Reconfigurable optical add/drop multiplexer and procedure for outputting optical signals from such multiplexer
First Claim
1. An apparatus comprising:
- at least one reconfigurable optical add drop multiplexer (ROADM) configured tooperate in a plurality of modes including a first mode and a second mode, and select either the first mode or the second mode in which to operate,receive, in the first mode, a plurality of wavelengths separated by a first wavelength spacing, and receive, in the second mode, a plurality of wavelengths separated by the first wavelength spacing or a greater wavelength spacing,output, in the first mode, a plurality of wavelengths to a network interface, separated by the first wavelength spacing, and output, in the second mode, a plurality of wavelengths to the network interface, at least a subset of which are separated by the greater wavelength spacing, thereby reducing the efficiency of four wave mixing cross products produced in a four-wave-mixing-cross-product-producing fiber optic cable when the fiber optic cable is connected to the network interface receiving the outputted wavelengths, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives outputted wavelengths separated by the first wavelength spacing.
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Accused Products
Abstract
A reconfigurable optical add drop multiplexer (ROADM) includes local interfaces at which optical signals of different wavelengths are locally input into the ROADM, and a network interface configured to connect the ROADM to a network from which multiplexed optical signals of different wavelengths are transmitted to the network. In a first configuration, the ROADM is configured to transmit from the network interface to the network multiplexed signals of different wavelengths having a first minimum frequency difference. In a second configuration, the ROADM is configured to transmit from the network interface to the network multiplexed signals of different wavelengths having a second minimum frequency difference. The second minimum frequency difference is greater than the first minimum frequency difference. This arrangement reduces the power of four wave mixing cross products produced when optical signals of three wavelengths are multiplexed and transmitted from the ROADM to NZDSF or DSF fiber types.
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Citations
38 Claims
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1. An apparatus comprising:
at least one reconfigurable optical add drop multiplexer (ROADM) configured to operate in a plurality of modes including a first mode and a second mode, and select either the first mode or the second mode in which to operate, receive, in the first mode, a plurality of wavelengths separated by a first wavelength spacing, and receive, in the second mode, a plurality of wavelengths separated by the first wavelength spacing or a greater wavelength spacing, output, in the first mode, a plurality of wavelengths to a network interface, separated by the first wavelength spacing, and output, in the second mode, a plurality of wavelengths to the network interface, at least a subset of which are separated by the greater wavelength spacing, thereby reducing the efficiency of four wave mixing cross products produced in a four-wave-mixing-cross-product-producing fiber optic cable when the fiber optic cable is connected to the network interface receiving the outputted wavelengths, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives outputted wavelengths separated by the first wavelength spacing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An apparatus comprising:
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at least one converter arranged to perform an optical-electrical-optical conversion to at least one wavelength of a multi-wavelength optical signal, and to output a resulting converted wavelength; and a reconfigurable optical add drop multiplexer (ROADM) configured to combine the resulting converted wavelength with at least one further wavelength from the multi-wavelength optical signal, wherein a spacing between the converted wavelength and the at least one further wavelength is greater than a spacing between at least two wavelengths of the multi-wavelength optical signal, thereby reducing the efficiency of four wave mixing cross products produced in a four-wave-mixing-cross-product-producing fiber optic cable when the four-wave-mixing-cross-product-producing fiber optic cable is connected to a network interface of the ROADM receiving wavelengths having the spacing between the converted wavelength and the at least one further wavelength, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives wavelengths from the network interface of the ROADM separated by the spacing between the at least two wavelengths of the multi-wavelength optical signal. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A procedure for controlling signal wavelengths comprising:
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selecting either a first mode or a second mode in which a reconfigurable add drop multiplexer (ROADM) operates; receiving with the ROADM a plurality of wavelengths separated by a first wavelength spacing and outputting from the ROADM a plurality of wavelengths to a network interface separated by the first wavelength spacing, when the first mode is selected; and receiving with the ROADM a plurality of wavelengths separated by the first wavelength spacing or a greater wavelength spacing and outputting from the ROADM a plurality of wavelengths to the network interface, at least a subset of which are separated by the greater wavelength spacing, when the second mode is selected, thereby reducing the efficiency of four wave mixing cross products produced in a four-wave-mixing-cross-product-producing fiber optic cable when the fiber optic cable is connected to the network interface receiving the outputted wavelengths, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives outputted wavelengths separated by the first wavelength spacing.
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22. A procedure for controlling optical signals of different wavelengths, comprising:
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performing an optical-electrical-optical conversion to at least one wavelength of a multi-wavelength optical signal, to output a resulting converted wavelength; and combining the resulting converted wavelength with at least one further wavelength from the multi-wavelength optical signal, wherein a spacing between the converted wavelength and the at least one further wavelength is greater than a spacing between at least two wavelengths of the multi-wavelength optical signal, thereby reducing the efficiency of four wave mixing cross products produced in a four-wave-mixing-cross-product-producing fiber optic cable when the four-wave-mixing-cross-product-producing fiber optic cable receives wavelengths having the spacing between the converted wavelength and the at least one further wavelength, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives wavelengths separated by the spacing between the at least two wavelengths of the multi-wavelength optical signal. - View Dependent Claims (23, 24, 25)
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26. An apparatus comprising:
at least one reconfigurable optical add drop multiplexer (ROADM) configured to receive a plurality of wavelengths separated by a first wavelength spacing or a greater wavelength spacing, and output a plurality of wavelengths, at least a subset of which are separated by the greater wavelength spacing, to a fiber optic cable through a network interface when the received wavelengths are separated by the first wavelength spacing, and output a plurality of wavelengths, at least a subset of which are separated by the greater wavelength spacing, to a fiber optic cable through a network interface when the received wavelengths are separated by the greater wavelength spacing, thereby reducing the efficiency of four wave mixing cross products generated in the fiber optic cable when the fiber optic cable is a four-wave-mixing-cross-product-producing fiber optic cable, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives outputted wavelengths separated by the first wavelength spacing. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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33. An apparatus comprising:
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at least one reconfigurable optical add drop multiplexer (ROADM) configured to receive a plurality of wavelengths separated by a first wavelength spacing; and a first converter configured to convert at least one of the received wavelengths to another wavelength to increase the wavelength spacing of the converted at least one wavelength with respect to another received wavelength, wherein the ROADM is configured to receive the converted at least one wavelength and to output a plurality of wavelengths, including the converted at least one wavelength, separated by a greater wavelength spacing than the first wavelength spacing, to a network interface, thereby reducing the efficiency of four wave mixing cross products produced in a four-wave-mixing-cross-product-producing fiber optic cable when the four-wave-mixing-cross-product-producing fiber optic cable is connected to the network interface and receives from the ROADM outputted wavelengths separated by a greater wavelength than the first wavelength spacing, compared to when the four-wave-mixing-cross-product-producing fiber optic cable receives wavelengths separated by the first wavelength spacing. - View Dependent Claims (34, 35, 36, 37, 38)
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Specification