WO2022149182A1 - 光ファイバ - Google Patents
光ファイバ Download PDFInfo
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- WO2022149182A1 WO2022149182A1 PCT/JP2021/000073 JP2021000073W WO2022149182A1 WO 2022149182 A1 WO2022149182 A1 WO 2022149182A1 JP 2021000073 W JP2021000073 W JP 2021000073W WO 2022149182 A1 WO2022149182 A1 WO 2022149182A1
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- core
- optical fiber
- refractive index
- channel
- optical
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 147
- 230000005540 biological transmission Effects 0.000 claims abstract description 86
- 238000009826 distribution Methods 0.000 claims abstract description 26
- 230000003287 optical effect Effects 0.000 claims description 142
- 238000004891 communication Methods 0.000 claims description 89
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 45
- 239000000835 fiber Substances 0.000 description 75
- 238000010586 diagram Methods 0.000 description 45
- 238000013461 design Methods 0.000 description 32
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 21
- 229910052731 fluorine Inorganic materials 0.000 description 21
- 239000011737 fluorine Substances 0.000 description 21
- 239000010453 quartz Substances 0.000 description 20
- 230000007423 decrease Effects 0.000 description 17
- 238000000034 method Methods 0.000 description 16
- 238000005452 bending Methods 0.000 description 10
- 238000004364 calculation method Methods 0.000 description 9
- 238000012545 processing Methods 0.000 description 7
- 239000011521 glass Substances 0.000 description 6
- 230000001427 coherent effect Effects 0.000 description 4
- 101150064974 ass1 gene Proteins 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02042—Multicore optical fibres
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02214—Optical fibres with cladding with or without a coating tailored to obtain the desired dispersion, e.g. dispersion shifted, dispersion flattened
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/02057—Optical fibres with cladding with or without a coating comprising gratings
- G02B6/02076—Refractive index modulation gratings, e.g. Bragg gratings
- G02B6/0208—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response
- G02B6/021—Refractive index modulation gratings, e.g. Bragg gratings characterised by their structure, wavelength response characterised by the core or cladding or coating, e.g. materials, radial refractive index profiles, cladding shape
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/02—Optical fibres with cladding with or without a coating
- G02B6/036—Optical fibres with cladding with or without a coating core or cladding comprising multiple layers
Definitions
- This disclosure relates to an optical fiber for optical communication.
- optical coherent communication technology In the current long-distance transmission network, a dramatic increase in capacity has been realized by optical coherent communication technology.
- information is assigned to the phase state of light. Since the phase state of the signal light changes due to the wavelength dispersion of the optical fiber constituting the transmission line and the phase fluctuation of the signal light source, the signal quality deteriorates. Therefore, in optical coherent communication, digital signal processing (DSP) for removing phase noise in the receiver is indispensable. At present, sufficient signal quality is ensured by DSP, but there is a problem that the calculation cost in the device increases.
- DSP digital signal processing
- Non-Patent Document 1 proposes a method in which one channel in a transmission channel is used as a Master channel for carrier phase estimation, and the estimation result is diverted to the other transmission channels for phase correction.
- This transmission method is called Master-Slave CPE (MS-CPE).
- MS-CPE Master-Slave CPE
- the MS-CPE can reduce the signal processing cost for phase estimation by the Slave channel.
- Non-Patent Document 2 shows the possibility of applying the transmission channel with reduced group delay time to the Master channel of MS-CPE and reducing the DSP processing delay time in the Slave channel.
- the MS-CPE of Non-Patent Document 3 uses a core and a stepped clad multi-core fiber whose refractive index distribution is reduced to about 1 ⁇ m in a transmission channel having a reduced group delay time as an optical fiber.
- the core having a reduced refractive index distribution is liable to be deformed due to the spinning tension at the time of manufacturing an optical fiber (it is difficult to obtain the desired effect of MS-CPE), and there is a problem in manufacturability.
- an object of the present invention is to provide an optical fiber with improved manufacturability for MS-CPE in order to solve the above-mentioned problems.
- the optical fiber according to the present invention uses a low delay core using a typical refractive index distribution adopted in a general-purpose optical fiber as a Master channel.
- the first optical fiber according to the present invention is an optical fiber included in an optical communication system of the MS-CPE transmission method.
- the core having a radius a ( ⁇ m) for the master channel and the clad having a specific refractive index difference ⁇ (%) with respect to the core have a step index (SI) type refractive index distribution structure and satisfy the number C1. It is characterized by that.
- ⁇ (ns / km) is a group delay time difference between the master channel and the slave channel, and is a signal arrival time difference s ( ⁇ s) when an optical signal is transmitted between the master channel and the slave channel of the optical communication system.
- the transmission distance L (km) of the optical signal it is a value satisfying the number C2.
- the second optical fiber according to the present invention is an optical fiber included in the MS-CPE transmission type optical communication system.
- the clad having a rate difference of ⁇ 2 (%) has a W-type refractive index distribution structure, and is characterized by satisfying the number C3.
- MFD is the mode field diameter ( ⁇ m) of the core
- ⁇ (ns / km) is the group delay time difference between the master channel and the slave channel, and the master channel and the slave of the optical communication system. It is a value satisfying the number C2 when the signal arrival time difference s ( ⁇ s) when the optical signal is transmitted on the channel and the transmission distance L (km) of the optical signal are taken.
- the optical fiber according to the present invention has an effect of improving manufacturability by forming a low delay core with a general-purpose refractive index distribution structure. Therefore, the present invention can provide an optical fiber with improved manufacturability for MS-CPE.
- the optical fiber according to the present invention is characterized in that the refractive index of the core is lower than that of pure quartz glass.
- the radius a ( ⁇ m) satisfies the number C4
- the minimum group delay time difference ⁇ min (nm / km) satisfies the number C5
- the pure quartz glass of the core It is characterized in that the specific refractive index difference ⁇ F (%) with respect to is satisfied with the number C6.
- the MFD is the mode field diameter ( ⁇ m) of the core.
- the optical fiber according to the present invention has a plurality of cores, and one of the plurality of cores is a multi-core fiber which is a core for the master channel.
- the present invention can provide an optical fiber with improved manufacturability for MS-CPE.
- FIG. 50 is a diagram illustrating an optical communication system 301 that employs an MS-CPE transmission method.
- the optical communication system 301 includes a transmitter 11, a receiver 12, and an optical transmission line 50.
- the optical transmission line 50 includes a single-core optical fiber, a multi-core optical fiber, a tape core wire in which a plurality of optical fiber core wires (single mode) are arranged in parallel, or an optical cable containing a plurality of optical fiber core wires (single mode). Is.
- one of the cores is a Master channel and the other core is a Slave channel.
- one of the optical fiber core wires is a Master channel
- the other optical fiber core wire is a Slave channel.
