.CL.)/nprom.CL.100(%)

The maximum value of the refractive index of the core 7 is not specifically limited. For example, although the relative difference between the refractive indices of the optical fiber used for transmission MRDV, usually set equal to 1.0% or less, the relative difference between the refractive indices of the optical fiber is used to compensate for dispersion, can be set at the level of more than 1.0%.

Thus, the intermediate layer 6, in which the maximum value of refractive index lower than the core 7, is formed between the layer 1 with a high concentration of germanium and a layer 2 with a low GE concentration, and refractive index and diameter of the intermediate layer 6 regulate regardless of the core 7 in order to control the scattering coefficient of optical power from the layer 1 with a high concentration of germanium in the layer 2 with a low GE concentration, while maintaining the required optical characteristics.

The preferred condition is that the refractive index and the distribution of the refractive index of the intermediate layer 6 can be controlled with appropriate optical fiber with the desired optical characterististics longer, that may cause undesired broadening in the distribution of refractive index. Thus, you may have managed the refractive index of the intermediate layer 6.

The outer diameter of the core 7 and the width of the intermediate layer 6 can be determined in accordance with the desired refractive index or the necessary distribution of the electric field caused by the refractive index, and can be appropriately changed in accordance with the required conditions.

In Fig.1C and 1D by curves E(r) shows the broadening of the electric field in the optical fiber at the wavelength of 1550 nm in the band of wavelengths. As shown in these drawings, although the light is mainly distributed in the center of the optical fiber, i.e. in the layer 1 with a high concentration of Germany, a little light scatters near layer 1 with a high concentration of Germany, i.e. in the layer 2 with low concentrations of Germany.

In the optical fiber according to the present invention, the scattering coefficient of optical power from the layer 1 with a high concentration of germanium in the layer 2 with a low GE concentration is set at the level of 0.4% or less, and more preferably 0.2% or less relative to the full op is x research as described below, when the scattering coefficient of an optical power of more than 0,4%, it becomes impossible to improve the characteristics of vodorodostojkih.

The scattering coefficient of optical power can alternatively be represented by the diameter of the field of fashion (PDM), which shows the magnitude of the electric field of the light propagating through the optical fiber. That is, the outer diameter D of the layer 1 with a high GE concentration set at least 2.6 times greater, more preferably at least 2.8 times the PDM, to form the same structure that was obtained by selection of the scattering coefficient of optical power, equal to 0.4% or less, more preferably of 0.2% or less as described above. Among these conditions imposed on the scattering coefficient of optical power and an external diameter D, is that when first performed, then the other is required.

Therefore, the optical fiber according to the present invention can be characterized by the scattering coefficient of optical power or the ratio of the outer diameter D of the layer 1 with a high concentration of Germany to the PDM, which is selected in accordance with the required conditions.

CoE is m refractive index layer 1 with a high concentration of germanium. The profile of the refractive index includes an outer diameter or refractive index of each layer. Because the values of the refractive index profile of the refractive index is changed in accordance with the used band of wavelengths, it is preferable to install a pre-selected optimum conditions used in the band of wavelengths.

(2) the Second variant implementation
In Fig.2A-2D shows the type of optical fiber with a segmented core obtained by the method of modified chemical vapour deposition (MHOPF (MCVD)). Among the structures shown in Fig.2A-2D, a structure identical to the structure shown in Fig.1A-1D, are denoted by the same positions as in Fig.1A-1D, and their explanations are omitted.

The profile of the refractive index of the second variant implementation is similar to the profile of the refractive index of the first variant implementation, except that the distribution of the refractive index of the intermediate layer 6' around the ring core 5 is maintained at a constant level, which is aligned with the refractive index of the layer 2 with a low concentration of germanium (shell 8).

In accordance with the method MHOPF source quartz tube, for example, g is s, and the like in the vapor phase and heated to start the reaction with each other through the burner, located outside the quartz tube. In the result, particles of silicon dioxide, the particles of germanium dioxide and the like deposited on the inner wall of the original quartz tube, forming in the preparation of the optical fiber.

