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US 2004/0105638 A1Published application
Chromatic dispersion compensation module
AssigneeAlcatel
InventorsPierre Sillard, Bruno Dany, Alain Bertaina, Maxime Gorlier
Life of this patent
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Abstract
The field of the invention is that of chromatic dispersion compensation modules and of methods of designing chromatic dispersion compensation modules. The design method includes an optimization step consisting in reducing an original quality criterion. The compensation optical fiber of the module has a chromatic dispersion less than a first threshold and chromatic dispersion sufficiently negative for the quality criterion to be less than a second threshold.
Claims28
A chromatic dispersion compensation module comprising,
- an enclosure (49) including an input terminal (41) and an output terminal (42),
- a higher-order mode chromatic dispersion compensation optical line (40) situated inside the enclosure and disposed between the input terminal and the output terminal, the line comprising one or more HOM multimode chromatic dispersion compensation optical fibers (43, 45) in series and not comprising any single-mode optical fiber,
- an input mode converter (46) for converting the fundamental mode into said higher order mode, situated between the input terminal and the compensation optical line,
- an output mode converter (47) for converting said higher order mode into the fundamental mode, situated between the compensation optical line and the output terminal,
- the module being adapted to be inserted by means of the input and output terminals into a transmission line comprising a standard single-mode line optical fiber adapted to transmit information in a spectral domain of use,
- the input terminal and the input mode converter together introducing into the transmission line an input loss Γin expressed in dB,
- the output terminal and the output mode converter together introducing into the transmission line an output loss Γout expressed in dB,
- additional connections, if any, between compensation optical fibers together introducing into the transmission line a connection loss Γinter expressed in dB,
- the compensation optical fiber or the set of compensation optical fibers in series presenting, at a wavelength of 1550 nm, a plurality of average parameters including an average coefficient of attenuation αDCF expressed in dB/km, an average chromatic dispersion DDCF expressed in ps/nm-km and that is negative, an average dispersion slope SDCF expressed in ps/nm2-km and that is negative, an average chromatic dispersion to dispersion slope ratio DDCF/SDCF expressed in nm, an average figure of merit FOMDCF defined as −DDCF/αDCF expressed in ps/nm-dB, an average effective area Aeff expressed in μm2, and an average second order coefficient n2 of the refractive index as a function of the intensity expressed in 10−20 m2/W,
- the average chromatic dispersion to dispersion slope ratio being the ratio between the average chromatic dispersion and the average dispersion slope,
- the average figure of merit being the negative of the ratio between the average chromatic dispersion and the average coefficient of attenuation,
- the average coefficient of attenuation in the case of a single compensation optical fiber being lumped with the corresponding coefficient of attenuation of said single compensation optical fiber and in the case of a set of compensation optical fibers in series, the average coefficient of attenuation is equal to the sum of the corresponding attenuation coefficients of the various compensation optical fibers weighted by their respective contributions to the total series length of the compensation optical fibers plus the ratio of the connection loss divided by said total length,
- each of said other average parameters in the case of a single compensation optical fiber being lumped with the corresponding parameter of said single compensation optical fiber and each of said other average parameters in the case of a set of compensation optical fibers in series being the arithmetic mean of the corresponding parameters of the various compensation optical fibers when weighted by the respective lengths of said various compensation optical fibers,
- the module having insertion losses IL expressed in dB,
- where
- 10 IL = D DCM D DCF · α DCF + Γ i n + Γ out
- and where DDCM=−1360 ps/nm,
- the module having a non-linearity criterion NLC representing the effects of the non-linear phase and expressed in 10−6 km/W-dB,
- where
- 11 NLC = 100 · n 2 · ( 1 - 10 D DCM 10 · FOM DCF ) A eff · α DCF · 10 Γ in 10 ,
- the module presenting a quality criterion CQ expressed in dB,
- where CQ=IL+10 log NLC,
- and the compensation optical fiber or the set of compensation optical fibers in series having,
- firstly, an average chromatic dispersion more negative than −200 ps/nm-km,
- secondly, an average chromatic dispersion to dispersion slope ratio in the range 240 nm to 400 nm, and
- thirdly, an average chromatic dispersion sufficiently negative for the quality criterion to be less than 9.5 dB.
23 more elements
A module according to claim 5, characterized in that at least one of the compensation optical fibers of the compensation optical line has a core with at least four core segments, to which core cladding is added.