- an arbitrary wavelength is used as a Master channel, and another wavelength is used as a Slave channel.
- the DSP processing time reaches about 1 ⁇ s.
- the signal between the low delay Master channel and the Slave channel in the receiver is used. It is desirable that the arrival time difference is 1 ⁇ s or more. Therefore, the signal arrival time difference between the Master and the Slave in the receiver is s ( ⁇ s), the low delay Master channel group delay time ⁇ m ( ⁇ s / km), the Slave channel group delay time ⁇ s ( ⁇ s / km), and the transmission system. Assuming that the length (transmission path length) is L (km), the requirement condition of ⁇ m is determined by the equation (10).
- ⁇ is required to be ⁇ 1.0 ns / km or less in a submarine optical communication system of 1000 km or more, and ⁇ is required to be -3.4 ns / km or less in a land relay system of about 300 km or more.
- the optical fiber is the optical transmission line 50 of FIG. 50
- the “core” refers to only one core in the case of a single-core optical fiber, and any one core in the case of a multi-core fiber.
- the SI type is the step index type refractive index distribution structure of FIG. 51.
- FIG. 51 a single-core optical fiber is described, but in the case of a multi-core fiber, each core has a similar refractive index distribution structure.
- FIG. 2 is a diagram for explaining the characteristics (radius a and specific refractive index difference ⁇ ) required for the core of the master channel.
- the core is pure quartz glass and has a step index type (SI type) refractive index distribution.
- the broken line and the alternate long and short dash line are the international standardization standards for long-distance transmission fibers, ITU-T G. It is a boundary line of a structure that realizes a typical bending loss recommended value of 2.0 dB / 100 tuns or less in 654 and an MFD of 9.5 ⁇ m or more.
- the structure of the gray area surrounded by these curves has optical characteristics suitable for long-distance transmission lines and enables ⁇ ⁇ -1.0 ns / km for general-purpose cut-off shift fibers.
- the slave channel is an SI type optical fiber
- the slave channel may be other than the SI type optical fiber.
- the core structure in which ⁇ b is 2.0 dB / 100 turns is The structure with MFD of 9.5 ⁇ m is The structure in which the group delay time difference ⁇ is -1.0 ns / km is It is represented by.
- FIG. 3 is a diagram illustrating the ⁇ dependence on the design range of the core radius of the master channel.
- K 0 uses ⁇ in the range of -2ns / km ⁇ ⁇ -1.0ns / km. It is represented by.
- K 1 uses ⁇ in the range of -2ns / km ⁇ ⁇ -1.0ns / km. It is represented by.
- K 2 uses ⁇ in the range of -2ns / km ⁇ ⁇ -1.0ns / km. It is represented by.
- the SI type pure quartz core fiber satisfying the above conditions has optical characteristics suitable for a long-distance transmission line, and is -2.0 ns / km or more and -1 with respect to a slave channel corresponding to a general-purpose cutoff shift fiber. It is possible to realize ⁇ of 0.0 ns / km or less. Therefore, the SI type pure quartz core fiber satisfying the number 19 and the number 20 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the "SI type pure quartz core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- "SI type pure quartz core fiber” means a core used for a master channel
- "cutoff shift fiber” means a core used for a slave channel. do.
- the optical fiber is the optical transmission line 50 of FIG. 50
- the “core” refers to only one core in the case of a single-core optical fiber, and any one core in the case of a multi-core fiber.
- the W-type optical fiber is an optical fiber having a refractive index distribution structure shown in FIG. 52.
- FIG. 52 a single-core optical fiber is described, but in the case of a multi-core fiber, each core has a similar refractive index distribution structure.
- an optical fiber having a W-type refractive index distribution having a low refractive index region around the core is often used.
- MS-CPE MS-CPE
- the structure in which ⁇ b is 2.0 dB / 100 tuns or less is a structure in which a 1 is larger than the broken line in the figure, and the structure in which ⁇ is 1.0 ns / km or more is a structure in which a 1 is smaller than the solid line in the figure. Therefore, the structure in which ⁇ b is 2.0 dB / 100 tuns or less and ⁇ is 1.0 ns / km or more is a gray area in the figure. Further, for the structure in which ⁇ b of the broken line is 2.0 dB / 100 tuns, ⁇ 2 / ⁇ 1 and a 1 are used. The structure in which ⁇ of the solid line is 1.0 ns / km satisfies the following relationship.
- the solid line is the group delay time difference ⁇ , and the broken line is the bending loss ⁇ b . It can be said that neither of the design areas shown in FIG. 8 has a dependency on a2 / a1.
- FIG. 9 is a diagram illustrating the ⁇ dependence of the designable range of the core radius.
- the MFD is 9.5 ⁇ m
- the core radius designable range is ⁇ 2 / ⁇ 1 which is the largest designable range.
- the designable range of the core radius decreases, and the design range disappears at -2.0 ns / km (becomes 0 ⁇ m).
- FIG. 10 is a diagram illustrating the ⁇ dependence of K3 at ⁇ 2.0 ns / km ⁇ ⁇ 1.0 ns / km when the MFD is 9.5 ⁇ m.
- K 3 is Satisfy the relationship.
- Solving the number 21 for a 1 represents the smallest designable a 1 for ⁇ 2 / ⁇ 1 , substituting the number 24 for the number 23, and solving the number 23 for a 1 for ⁇ 2 / ⁇ 1 .
- the maximum a1 that can be designed is represented.
- a W-type optical fiber having a pure quartz core satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and has a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber. Can be realized. Therefore, for this reason, the W-type pure quartz core fiber satisfying the number 25 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the slave channel is an SI type optical fiber will be described, but the slave channel may be other than the SI type optical fiber.
- the "W-type pure quartz core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "W-type pure quartz core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- MFD 9.8 ⁇ m.
- the structure in which ⁇ b is 2.0 dB / 100 tuns or less is a structure in which a 1 is larger than the broken line in the figure, and the structure in which ⁇ is 1.0 ns / km or more is a structure in which a 1 is smaller than the solid line in the figure. Therefore, the structure in which ⁇ b is 2.0 dB / 100 tuns or less and ⁇ is 1.0 ns / km or more is a gray area in the figure. Further, for the structure in which the broken line ⁇ b is 2.0 dB / 100 tuns, ⁇ 2 / ⁇ 1 and a 1 are used. The structure that satisfies the relationship of and the solid line ⁇ is 1.0 ns / km Meet.
- FIG. 12 is a diagram illustrating the ⁇ dependence of the designable range of the core radius.
- the MFD is 9.8 ⁇ m
- the core radius designable range is ⁇ 2 / ⁇ 1 which is the largest designable range.