As shown in Fig.2A and 2B, the layer 2 with low concentrations of Germany consists of the original quartz tube 2d, the inner layer 2C formed inside the original quartz tube 2d, and the outer layer 2E formed outside the source quartz tube 2d. Layer 1 with a high concentration of germanium and the inner layer 2C is formed inside the original quartz tube 2d way MHOPF, and the outer layer 2E is formed by way of the external vapour deposition.

In Fig.2C shows the profile of the refractive index, and Fig.2D shows the distribution of the concentration of oxide Germany. In layer 1 with a high concentration of germanium fluoride, which reduces the refractive index, add together with oxide of Germany.

The profile of the refractive index of the layer 1 with a high concentration of germanium is approximately proportional to the concentration of oxide, Germany, and the refractive index of the intermediate layer 6' agrees with the refractive index of the layer 2 with a low concentration of g is the beginning of layer 1 with a high concentration of germanium in the layer 2 with a low GE concentration is 0.4% or less, and more preferably of 0.2% or less relative to the total optical power propagating through the optical fiber in the same manner as described in the first embodiment. Outer diameter D of the layer 1 with a high GE concentration of at least 2.6 times more PDM, more preferably at least 2.8 times the PDM.

As described above, to control the refractive index of each layer add fluoride. Therefore, the fluorine can be added only to that part of the layer 1 with a high concentration of Germany, in which it is necessary to reduce the refractive index, or alternatively all part of the layer 1 with a high concentration of germanium and adjusting the amount of added fluorine. In this case, the concentration of the added fluoride is not restricted and can appropriately be determined in consideration of a specific use.

Doping the impurity, which can be added to layer 1 with a high concentration of Germany, is not limited to fluorine, and various elements such as boron, can be used as a dopant. Since germanium has the effect of increasing the refractive index, and the fluorine is usually known as a material having the effect of decreasing pokazatelaya impurities together with oxide of Germany is possible to obtain an optical fiber, with a complex profile of the refractive index. For example, the part having a lower refractive index than that of the shell 8, can be formed within layer 1 with a high concentration of germanium. In addition, it is possible to suppress the increase of the refractive index in the intermediate layer 6', which is caused by the addition of Germany, and you can control the scattering coefficient of optical power in layer 2 with a low GE concentration without affecting the optical characteristics, which are determined using the distribution of refractive index in the core 7.

Although the above describes only one example in which the fluorine added together in the optical fiber obtained by the method MHOPF, fluorine can be added together in the optical fiber obtained by another method, such as method of BPA or similar.

In the description below, the relationship between the scattering coefficient of optical power from the layer 1 with a high concentration of germanium in the layer 2 with a low GE concentration and peak losses near 1530 nm, which is caused by exposure to hydrogen will be explained in detail through research, in which indeed receive an optical fiber.

In Fig.3A-3C shows the profiles of indicator prisposoba MHOPF, which was used above in the second embodiment.

In Fig.3A, the refractive index in the intermediate part 4, the intermediate layer 6' and the layer 2 with low concentrations of Germany, which is located outside the intermediate layer 6', identical to each other. In Fig.3B, the refractive index in the intermediate layer 6' and the layer 2 with a low GE concentration identical to each other, and the refractive index of the intermediate part 4 is higher than that of the intermediate layer 6' and the layer 2 with low concentrations of Germany. In Fig.3C, the refractive index of the intermediate layer 6' and the layer 2 with a low concentration of germanium (shell 8) identical to each other, and the refractive index of the intermediate part 4 is lower than that of the intermediate layer 6' and the layer 2 with low concentrations of Germany. In order to obtain an optical fiber having different distribution profiles of the refractive index, the fluorine added together in layer 1 with a high GE concentration in the intermediate layer 6' as necessary.