A chromatic dispersion compensation module comprising,
- an enclosure (49) including an input terminal (41) and an output terminal (42),
- a higher-order mode chromatic dispersion compensation optical line (40) situated inside the enclosure and disposed between the input terminal and the output terminal, the line comprising one or more HOM multimode chromatic dispersion compensation optical fibers (43, 45) in series and not comprising any single-mode optical fiber,
- an input mode converter (46) for converting the fundamental mode into said higher order mode, situated between the input terminal and the compensation optical line,
- an output mode converter (47) for converting said higher order mode into the fundamental mode, situated between the compensation optical line and the output terminal,
- the module being adapted to be inserted by means of the input and output terminals into a transmission line comprising a standard single-mode line optical fiber adapted to transmit information in a spectral domain of use,
- and the compensation optical fiber or at least one of the compensation optical fibers in series having a core having at least five core segments, to which core cladding is added, so that said optical fiber having a core with at least five core segments simultaneously has, at a wavelength of 1550 nm, chromatic dispersion more negative than −300 ps/nm-km and a chromatic dispersion to dispersion slope ratio greater than 200 nm.
3 more elements
A chromatic dispersion compensation module comprising,
- an enclosure (49) including an input terminal (41) and an output terminal (42),
- a higher-order mode chromatic dispersion compensation optical line (40) situated inside the enclosure and disposed between the input terminal and the output terminal, the line comprising one or more HOM multimode chromatic dispersion compensation optical fibers (43, 45) in series and not comprising any single-mode optical fiber,
- an input mode converter (46) for converting the fundamental mode into said higher order mode, situated between the input terminal and the compensation optical line,
- an output mode converter (47) for converting said higher order mode into the fundamental mode, situated between the compensation optical line and the output terminal,
- the module being adapted to be inserted by means of the input and output terminals into a transmission line comprising a single-mode non-zero (at 1550 nm) dispersion shifted line optical fiber adapted to transmit information in a spectral domain of use,
- the input terminal and the input mode converter together introducing into the transmission line an input loss Γin expressed in dB,
- the output terminal and the output mode converter together introducing into the transmission line an output loss Γout expressed in dB,
- additional connections, if any, between compensation optical fibers together introducing into the transmission line a connection loss Γinter expressed in dB,
- the compensation optical fiber or the set of compensation optical fibers in series presenting, at a wavelength of 1550 nm, a plurality of average parameters including an average coefficient of attenuation αDCF expressed in dB/km, an average chromatic dispersion DDCF expressed in ps/nm-km and that is negative, an average dispersion slope SDCF expressed in ps/nm2-km and that is negative, an average chromatic dispersion to dispersion slope ratio DDCF/SDCF expressed in nm, an average figure of merit FOMDCF defined as −DDCF/αDCF expressed in ps/nm-dB, an average effective area Aeff expressed in μm2, and an average second order coefficient n2 of the refractive index as a function of the intensity expressed in 10−20 m2/W,
- the average chromatic dispersion to dispersion slope ratio being the ratio between the average chromatic dispersion and the average dispersion slope,
- the average figure of merit being the negative of the ratio between the average chromatic dispersion and the average coefficient of attenuation,
- the average coefficient of attenuation in the case of a single compensation optical fiber being lumped with the corresponding coefficient of attenuation of said single compensation optical fiber and in the case of a set of compensation optical fibers in series, the average coefficient of attenuation is equal to the sum of the corresponding attenuation coefficients of the various compensation optical fibers weighted by their respective contributions to the total series length of the compensation optical fibers plus the ratio of the connection loss divided by said total length,
- each of said other average parameters in the case of a single compensation optical fiber being lumped with the corresponding parameter of said single compensation optical fiber and each of said other average parameters in the case of a set of compensation optical fibers in series being the arithmetic mean of the corresponding parameters of the various compensation optical fibers when weighted by the respective lengths of said various compensation optical fibers,
- the module having insertion losses IL expressed in dB,
- where
- 12 IL = D DCM D DCF · α DCF + Γ in + Γ out
- and where DDCM=−680 ps/nm,
- the module having a non-linearity criterion NLC representing the effects of the non-linear phase and expressed in 10−6 km/W-dB,
- where
- 13 NLC = 100 · n 2 · ( 1 - 10 D DCM 10 · FOM DCF ) A eff · α DCF · 10 Γ in 10 ,
- the module having a quality criterion CQ expressed in dB,
- where CQ=IL+10 log NLC,
- and the compensation optical fiber or the set of compensation optical fibers in series presenting,
- firstly, an average chromatic dispersion more negative than −250 ps/nm-km,
- secondly, an average chromatic dispersion sufficiently negative for the quality criterion to be less than 5 dB.