- the designable range of the core radius decreases, and the design range disappears at -1.46 ns / km (it becomes 0 ⁇ m).
- FIG. 13 is a diagram illustrating the ⁇ dependence of K4 at ⁇ 1.46 ns / km ⁇ ⁇ 1.0 ns / km when the MFD is 9.8 ⁇ m.
- K 4 is Satisfy the relationship.
- Solving the number 26 for a 1 represents the smallest designable a 1 for ⁇ 2 / ⁇ 1 , substituting the number 29 for the number 28, and solving the number 29 for a 1 for ⁇ 2 / ⁇ 1 .
- the maximum a1 that can be designed is represented.
- a W-type optical fiber having a pure quartz core satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and has a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber. Can be realized. Therefore, for this reason, the W-type pure quartz core fiber satisfying the number 30 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the slave channel is an SI type optical fiber will be described, but the slave channel may be other than the SI type optical fiber.
- the "W-type pure quartz core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "W-type pure quartz core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- MFD 10.0 ⁇ m.
- the structure in which ⁇ b is 2.0 dB / 100 tuns or less is a structure in which a 1 is larger than the broken line in the figure, and the structure in which ⁇ is 1.0 ns / km or more is a structure in which a 1 is smaller than the solid line in the figure. Therefore, the structure in which ⁇ b is 2.0 dB / 100 tuns or less and ⁇ is 1.0 ns / km or more is a gray area in the figure. Further, for the structure in which the broken line ⁇ b is 2.0 dB / 100 tuns, ⁇ 2 / ⁇ 1 and a 1 are used. The structure that satisfies the relationship of and the solid line ⁇ is 1.0 ns / km Meet.
- FIG. 12 is a diagram illustrating the ⁇ dependence of the designable range of the core radius.
- the MFD is 10.0 ⁇ m
- the core radius designable range is ⁇ 2 / ⁇ 1 which is the largest designable range.
- the designable range of the core radius decreases, and the design range disappears at -1.14 ns / km (becomes 0 ⁇ m).
- FIG. 16 is a diagram illustrating the ⁇ dependence of K5 at -1.14 ns / km ⁇ ⁇ 1.0 ns / km when the MFD is 10.0 ⁇ m.
- K 5 is Satisfy the relationship.
- Solving the number 31 for a 1 represents the smallest designable a 1 for ⁇ 2 / ⁇ 1 , substituting the number 34 for the number 33 and solving the number 33 for a 1 for ⁇ 2 / ⁇ 1 .
- the maximum a1 that can be designed is represented.
- a W-type optical fiber having a pure quartz core satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and has a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber. Can be realized. Therefore, for this reason, the W-type pure quartz core fiber satisfying the number 35 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the slave channel is an SI type optical fiber will be described, but the slave channel may be other than the SI type optical fiber.
- the "W-type pure quartz core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "W-type pure quartz core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- FIG. 17 is a diagram illustrating the MFD dependence of K6.
- the dependency is Can be represented by.
- FIG. 19 is a diagram illustrating the MFD dependence of the K 7 .
- the dependency is Can be represented by.
- FIG. 20 is a diagram illustrating the MFD dependence of K8.
- the dependency is Can be represented by.
- a W-type optical fiber having a pure quartz core satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and has a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber. Can be realized. Therefore, for this reason, the W-type pure quartz core fiber satisfying the number 35 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the slave channel is an SI type optical fiber will be described, but the slave channel may be other than the SI type optical fiber.
- the "W-type pure quartz core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "W-type pure quartz core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- the optical communication system of the present embodiment is characterized in that the refractive index of the core of the optical fiber of the optical transmission line 50 is lower than that of pure quartz glass.
- the structural conditions of an optical fiber having a pure quartz glass as a core are described. Fluorinated glass may be used as a core in the SI type and W type structures shown in the first and second embodiments. In this case, a larger ⁇ can be realized by lowering the core refractive index, and the application range of MS-CPE using a low delay signal can be expanded.
- FIG. 21 is a diagram illustrating characteristics (radius a and specific refractive index difference ⁇ F ) required for the core of the master channel.
- the specific refractive index difference ⁇ F is the specific refractive index difference of the fluorinated core with respect to the pure quartz glass.
- the parameters are the group delay time difference ⁇ at a wavelength of 1.55 ⁇ m, the bending loss ⁇ b at a wavelength of 1.625 ⁇ m, the cutoff wavelength ⁇ c, and the Rayleigh scattering loss ⁇ R at a wavelength of 1.55 ⁇ m.
- the difference in the specific refractive index of the clad with respect to the pure quartz glass is adjusted so that the MFD is 9.5 ⁇ m in each structure.
- the one-dot chain line shows 0.17 dB / km, which is equivalent to the Rayleigh scattering loss in a general-purpose SMF.
- Core radius a When satisfied, ⁇ c ⁇ 1.53 ⁇ m and ⁇ b ⁇ 2.0 dB / 100 turns can be realized. Further, ⁇ ⁇ 1.0 ns / km can be realized in the region where ⁇ F is smaller than the solid line, and Rayleigh scattering loss of 0.17 dB / km or less can be realized in the region where ⁇ F is larger than the alternate long and short dash line.
- the solid line is Can be expressed by the formula of.
- the alternate long and short dash line is within the range of the core radius of several 43.
- the structure of the gray region surrounded by the curve shown in FIG. 21 can realize a low delay master channel having optical characteristics suitable for a long-distance transmission line and enabling ⁇ ⁇ 1.0 ns / km.
- FIG. 22 is a diagram illustrating the ⁇ dependency on the design range of ⁇ F of the master channel.
- ⁇ F of the structure is ⁇ F, max , and ⁇ F , max ⁇ F , min are the designable range of ⁇ F depending on ⁇ . As ⁇ decreases, the designable range of ⁇ F decreases, and the design range disappears (becomes 0%) at -14.7 ns / km.
- FIG. 23 is a diagram illustrating the ⁇ dependence of K 9 at ⁇ 14.7 ns / km ⁇ ⁇ 1.0 ns / km when the MFD is 9.5 ⁇ m.
- K 9 is Satisfy the relationship. From the above
- the fluorinated core fiber satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and can realize a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber.
- the SI type fluorinated core fiber satisfying the number 49 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the slave channel is an SI type optical fiber
- the slave channel may be other than the SI type optical fiber.
- the "SI-type fluorinated core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "SI-type fluorinated core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- FIG. 24 is also a diagram illustrating the characteristics (radius a and specific refractive index difference ⁇ F ) required for the core of the master channel.
- the difference in the specific refractive index of the clad with respect to the pure quartz glass is adjusted so that the MFD is 15.0 ⁇ m in each structure.