In the present invention the upper limit of the added oxide Germany is not limited to a particular way in parts, such as the Central core 3 and the ring core 5, where the refractive index is wise.% in such parts, as the intermediate portion 4 (Fig.3C), in which the relative difference of the refractive indices, based on the refractive index of the layer 2 with low concentrations of Germany, less than or equal -0,1%. When the amount of oxide Germany, want to add is in the range from 0.1 to 1.0 wt.%, it is possible to improve the characteristics of vodorodostojkih. When the amount of oxide of Germany, which will add more than 1.0 wt.%, optical losses increase considerably due to losses in the Rayleigh scattering caused by excessive number of Germany. When fluorine is added in order to reduce the refractive index, which is increased by the addition of 1.0 wt.% or more in Germany, the amount of added fluorine increases, which also leads to a significant increase in optical loss caused by losses due to Rayleigh scattering.

The table shows the number of pieces corresponding to the profile of the refractive index have made four optical fibers (samples 1-4) and the measured values of the optical characteristics of the four optical fibers.

In Fig. 4 depicts a graph showing the dependence of the maximum loss that occurs near 1530 nm after exposure to Lodore low concentrations of Germany to the full optical power [PSiO2/Pfull(%)].

Optical power dissipation PSiO2and full optical power Pfulldetermined using the following formula:


(where r is the radius, E(r) is the electric field distribution,Legerconsistentis the radius of the layer with high GE concentration, and rshell- half the thickness of the shell).

As shown in this graph, the dissipation factor [PSiO2/Pfull(%)] is proportional to the magnitude of the peak losses. The peak value of the losses is preferably small. When the peak value of the loss is 0.01 dB/km or less, more preferably of 0.005 dB/km or less, it is possible to suppress the influence on the transmission characteristics and in General on all fiber-optic system to a degree that makes fiber optic quite high-tech.

As shown in this graph, the ratio [PSiO2/Pfull(%)] can be set equal to 0.4% or less in order to determine the size of the maximum loss is equal to 0.01 dB/km or less, and the ratio [PSiO2/Pfull(%)] can be set equal to 0.2% or less in order to determine the size of the maximum loss equal to 0.005 dB/km or less. Coefficient [PSiO2/Pfull(%)] . From a performance standpoint, the upper limit of the outer diameter of the layer with high GE concentration determined according to the method of manufacture, such as the method of BPA or the way MHOPF or device for manufacturing.

As described above, the PDM can be used as a parameter, which is effective for determining the outer diameter of the layer with high GE concentration and the alternative factor [PSiO2/Pfull(%)].

Preferred ranges of values of the scattering coefficient of optical power and the relationship of the outer diameter of the layer with high GE concentration to the PDM, which are described above, are applied to the piece of optical fiber and optical fiber obtained by drawing the optical fiber preform. In particular, the way MHOPF or CVD method, the scattering coefficient of optical power and the ratio of the outer diameter of the layer with high GE concentration to PDM billet optical fibers can also be estimated rises the PE receiving the optical fiber preform.

Although the optical fiber having the profile of the refractive index type segmented core described by way of example, the type of the profile of the refractive index of the optical fiber is not specifically limited, and can be applied to various types of profile of the refractive index, for example so-called step-type, W-shaped, O-shaped ring-type or similar.

The profile of the refractive index of the stepped type, for example, consists of a Central core, obtained by lamination of a Central position, a side core and a shell, the refractive index which gradually decreases from the center of the core. The profile of the refractive index of the W-shaped type, for example, consists of a Central core, obtained by lamination of the center position of the side core and the shell, the refractive indices are set so that they decreased in the following order: Central core, the shell and the side core. The profile of the refractive index of the O-shaped ring type includes a core having two or more layers, in which the ring core is located around the Central core, and the refractive index of approx optical fibers, having such profiles of the refractive index, it is preferable to control the ratio of the scattering optical power so that he took a certain value in the present invention at the location of the intermediate layer between the core and the shell.

The optical fiber according to the present invention can be used for various purposes, such as compensation of the dispersion or the like, as well as for transmission, such as transmission MRDV.

Examples
In the following description, the optical fiber according to the present invention will be explained specifically by way of examples. All of the examples used wavelength is set to 1550 nm.