22 more elements
A chromatic dispersion compensation module comprising,
- an enclosure (49) including an input terminal (41) and an output terminal (42),
- a higher-order mode chromatic dispersion compensation optical line (40) situated inside the enclosure and disposed between the input terminal and the output terminal, the line comprising one or more HOM multimode chromatic dispersion compensation optical fibers (43, 45) in series and not comprising any single-mode optical fiber,
- an input mode converter (46) for converting the fundamental mode into said higher order mode, situated between the input terminal and the compensation optical line,
- an output mode converter (47) for converting said higher order mode into the fundamental mode, situated between the compensation optical line and the output terminal,
- the module being adapted to be inserted by means of the input and output terminals into a transmission line comprising a single-mode non-zero (at 1550 nm) dispersion shifted line optical fiber adapted to transmit information in a spectral domain of use,
- and the compensation optical fiber or at least one of the compensation optical fibers in series having a core having at least four core segments, to which core cladding is added, so that said optical fiber having a core with at least four core segments simultaneously has, at a wavelength of 1550 nm, chromatic dispersion more negative than −300 ps/nm-km and a chromatic dispersion to dispersion slope ratio greater than 80 nm.
3 more elements
A method of designing a chromatic dispersion compensation module,
- said module being adapted to comprise,
- an enclosure including an input terminal and an output terminal,
- a higher-order mode chromatic dispersion compensation optical line situated inside the enclosure and disposed between the input terminal and the output terminal, the line comprising one or more HOM multimode chromatic dispersion compensation optical fibers in series and not comprising any single-mode optical fiber,
- an input mode converter for converting the fundamental mode into said higher order mode, situated between the input terminal and the compensation optical line,
- an output mode converter for converting said higher order mode into the fundamental mode, situated between the compensation optical line and the output terminal,
- said module being adapted to be inserted by means of the input and output terminals into a transmission line comprising a single-mode line optical fiber adapted to transmit information in a spectral domain of use,
- the input terminal and the input mode converter together introducing into the transmission line an input loss Γin expressed in dB,
- the output terminal and the output mode converter together introducing into the transmission line an output loss Γout expressed in dB,
- additional connections, if any, between compensation optical fibers together introducing into the transmission line a connection loss Γinter expressed in dB,
- the compensation optical fiber or the set of compensation optical fibers in series presenting, at a wavelength of 1550 nm, a plurality of average parameters including an average coefficient of attenuation αDCF expressed in dB/km, an average chromatic dispersion DDCF expressed in ps/nm-km and that is negative, an average dispersion slope SDCF expressed in ps/nm2-km and that is negative, an average chromatic dispersion to dispersion slope ratio DDCF/SDCF expressed in nm, an average figure of merit FOMDCF defined as −DDCF/αDCF expressed in ps/nm-dB, an average effective area Aeff expressed in μm2, and an average second order coefficient n2 of the refractive index as a function of the intensity expressed in 10−20 m2/W,
- the average chromatic dispersion to dispersion slope ratio being the ratio between the average chromatic dispersion and the average dispersion slope,
- the average figure of merit being the negative of the ratio between the average chromatic dispersion and the average coefficient of attenuation,
- the average coefficient of attenuation in the case of a single compensation optical fiber being lumped with the corresponding coefficient of attenuation of said single compensation optical fiber and in the case of a set of compensation optical fibers in series, the average coefficient of attenuation is equal to the sum of the corresponding attenuation coefficients of the various compensation optical fibers weighted by their respective contributions to the total series length of the compensation optical fibers plus the ratio of the connection loss divided by said total length,
- each of said other average parameters in the case of a single compensation optical fiber being lumped with the corresponding parameter of said single compensation optical fiber and each of said other average parameters in the case of a set of compensation optical fibers in series being the arithmetic mean of the corresponding parameters of the various compensation optical fibers when weighted by the respective lengths of said various compensation optical fibers,
- said module being adapted to present insertion losses IL expressed in dB,
- where
- 14 IL = D DCM D DCF · α DCF + Γ in + Γ out
- and where DDCM represents the negative of the cumulative dispersion of the line optical fiber, said module being adapted to have a non-linearity criterion NLC representing the effects of the non-linear phase and expressed in 10−6 km/W-dB,
- where
- 15 NLC = 100 · n 2 · ( 1 - 10 D DCM 10 · FOM DCF ) A eff · α DCF · 10 Γ in 10 ,
- said module being adapted to present a quality criterion CQ expressed in dB,
- where CQ=IL+10 log NLC,
- said design method including an optimization step for optimizing said module, said optimization step consisting in reducing the quality criterion.
20 more elements
A higher-order mode chromatic dispersion compensation optical fiber having a core having at least four core segments, to which core cladding is added, and simultaneously having, at a wavelength of 1550 nm, chromatic dispersion more negative than −300 ps/nm-km and a chromatic dispersion to dispersion slope ratio greater than 80 nm.
A higher-order mode chromatic dispersion compensation optical fiber having a core having at least five core segments, to which core cladding is added, and simultaneously having, at a wavelength of 1550 nm, chromatic dispersion more negative than −300 ps/nm-km and a chromatic dispersion to dispersion slope ratio greater than 200 nm.
Dependencies are inferred from the claim text.