- the solid line is based on the core radius a in the range of several 50 core radii. Can be expressed by the formula of. Also, the alternate long and short dash line is within the range of the core radius of several 50. Can be expressed by the formula of. That is, In, ⁇ ⁇ -1ns / km and ⁇ R ⁇ 0.17dB / km can be realized.
- the structure of the gray region surrounded by the curve shown in FIG. 24 can realize a low delay master channel having optical characteristics suitable for a long-distance transmission line and enabling ⁇ ⁇ 1.0 ns / km.
- FIG. 25 is a diagram illustrating the ⁇ dependency on the design range of ⁇ F of the master channel.
- FIG. 26 is a diagram illustrating the ⁇ dependence of K 10 at ⁇ 18.0 ns / km ⁇ ⁇ 1.0 ns / km when the MFD is 15.0 ⁇ m.
- K 10 is Satisfy the relationship. From the above
- the fluorinated core fiber satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and can realize a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber.
- the SI type fluorinated core fiber satisfying the number 56 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km.
- the slave channel is an SI type optical fiber
- the slave channel may be other than the SI type optical fiber.
- the "SI-type fluorinated core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "SI-type fluorinated core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- FIG. 27 is a diagram illustrating the MFD dependence of the minimum designable core radius amin in which ⁇ b is 2.0 dB / 100 turns. Amin rises linearly with respect to MFD .
- the solid line in FIG. 27 can be represented by the following equation.
- FIG. 28 is a diagram illustrating the MFD dependence of the minimum designable core radius a max in which ⁇ c is 1.53 ⁇ m or less.
- a max rises linearly with respect to MFD.
- the solid line in FIG. 28 can be expressed by the following equation.
- FIG. 29 is a diagram illustrating the MFD dependence of the designable minimum ⁇ min at ⁇ b of 2.0 dB / 100 turns.
- ⁇ min can be expressed by the following equation.
- Fmax can be expressed by the following equation using the MFD-dependent coefficients K 11 , K 12 , K 13 , K 14 , K 15 , K 16 , core radius a, and group delay time difference ⁇ .
- FIG. 30 is a diagram illustrating the MFD dependence of K 11 .
- the straight line in FIG. 30 can be expressed by the following equation using MFD.
- FIG. 31 is a diagram illustrating the MFD dependence of K 12 .
- the straight line in FIG. 31 can be expressed by the following equation using MFD.
- FIG. 32 is a diagram illustrating the MFD dependence of K 13 .
- the straight line in FIG. 32 can be expressed by the following equation using MFD.
- FIG. 33 is a diagram illustrating the MFD dependence of K 14 .
- the curve of FIG. 33 can be expressed by the following equation using MFD.
- FIG. 34 is a diagram illustrating the MFD dependence of K15 .
- the curve of FIG. 34 can be expressed by the following equation using MFD.
- FIG. 35 is a diagram illustrating the MFD dependence of K 16 .
- the curve of FIG. 35 can be expressed by the following equation using MFD.
- the core radius is in the region of a min ⁇ a ⁇ a max shown by the number 57 and the number 58, and the group delay time difference ⁇ to be designed is the number.
- ⁇ min ⁇ ⁇ -1ns / km using ⁇ min indicated by 59 The fluorinated core fiber satisfying the above relationship has optical characteristics suitable for a long-distance transmission line, and can realize a group delay time reduction of ⁇ or less with respect to a slave channel corresponding to a general-purpose cutoff shift fiber.
- the SI type fluorinated core fiber satisfying the number 68 can realize MS-CPE using a low delay signal in a long-distance transmission line such as a submarine optical communication system exceeding 1000 km. It is also possible to design as a W type by imparting a jacket having a refractive index lower than that in the core region and higher than that in the clad region so as to surround the structure of this embodiment.
- the slave channel is an SI type optical fiber
- the slave channel may be other than the SI type optical fiber.
- the "SI-type fluorinated core fiber” is the optical fiber core used for the master channel
- the “cutoff shift fiber” is the optical fiber core used for the slave channel. Means a line.
- the "SI-type fluorinated core fiber” means a core used for a master channel
- the "cutoff shift fiber” means a core used for a slave channel.
- a fluorine-added core SI optical fiber capable of expanding the application area of MS-CPE using a low delay signal to a land relay system. Since the land relay system is expected to have a transmission line length of about several hundred km, it is desirable that ⁇ from FIG. 1 is -3.4 ns / km or less. Further, it is desirable that ⁇ b is 0.1 dB / 100 turns, which is equivalent to general-purpose SMF.
- FIG. 36 is a diagram illustrating characteristics (radius a and specific refractive index difference ⁇ F ) required for the core of the master channel.
- the parameters are the group delay time difference ⁇ at a wavelength of 1.55 ⁇ m, the bending loss ⁇ b at a wavelength of 1.625 ⁇ m, the cutoff wavelength ⁇ c, and the Rayleigh scattering loss ⁇ R at a wavelength of 1.55 ⁇ m.
- the difference in the specific refractive index of the clad with respect to the pure quartz glass is adjusted so that the MFD is 9.5 ⁇ m in each structure.
- the alternate long and short dash line is represented by the number 45. That is, It is possible to realize ⁇ ⁇ -3.4 ns / km and ⁇ R ⁇ 0.17 dB / km.
- FIG. 37 is a diagram illustrating the ⁇ dependence of the design range of ⁇ F of the master channel.
- FIG. 38 is a diagram illustrating characteristics (radius a and specific refractive index difference ⁇ F ) required for the core of the master channel.
- the difference in the specific refractive index of the clad with respect to the pure quartz glass is adjusted so that the MFD is 15.0 ⁇ m in each structure.
- the alternate long and short dash line can be represented by the number 52 within the range of the core radius of the number 71. That is, It is possible to realize ⁇ ⁇ -3.4 ns / km and ⁇ R ⁇ 0.17 dB / km.
- FIG. 39 is a diagram illustrating the ⁇ dependency on the design range of ⁇ F of the master channel.
- FIG. 40 shows the MFD dependence of the core radius amin in which ⁇ b is 0.1 dB / 100 turns. Amin rises linearly with respect to MFD .
- the solid line in FIG. 40 can be represented by the following equation.
- ⁇ min can be expressed by the following equation.
- the core radius is a min ⁇ a ⁇ a max and the group delay time difference to be designed is ⁇ min ⁇ ⁇ -3.4 ns / km
- ⁇ R becomes 0.17 dB / km ⁇ F min
- ⁇ F max can be expressed by the number 68.
- the structure described in this embodiment can extend the application area of MS-CPE using a low delay signal to about 300 km. It is also possible to design as a W type by imparting a jacket having a refractive index lower than that in the core region and higher than that in the clad region so as to surround the structure of this embodiment.
- FIG. 42 is a diagram illustrating an example of core arrangement of a multi-core optical fiber including a low delay core.
