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US 6,556,742 B2Granted
Optical wavelength division multiplexed system using wavelength splitters
AssigneeFujitsu Limited
InventorMasataka Shirasaki
Life of this patent
Estimating the term…
Abstract
An optical wavelength division multiplexed system uses wavelength splitters to split channels included in input light into different paths within the system. Odd-numbered channels are split into one path, and even-numbered channels are split into another path, providing increased isolation between channels. Using filters, the system then drops one or more of the isolated, split channels into paths referred to as dropped paths and allows the remaining channels to continue through the filters into output paths. The dropped paths are then combined into one, common dropped path, and the output paths are also combined into one, common output path.
Claims48
An optical wavelength division multiplexed system comprising:
- a splitter splitting input light into a first path and a second path, the first path including even-numbered channels and the second path including odd-numbered channels, the first path comprising a first tunable optical filter and said second path comprising a second tunable optical filter, said first tunable optical filter dropping at least one of the even-numbered channels into a first dropped path comprising a third tunable optical filter and said second tunable optical filter dropping at least one of the odd-numbered channels into a second dropped path comprising a fourth tunable optical filter, wherein the first tunable optical filter and the third tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, and wherein the second tunable optical filter and the fourth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other.
An optical wavelength division multiplexed system comprising:
- a splitter splitting input light into a first path including first channels with channel numbers of multiples of 3, a second path including second channels with channel numbers of multiples of 3 plus 1, and a third path including third channels with channel numbers of multiples of 3 plus 2, the first path including a first tunable optical filter dropping at least one of the first channels into a first dropped path including a fourth tunable optical filter, the second path including a second tunable optical filter dropping at least one of the second channels into a second dropped path including a fifth tunable optical filter, and the third channel including a third tunable optical filter dropping at least one of the third channels into a third dropped path including a sixth tunable optical filter, wherein the first tunable optical filter and the fourth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein the second tunable optical filter and the fifth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, and wherein the third tunable optical filter and the sixth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other.
An optical wavelength division multiplexed system comprising:
- splitters splitting input light into a first path including first channels with channel numbers of multiples of 4, a second path including second channels with channel numbers of multiples of 4 plus 1, a third path including third channels with channel numbers of multiples of 4 plus 2, and a fourth path including fourth channels with channel numbers of multiples of 4 plus 3, the first path including a first tunable optical filter dropping at least one of the first channels into a first dropped path including a fifth tunable optical filter, the second path including a second tunable optical filter dropping at least one of the second channels into a second dropped path including a sixth tunable optical filter, the third path including a third tunable optical filter dropping at least one of the third channels into a third dropped path including a seventh tunable optical filter, and the fourth path including a fourth tunable optical filter dropping at least one of the fourth channels into a fourth dropped path including an eighth tunable optical filter, wherein the first tunable optical filter and the fifth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein the second tunable optical filter and the sixth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein the third tunable optical filter and the seventh tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, and wherein the fourth tunable optical filter and the eighth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other.
An optical wavelength division multiplexed system comprising:
- a splitter splitting input light into a first path and a second path, the first path including even-numbered channels and the second path including odd-numbered channels, the first path comprising a first tunable optical filter and said second path comprising a second tunable optical filter, said first tunable optical filter dropping at least one of the even-numbered channels into a first dropped path comprising a third tunable optical filter and said second tunable optical filter dropping at least one of the odd-numbered channels into a second dropped path comprising a fourth tunable optical filter, wherein the first tunable optical filter and the third tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, and wherein the second tunable optical filter and the fourth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein remaining of the odd-numbered channels and even-numbered channels being recombined and transmitted to an output path.
An optical wavelength division multiplexed system comprising:
- a splitter splitting input light into a first path including first channels with channel numbers of multiples of 3, a second path including second channels with channel numbers of multiples of 3 plus 1, and a third path including third channels with channel numbers of multiples of 3 plus 2, the first path including a first tunable optical filter dropping at least one of the first channels into a first dropped path including a fourth tunable optical filter, the second path including a second tunable optical filter dropping at least one of the second channels into a second dropped path including a fifth tunable optical filter, and the third channel including a third tunable optical filter dropping at least one of the third channels into a third dropped path including a sixth tunable optical filter, wherein the first tunable optical filter and the fourth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein the second tunable optical filter and the fifth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, and wherein the third tunable optical filter and the sixth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein remaining of the channels being recombined and transmitted to an output path.
An optical wavelength division multiplexed system comprising:
- splitters splitting input light into a first path including first channels with channel numbers of multiples of 4, a second path including second channels with channel numbers of multiples of 4 plus 1, a third path including third channels with channel numbers of multiples of 4 plus 2, and a fourth path including fourth channels with channel numbers of multiples of 4 plus 3, the first path including a first tunable optical filter dropping at least one of the first channels into a first dropped path including a fifth tunable optical filter, the second path including a second tunable optical filter dropping at least one of the second channels into a second dropped path including a sixth tunable optical filter, the third path including a third tunable optical filter dropping at least one of the third channels into a third dropped path including a seventh tunable optical filter, and the fourth path including a fourth tunable optical filter dropping at least one of the fourth channels into a fourth dropped path including an eighth tunable optical filter, wherein the first tunable optical filter and the fifth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein the second tunable optical filter and the sixth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein the third tunable optical filter and the seventh tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, and wherein the fourth tunable optical filter and the eighth tunable optical filter are coupled directly in cascade with each other and have the same filtering characteristics as each other, wherein remaining of the channels being recombined and transmitted to an output path.
Dependencies are inferred from the claim text.