Example 1
According to the method MHOPF, blank optical fiber was obtained from quartz glass and then it was pulled optical fiber. This optical fiber had optical characteristics similar to sample 4 shown in table 1 and Fig.4.

In Fig. 5A shows the profile of the refractive index, and Fig.5B shows the distribution of the concentration of oxide Germany. In this optical fiber, the oxide of germanium and fluorine added together in the core and intermediate layer, and the respective concentrations OCI of refraction, based on the layer with low GE concentration (shell), -0,1% or less while maintaining the concentration of the oxide of Germany at the level of 0.1 wt.% or more.

The scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration was set approximately equal to 0.1% relative to the total optical power.

In this optical fiber outer diameter of the core was equal of 16.3 μm, the outer diameter of the intermediate layer was equal to 23.1 μm, and the outer diameter of the intermediate layer was approximately 2.75 times greater than that of PDM (8,4 μm).

Then, the optical fiber was subjected to hydrogen and measured its performance loss at the operating wavelength.

In Fig. 6 depicts the same graph as in Fig.12, in which the continuous line shows the amount of increase in loss after exposure to hydrogen, and the broken line shows the amount of increase in the losses calculated by subtracting the increase in losses caused only by the influence of hydrogen from increased losses after exposure to hydrogen.

The amount of increase in loss near 1530 nm, caused by the relationship between peroxyl radical and hydrogen, was 0.0001 dB/km or less, and were to the to procurement optical fiber and then it was pulled optical fiber. This optical fiber had optical characteristics are the same as in sample 3, are presented in table 1 and Fig.4.

In Fig. 7A shows the profile of the refractive index, and Fig.7B shows the distribution of the concentration of oxide Germany. In this optical fiber, so as soon as the oxide, Germany was added to the core and the intermediate layer, the profile of the refractive index and the corresponding concentration of the oxide Germany were identical to each other. The scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration was set approximately equal to 0.1% relative to the total optical power.

In this optical fiber outer diameter of the core was equal to 14.6 μm, the outer diameter of the intermediate layer was equal to 25.1 μm, and the outer diameter of the intermediate layer was approximately 2.7 times more PDM (of 9.3 μm).

Then, the optical fiber was subjected to hydrogen and measured characteristics of the loss of the optical fiber at the operating wavelength. In Fig.8 shows a graph similar to the graph shown in Fig.6. As shown in this graph, the amount of increase in loss, which is caused by the relationship between peroxyl radical and the cooking of the optical fiber and then it was pulled optical fiber. This optical fiber had optical characteristics are the same as those of sample 1 shown in table 1 and Fig.4.

In Fig. 9A shows the profile of the refractive index, and Fig.9B shows the distribution of the concentration of oxide Germany. In this optical fiber trace amount of fluorine was added together with oxide of germanium in the core and the intermediate layer and ran the appropriate concentration of the oxide of germanium and fluorine each layer.

In this optical fiber outer diameter of the core was equal to 15.7 μm, the outer diameter of the intermediate layer was equal to 24.3 μm, and the outer diameter of the intermediate layer was approximately 2.6 times more PDM (of 9.3 μm). The scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration was set approximately equal to 0.4% relative to the total optical power.

Then, the optical fiber was subjected to hydrogen and measured characteristics of the loss of the optical fiber at the operating wavelength. In Fig.10 depicts a graph similar to the graph shown in Fig.6. As shown in this graph, the amount of increase in loss, which is caused by the relationship between peroxyl radical, bodoro is s expected the outer diameter of the layer with high GE concentration can be increased in order to suppress the additional losses increase.

As described above, when installing the scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration in the range of 0.4% or less relative to the total optical power propagating through the optical fiber, or alternatively, when installing an external diameter of the layer with high GE concentration of at least 2.6 times the diameter of the field of fashion in the band of wavelengths, it is possible to improve the characteristics of vodorodostojkih optical fiber. In particular, the amount of increase in loss near 1530 nm, caused by the relationship between peroxyl radical and hydrogen, can be reduced approximately to an insignificant level.