- two or more transmission cores (52, 53) are arranged on a tetragonal grid in the clad 51.
- at least one of the transmission cores (core 52) is a low-delay core having the structure described in the first to fourth embodiments.
- the core 52 is a low-delay master channel
- the other core 53 is a slave channel.
- noise due to disturbance is shared, so that MS-CPE using a low delay channel can be stably operated in the optical communication system 300.
- FIG. 43 is a diagram illustrating an example of core arrangement of a multi-core optical fiber including a low delay core.
- two or more transmission cores (52, 53) are arranged in an annular shape in the clad 51.
- at least one of the transmission cores (core 52) is a low-delay core having the structure described in the first to fourth embodiments.
- the core 52 is a low-delay master channel
- the other core 53 is a slave channel.
- FIG. 44 is a diagram illustrating an example of core arrangement of a multi-core optical fiber including a low delay core.
- two or more transmission cores (52, 53) are arranged in a clad 51 in a hexagonal close-packed structure.
- at least one of the transmission cores (core 52) is a low-delay core having the structure described in the first to fourth embodiments.
- the core 52 is a low-delay master channel
- the other core 53 is a slave channel.
- FIG. 45 is a diagram illustrating an example of core arrangement of a multi-core optical fiber including a low delay core.
- the transmission cores (core 52) described in the first to fourth embodiments are arranged at the center of the clad 51, and two or more transmissions are performed in a square grid pattern around the clad 51 and in the clad 51. It is characterized in that the core 53 is arranged.
- the core 52 is a low-delay master channel
- the other core 53 is a slave channel.
- FIG. 46 is a diagram illustrating an example of core arrangement of a multi-core optical fiber including a low delay core.
- the transmission cores (cores 52) described in the first to fourth embodiments are arranged at the center of the clad 51, and two or more transmission cores 53 are annularly arranged around the clad 51 and in the clad 51. Is characterized by being arranged.
- the core 52 is a low-delay master channel
- the other core 53 is a slave channel.
- FIG. 47 is a diagram illustrating an example of core arrangement of a multi-core optical fiber including a low delay core.
- the transmission cores (cores 52) described in the first to fourth embodiments are arranged at the center of the clad 51, and four transmission cores 53 are arranged around the clad 51 in a square grid pattern. Is characterized by being arranged.
- the core 52 is a low delay master channel
- the core 53 is a slave channel.
- the low-delay master channel is of the SI type
- the slave channel is of the W type having the low refractive index layer 54 on the outer periphery of the core 53.
- the core radius of the low-delay master channel be a m1
- the core radius of the slave channel be as 1
- the radius of the low refractive index layer be as 2.
- the distance between the low delay master channel and the slave channel is defined as ⁇ .
- Each core shares the clad 51, and the difference in the specific refractive index of the clad 51 with respect to the pure quartz glass is ⁇ c . Further, the difference in the specific refractive index of the low refractive index layer 54 with respect to the pure quartz glass is defined as ⁇ d .
- FIG. 48 is a diagram illustrating a design region of the inter-core distance ⁇ and the low refractive index layer refractive index difference ⁇ d for the multi-core optical fiber described with reference to FIG. 47.
- FIG. 48 shows the crosstalk XT m-s between the low delay master channel and the slave channel at a wavelength of 1.625 ⁇ m, the crosstalk XT s-s between the slave channels and the intercore distance ⁇ and ratio of the leakage loss ⁇ c in the slave channel. It is a calculation result of the refractive index difference ⁇ d dependence.
- the solid line shows a structure in which ⁇ c is 0.01 dB / km
- the alternate long and short dash line shows a structure in which XT s-s is -59 dB / km
- the broken line shows a structure in which XT m-s is -59 dB / km. It is known that when both crosstalk XT m-s and XT s-s are -59 dB / km, 10,000 km Quadrature phase shift keying (QPSK) modulation communication can be performed with sufficient transmission quality.
- QPSK Quadrature phase shift keying
- am1 and ⁇ c are 3.4 ⁇ m and ⁇ , respectively. It was set to 0.4%. Further, ass1 is adjusted so that the MFD of the slave channel is 9.5 ⁇ m at a wavelength of 1.55 ⁇ m. a s2 was set to 3as1 based on the existing cutoff shift fiber (W type). In the gray structure in the figure, sufficient transmission quality and sufficient low loss can be achieved in a long-distance transmission line.
- FIG. 49 is a table illustrating an example of the multi-core optical fiber (MCF) structure shown in FIG. 47.
- the group delay time of the low delay master channel is 4.879 ⁇ s / km
- the group delay time of the slave channel is 4.883 ⁇ s / km. This is because the group delay time difference between the low delay master channel and the slave channel is 4 ns / km, and a transmission delay time difference of 1 ⁇ s or more can be realized in an optical transmission line of 250 km or more.
- the present invention is an optical communication system 301 including the optical fiber described in the first to sixth embodiments as an optical transmission line 50. That is, the optical communication system according to the present invention is as follows.
- An MS-CPE transmission type optical communication system including a transmitter, a receiver, and an optical transmission line connecting them, and the optical fiber of the optical transmission line is
- the core having a radius a ( ⁇ m) for the master channel and the clad having a specific refractive index difference ⁇ (%) with respect to the core have a step index (SI) type refractive index distribution structure and satisfy the number C1. It is characterized by that.
- ⁇ (ns / km) is a group delay time difference between the master channel and the slave channel, and is a signal arrival time difference s ( ⁇ s) when an optical signal is transmitted between the master channel and the slave channel of the optical communication system.
- L (km) of the optical signal it is a value satisfying the number C2.
- An MS-CPE transmission type optical communication system including a transmitter, a receiver, and an optical transmission line connecting them, and the optical fiber of the optical transmission line is A core having a radius of a 1 ( ⁇ m) for the master channel, a low refractive index layer surrounding the core and having a specific refractive index difference of ⁇ 1 (%) with respect to the core, and specific refraction with respect to the core.
- the clad having a rate difference of ⁇ 2 (%) has a W-type refractive index distribution structure, and is characterized by satisfying the number C3.
- MFD is the mode field diameter ( ⁇ m) of the core
- ⁇ (ns / km) is the group delay time difference between the master channel and the slave channel, and the master channel and the slave of the optical communication system. It is a value satisfying the number C2 when the signal arrival time difference s ( ⁇ s) when the optical signal is transmitted on the channel and the transmission distance L (km) of the optical signal are taken.
- the optical fiber according to (1) and (2) has a core having a refractive index equivalent to that of pure quartz glass, but the core is fluorine-added glass and has a refractive index higher than that of pure quartz glass. It may be low.
- the optical fiber according to (1) above has a core having a refractive index equivalent to that of pure quartz glass, but the core is fluorinated glass and has a refractive index lower than that of pure quartz glass.
- the radius a ( ⁇ m) satisfies the number C4
- the minimum group delay time difference ⁇ min (nm / km) satisfies the number C5.
- the core is characterized in that the specific refractive index difference ⁇ F (%) with respect to the pure quartz glass satisfies the number C6.
- the MFD is the mode field diameter ( ⁇ m) of the core.
- the optical fiber according to (1) to (4) above has a plurality of cores, and one of the plurality of cores is a core for the master channel.
- the present invention is also the method for designing an optical fiber described in Embodiments 1 to 6. That is, the design method according to the present invention is as follows (see FIG. 53). (6) This is a method for designing an optical fiber provided in an optical communication system of the MS-CPE transmission method.
- the master that satisfies the number C2 when the signal arrival time difference s ( ⁇ s) when an optical signal is transmitted between the master channel and the slave channel of the optical communication system and the transmission distance L (km) of the optical signal are taken.
- SI step index
- Finding the radius a ( ⁇ m) of the core and the specific refractive index difference ⁇ (%) of the clad with respect to the core (step S02). It is characterized by. (7)
- a method for designing an optical fiber included in an optical communication system of the MS-CPE transmission method The master that satisfies the number C2 when the signal arrival time difference s ( ⁇ s) when an optical signal is transmitted between the master channel and the slave channel of the optical communication system and the transmission distance L (km) of the optical signal are taken. Calculate the group delay time difference ⁇ (ns / km) between the channel and the slave channel (step S01), and from the number C3, the radius a of the core for the master channel of the optical fiber having the W-type refractive index distribution structure.
- Step S02 It is characterized by.
- the optical fiber according to (6) and (7) has a core having a refractive index equivalent to that of pure quartz glass, but the core is fluorine-added glass and has a refractive index higher than that of pure quartz glass. It is characterized by being low.
- the optical fiber according to (6) above has a core having a refractive index equivalent to that of pure quartz glass, but the optical fiber is fluorinated glass and the refractive index of the core is higher than that of pure quartz glass. If low, Finding the radius a ( ⁇ m) so as to satisfy the number C4, Determining the minimum group delay time difference ⁇ min (nm / km) to satisfy the number C5, and finding the specific refractive index difference ⁇ F (%) with respect to the pure quartz glass of the core to satisfy the number C6. It is characterized by.
- the optical fiber according to (6) to (9) has a plurality of cores, one of the plurality of cores is a core for the master channel.
- Transmitter 12 Receiver 50: Optical transmission line (optical fiber) 51: Clad 52: Master channel core 53: Slave channel core 54: Low refractive index layer 301: Optical communication system
Abstract
Description
マスターチャネル用の半径a(μm)のコアと、前記コアに対して比屈折率差Δ(%)であるクラッドとがステップインデックス(SI)型の屈折率分布構造であり、且つ数C1を満たすことを特徴とする。
マスターチャネル用の半径a1(μm)のコアと、前記コアの周囲を取り囲み、前記コアに対して比屈折率差Δ1(%)である低屈折率層と、前記コアに対して比屈折率差Δ2(%)であるクラッドとがW型の屈折率分布構造であり、且つ数C3を満たすことを特徴とする。
コアの屈折率を低下することで、より大きなΔτを実現することができ、低遅延信号を用いたMS-CPEの適用領域を拡大することができる。
図50は、MS-CPE伝送方式を採用する光通信システム301を説明する図である。光通信システム301は、送信機11、受信機12及び光伝送路50を備える。光伝送路50は、単一コア光ファイバ、マルチコア光ファイバ、複数の光ファイバ心線(単一モード)を並列させたテープ芯線、又は複数の光ファイバ心線(単一モード)を内包する光ケーブルである。マルチコア光ファイバの場合、いずれかのコアをMasterチャネル、他のコアをSlaveチャネルとする。テープ芯線及び光ケーブルの場合、いずれかの光ファイバ心線をMasterチャネル、他の光ファイバ心線をSlaveチャネルとする。単一コア光ファイバの場合、任意の波長をMasterチャネル、他の波長をSlaveチャネルとする。