There are no restrictions imposed on the profile of the refractive index, and you can use different profiles of the refractive index. In addition, you can use the sophisticated profile of the refractive index by adding a dopant, such as fluorine, together with oxide of germanium, at least one layer with high GE concentration, including at least the ical fiber, containing layer with a high concentration of germanium and a layer with low GE concentration, in which the layer with high GE concentration is located in the center of the optical fiber and contains an oxide of germanium with a concentration of 0.1 wt.% or more relative to the total mass of the layer with a high concentration of germanium, the layer with low GE concentration is around layer with high GE concentration and contains an oxide of germanium with a concentration of less than 0.1 wt.% respect to the total mass of the layer with low GE concentration, the scattering coefficient of optical power from a layer with a high concentration of germanium in the layer with low GE concentration used in the band of wavelengths equal to 0.4% or less relative to the total optical power propagating through the optical fiber.

2. Optical fiber under item 1, characterized in that the layer with low GE concentration includes a shell layer with high GE concentration includes a core and an intermediate layer located between the core and the shell, and the relative difference between the refractive indices is determined by the formula
=(nt-nprom.SL)/nprom.SL/>nprom.SL- the maximum refractive index of the intermediate layer.

3. Optical fiber under item 1, characterized in that the doping impurity different from the oxide Germany, is added together with oxide of germanium in the layer with high GE concentration.

4. Optical fiber containing layer with a high concentration of germanium and a layer with low GE concentration, in which the layer with high GE concentration is located in the center of the optical fiber and contains an oxide of germanium with a concentration of 0.1 wt.% or more relative to the total mass of the layer with a high concentration of germanium, the layer with low GE concentration is around layer with high GE concentration and contains an oxide of germanium with a concentration of less than 0.1 wt.% respect to the total mass of the layer with low GE concentration, the outer diameter of the layer with high GE concentration of at least 2.6 times the diameter of the field of fashion in the band of wavelengths.

5. Optical fiber under item 4, characterized in that the layer with low GE concentration includes a shell layer with high GE concentration includes a core and an intermediate layer located between the core and the shell, and /sub>-nprom.SL)/nprom.SL100(%)0, 25 (%),
where nt- maximum core refractive index;
nprom.SL- the maximum refractive index of the intermediate layer.

6. Optical fiber under item 4, characterized in that the doping impurity different from the oxide Germany, is added together with oxide of germanium in the layer with high GE concentration.

 

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The invention relates to a single-mode optical waveguide fiber, which has a wavelength zero dispersion shifted in the range of about 1550 nm, a large effective area and low slope full dispersion

The invention relates to a single-mode optical waveguide fiber with a large effective area (aefffor communication equipment

The invention relates to a single-mode optical fiber with a controlled negative full dispersion and a relatively large effective area

The invention relates to a single-mode optical waveguide fiber with a large effective area of Aefffor use in the field of communications

The invention relates to a single-mode fiber-optic waveguides with controlled dispersion and method of manufacturing such waveguides
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Scintillation fiber // 2154290

FIELD: optical and electronic industry; production of fiber optic components having electrooptical effect.

SUBSTANCE: the inventions are dealt with optical and electronic industry, and may be used for development engineering of transmitting systems and data processing, in which application of the fiber optic components with electrooptical effect is expedient. The fiber consists of a core, a light conducting shell, a light-absorbing shell containing light-absorbing elements and current-carrying electrodes. The method includes operations of a down-draw of separate glass rods from glasses fillets composing elements of a fiber, piling up a pack of a with the form of cross-section of a hexahedron or a square including piling of electrodes, afterstretching of preform and its pulling into a fiber with application of a polymeric coating. The invention allows to create a single-mode fiber with heightened electrooptical effect from the glasses having a Kerr constant by 1.5 order higher than one of a quartz glass, to produce fibers with the given structure of shells, cores and control electrodes at simplification of process of a drawing down of fibers.

EFFECT: the invention ensures creation of a single-mode fiber with heightened electrooptical effect, to produce fibers with the given structure of shells, cores and control electrodes, to simplify process of fibers drawing down.

13 cl, 9 dwg

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