本実施形態では、海底光通信システムに適したSI型の屈折率分布構造を持つ光ファイバにおいて、低遅延masterチャネルを実現するコアの設計方法について説明する。ここで、光ファイバとは図50の光伝送路50であり、「コア」とは、単一コア光ファイバであれば1つしかないコアを指し、マルチコアファイバであればいずれか1つのコアを指し、テープ芯線又は光ファイバケーブルであれば内包するいずれかの光ファイバ心線のコアを指す。SI型とは図51のステップインデックス型の屈折率分布構造である。図51では、単一コア光ファイバで説明しているが、マルチコアファイバの場合、各コアについて同様な屈折率分布構造を持つ。
同様に図5よりK1はΔτを用いて-2ns/km<Δτ<-1.0ns/kmの範囲で
さらに同様に図6よりK2はΔτを用いて-2ns/km<Δτ<-1.0ns/kmの範囲で
本実施形態では、海底光通信システムに適したW型の屈折率分布構造を持つ光ファイバにおいて、低遅延masterチャネルを実現するコアの設計方法について説明する。
ここで、光ファイバとは図50の光伝送路50であり、「コア」とは、単一コア光ファイバであれば1つしかないコアを指し、マルチコアファイバであればいずれか1つのコアを指し、テープ芯線又は光ファイバケーブルであれば内包するいずれかの光ファイバ心線のコアを指す。W型光ファイバとは図52に示す屈折率分布構造を持つ光ファイバである。図52では、単一コア光ファイバで説明しているが、マルチコアファイバの場合、各コアについて同様な屈折率分布構造を持つ。
また、図20は、K8のMFD依存性を説明する図である。当該依存性は
本実施形態の光通信システムは、光伝送路50の光ファイバの前記コアの屈折率が純石英ガラスより低いことを特徴とする。
実施形態1および2では、純石英ガラスをコアとする光ファイバの構造条件について記載した。実施形態1および2で示したSI型およびW型構造においてフッ素添加ガラスをコアとしてもよい。この場合、コア屈折率が低下することでより大きなΔτを実現することができ、低遅延信号を用いたMS-CPEの適用領域を拡大することができる。
パラメータは、波長1.55μmにおける群遅延時間差Δτ、波長1.625μmにおける曲げ損失αb、カットオフ波長λc、および波長1.55μmにおけるレイリー散乱損失αRである。ここで各構造においてMFDが9.5μmとなるように純石英ガラスに対するクラッドの比屈折率差を調整している。
図21に記載した曲線で囲まれる灰色の領域の構造は、長距離伝送路に適した光学特性を有し、かつΔτ<-1.0ns/kmを可能とする低遅延masterチャネルを実現できる。
図24に記載した曲線で囲まれる灰色の領域の構造は、長距離伝送路に適した光学特性を有し、かつΔτ<-1.0ns/kmを可能とする低遅延masterチャネルを実現できる。
本実施形態では低遅延信号を用いたMS-CPEを陸上中継システムへ適用領域を拡大可能なフッ素添加コアSI光ファイバについて説明する。陸上中継システムは数100km程度の伝送路長が想定されるため、図1からΔτは-3.4ns/km以下とすることが望ましい。またαbは汎用のSMFと同等の0.1dB/100turnsとすることが望ましい。
パラメータは、波長1.55μmにおける群遅延時間差Δτ、波長1.625μmにおける曲げ損失αb、カットオフ波長λc、および波長1.55μmにおけるレイリー散乱損失αRである。ここで各構造においてMFDが9.5μmとなるように純石英ガラスに対するクラッドの比屈折率差を調整している。
本実施形態では、光伝送路50がマルチコア光ファイバである光通信システムを説明する。本実施形態のマルチコア光ファイバは、実施形態1~4で説明したコア構造を少なくとも一つ以上を含む。
(実施例1)
図42は、低遅延コアを含むマルチコア光ファイバのコア配置例を説明する図である。本実施例のマルチコア光ファイバは、クラッド51の中に正方格子上に2以上の伝送コア(52、53)が配置される。そして、その伝送コアのうち少なくとも一つ(コア52)を実施形態1~4で説明した構造の低遅延コアとすることを特徴とする。本実施例のマルチコア光ファイバではコア52を低遅延masterチャネルとし、他のコア53をslaveチャネルとする。これにより、外乱によるノイズが共通化されるため、光通信システム300において低遅延チャネルを用いたMS-CPEを安定的に動作させることができる。
図43は、低遅延コアを含むマルチコア光ファイバのコア配置例を説明する図である。
本実施例のマルチコア光ファイバは、クラッド51の中に円環状に2以上の伝送コア(52、53)が配置される。そして、その伝送コアのうち少なくとも一つ(コア52)を実施形態1~4で説明した構造の低遅延コアとすることを特徴とする。本実施例のマルチコアファイバではコア52を低遅延masterチャネルとし、他のコア53をslaveチャネルとする。これにより、外乱によるノイズが共通化されるため、光通信システム300において低遅延チャネルを用いたMS-CPEを安定的に動作させることができる。
図44は、低遅延コアを含むマルチコア光ファイバのコア配置例を説明する図である。
本実施例のマルチコア光ファイバは、クラッド51の中に六方最密構造状に2以上の伝送コア(52、53)が配置される。そして、その伝送コアのうち少なくとも一つ(コア52)を実施形態1~4で説明した構造の低遅延コアとすることを特徴とする。本実施例のマルチコアファイバではコア52を低遅延masterチャネルとし、他のコア53をslaveチャネルとする。これにより、外乱によるノイズが共通化されるため、光通信システム300において低遅延チャネルを用いたMS-CPEを安定的に動作させることができる。
図45は、低遅延コアを含むマルチコア光ファイバのコア配置例を説明する図である。
本実施例のマルチコア光ファイバは、クラッド51の中心に、実施形態1~4で説明した伝送コア(コア52)が配置され、その周囲且つクラッド51の中に正方格子状に二つ以上の伝送コア53が配置されていることを特徴とする。本実施例のマルチコアファイバではコア52を低遅延masterチャネルとし、他のコア53をslaveチャネルとする。これにより、外乱によるノイズが共通化されるため、光通信システム300において低遅延チャネルを用いたMS-CPEを安定的に動作させることができる。
図46は、低遅延コアを含むマルチコア光ファイバのコア配置例を説明する図である。
本実施例のマルチコア光ファイバは、クラッド51の中心に、実施形態1~4で説明した伝送コア(コア52)が配置され、その周囲且つクラッド51の中に円環状に2以上の伝送コア53が配置されていることを特徴とする。本実施例のマルチコアファイバではコア52を低遅延masterチャネルとし、他のコア53をslaveチャネルとする。これにより、外乱によるノイズが共通化されるため、光通信システム300において低遅延チャネルを用いたMS-CPEを安定的に動作させることができる。
図47は、低遅延コアを含むマルチコア光ファイバのコア配置例を説明する図である。
本実施例のマルチコア光ファイバは、クラッド51の中心に、実施形態1~4で説明した伝送コア(コア52)が配置され、その周囲且つクラッド51の中に正方格子状に4つの伝送コア53が配置されていることを特徴とする。コア52は低遅延masterチャネル、コア53はslaveチャネルである。ここで低遅延masterチャネルはSI型とし、slaveチャネルはコア53の外周に低屈折率層54を備えるW型とする。低遅延masterチャネルのコア半径をam1とし、slaveチャネルのコア半径をas1、低屈折率層半径をas2とする。また、低遅延masterチャネルとslaveチャネル間距離(コア52とコア53の中心間距離)をΛとする。各コアはクラッド51を共有し、クラッド51の純石英ガラスに対する比屈折率差をΔcとする。また、低屈折率層54の純石英ガラスに対する比屈折率差をΔdとする。
図48は、波長1.625μmにおける低遅延masterチャネルとslaveチャネル間のクロストークXTm-s、slaveチャネル間のクロストークXTs-sおよびslaveチャネルにおける漏洩損失αcのコア間距離Λおよび比屈折率差Δd依存性の計算結果である。
本発明は、実施形態1から6で説明した光ファイバを光伝送路50として備える光通信システム301である。すなわち、本発明に係る光通信システムは次の通りである。
(1)送信機と受信機とこれらを接続する光伝送路を備えるMS-CPE伝送方式の光通信システムであって、前記光伝送路の光ファイバは、
マスターチャネル用の半径a(μm)のコアと、前記コアに対して比屈折率差Δ(%)であるクラッドとがステップインデックス(SI)型の屈折率分布構造であり、且つ数C1を満たすことを特徴とする。
マスターチャネル用の半径a1(μm)のコアと、前記コアの周囲を取り囲み、前記コアに対して比屈折率差Δ1(%)である低屈折率層と、前記コアに対して比屈折率差Δ2(%)であるクラッドとがW型の屈折率分布構造であり、且つ数C3を満たすことを特徴とする。
前記半径a(μm)が数C4を満たし、
最小の前記群遅延時間差Δτmin(nm/km)が数C5を満たし、
前記コアの純石英ガラスに対する比屈折率差ΔF(%)が数C6を満たすことを特徴とする。
(6)MS-CPE伝送方式の光通信システムが備える光ファイバの設計方法であって、
前記光通信システムの前記マスターチャネルと前記スレーブチャネルで光信号を伝送したときの信号到達時間差s(μs)、及び前記光信号の伝送距離L(km)としたとき、数C2を満たす、前記マスターチャネルとスレーブチャネルとの群遅延時間差Δτ(ns/km)を算出すること(ステップS01)、及び
数C1より、ステップインデックス(SI)型の屈折率分布構造の前記光ファイバの、マスターチャネル用のコアの半径a(μm)と、クラッドの前記コアに対する比屈折率差Δ(%)とを見出すこと(ステップS02)、
を特徴とする。
(7)MS-CPE伝送方式の光通信システムが備える光ファイバの設計方法であって、
前記光通信システムの前記マスターチャネルと前記スレーブチャネルで光信号を伝送したときの信号到達時間差s(μs)、及び前記光信号の伝送距離L(km)としたとき、数C2を満たす、前記マスターチャネルとスレーブチャネルとの群遅延時間差Δτ(ns/km)を算出すること(ステップS01)、及び
数C3より、W型の屈折率分布構造の前記光ファイバの、マスターチャネル用のコアの半径a1(μm)と、前記コアの周囲を取り囲む低屈折率層の前記コアに対する比屈折率差Δ1(%)と、クラッドの前記コアに対する比屈折率差Δ2(%)とを見出すこと(ステップS02)、
を特徴とする。
数C4を満たすように前記半径a(μm)を見出すこと、
数C5を満たすように最小の前記群遅延時間差Δτmin(nm/km)を決定すること、及び
数C6を満たすように前記コアの純石英ガラスに対する比屈折率差ΔF(%)を見出すこと
を特徴とする。
12:受信機
50:光伝送路(光ファイバ)
51:クラッド
52:マスターチャネル用コア
53:スレーブチャネル用コア
54:低屈折率層
301:光通信システム
Claims (5)
- MS-CPE伝送方式の光通信システムが備える光ファイバであって、
マスターチャネル用の半径a1(μm)のコアと、前記コアの周囲を取り囲み、前記コアに対して比屈折率差Δ1(%)である低屈折率層と、前記コアに対して比屈折率差Δ2(%)であるクラッドとがW型の屈折率分布構造であり、且つ数C3を満たすことを特徴とする光ファイバ。
- 前記コアの屈折率が純石英ガラスより低いことを特徴とする請求項1又は2に記載の光ファイバ。
- 複数のコアを有しており、
前記複数のコアの1つが前記マスターチャネル用のコアであることを特徴とする請求項1から4のいずれかに記載の光ファイバ。
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Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1039155A (ja) * | 1996-04-15 | 1998-02-13 | Sumitomo Electric Ind Ltd | 分散補償ファイバ及びそれを含む光伝送システム |
JP2007504080A (ja) * | 2003-08-29 | 2007-03-01 | コーニング インコーポレイテッド | アルカリ金属酸化物を含有する光ファイバおよびその製造方法と装置 |
JP2017526601A (ja) * | 2014-07-10 | 2017-09-14 | コーニング インコーポレイテッド | 高塩素含有量の低減衰光ファイバー |
WO2018159146A1 (ja) * | 2017-03-03 | 2018-09-07 | 住友電気工業株式会社 | 光ファイバ |
WO2019009284A1 (ja) * | 2017-07-03 | 2019-01-10 | 日本電信電話株式会社 | 光ファイバ及び光伝送システム |
US20190049660A1 (en) * | 2017-08-08 | 2019-02-14 | Corning Incorporated | Low bend loss optical fiber with a chlorine doped core and offset trench |
WO2020162406A1 (ja) * | 2019-02-05 | 2020-08-13 | 古河電気工業株式会社 | 光ファイバ |
-
2021
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- 2021-01-05 CN CN202180085812.9A patent/CN116710822A/zh active Pending
- 2021-01-05 JP JP2022573813A patent/JPWO2022149182A1/ja active Pending
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1039155A (ja) * | 1996-04-15 | 1998-02-13 | Sumitomo Electric Ind Ltd | 分散補償ファイバ及びそれを含む光伝送システム |
JP2007504080A (ja) * | 2003-08-29 | 2007-03-01 | コーニング インコーポレイテッド | アルカリ金属酸化物を含有する光ファイバおよびその製造方法と装置 |
JP2017526601A (ja) * | 2014-07-10 | 2017-09-14 | コーニング インコーポレイテッド | 高塩素含有量の低減衰光ファイバー |
WO2018159146A1 (ja) * | 2017-03-03 | 2018-09-07 | 住友電気工業株式会社 | 光ファイバ |
WO2019009284A1 (ja) * | 2017-07-03 | 2019-01-10 | 日本電信電話株式会社 | 光ファイバ及び光伝送システム |
US20190049660A1 (en) * | 2017-08-08 | 2019-02-14 | Corning Incorporated | Low bend loss optical fiber with a chlorine doped core and offset trench |
WO2020162406A1 (ja) * | 2019-02-05 | 2020-08-13 | 古河電気工業株式会社 | 光ファイバ |
Non-Patent Citations (6)
Title |
---|
FEUER, M. D. ET AL.: "Joint Digital Signal Processing Receivers for Spatial Superchannels", IEEE PHOTONICS TECHNOLOGY LETTERS, vol. 24, no. 21, 19 October 2012 (2012-10-19), pages 1957 - 1960, XP011488492, DOI: 10.1109/LPT.2012.2220672 * |
SAGAE, Y. ET AL.: "MULTI-FUNCTIONAL MULTI-CORE FIBRE BASED LONG-HAUL TRANSMISSION SYSTEM WITH LOWER DSP COMPLEXITY", 45TH EUROPEAN CONFERENCE ON OPTICAL COMMUNICATION 2019, 22 September 2019 (2019-09-22), pages 1 - 4, XP055958122 * |
V. BOBROVSS. SPOLITISG. IVANOVS: "Latency causes and reduction in optical metro networks", PROCEEDINGS IN SPIE, vol. 9009, 2014, pages 90080C |
VJACESLAVS, B ET AL.: "Latency causes and reduction in optical metro networks", PROCEEDINGS OF SPIE, OPTICAL METRO NETWORKS AND SHORT-HAUL SYSTEMS VI, vol. 9008, 1 February 2014 (2014-02-01), pages 1 - 11, XP060035382 * |
Y. SAGAET. MATSUIT. SAKAMOTOK. NAKAJIMA: "Multi-functional multi-core fibre based long-haul transmission system with lower DSP complexity", ECOC, 2019, pages 1 - 4 |
ZHOU, S. L. WOODWARDR. ISAACB. ZHUT. F. TAUNAYM. FISHTEYNJ. M. FINIM. F. YAN: "Joint Digital Signal Processing Receivers for Spatial Superchannels", PHOTON. |
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