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US 2012/0057873 A1Published application
Optical communication system having low latency
AssigneeInfinera Corporation
InventorsPAUL R. MORKEL, David F. Welch
Life of this patent
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Abstract
Consistent with the present disclosure, an optical communication system is provided in which client data is input to a first node and output from a second node, spaced from the first node, with little delay. In one example, the delay is reduced by including higher order Raman amplifiers that provide a substantially uniform gain along the length of a fiber optic link, thereby reducing the number of EDFAs that may otherwise be installed along the optical fiber link or eliminating such EDFAs entirely. In another example, FEC encoding and decoding are not employed, thereby reducing the delay even further.
Claims24
An apparatus, comprising:
- a pump laser configured to supply pump light having a pump wavelength to an optical communication path, the pump light imparting a first Raman gain at a first wavelength spectrally spaced from the pump wavelength by a first Stokes shift, such that the first Raman gain imparts a second Raman gain at a second wavelength spectrally spaced from the first wavelength by a second Stokes shift, the second wavelength being a signal wavelength;
- a first node that receives a first client signal at a time t1, the first client signal carrying client data, the first node being coupled to a first end of the optical communication path and supplying an optical signal at the signal wavelength in response to the client signal;
- a second node configured to supply a second client signal at time t2 in response to the optical signal, the second client signal carrying the client data, a system propagation delay being a difference between t2 and t1, the second node being coupled to a second end of the optical communication path, the optical communication path including a plurality of consecutively arranged segments of optical transmission fiber extending from the first node to the second node, a fiber propagation delay being a time period during which the optical signal propagates through the plurality of segments of optical fiber over a distance (D) extending from the first node to the second node,
- wherein a difference between the system propagation delay and the fiber propagation delay is an equipment propagation delay (Edelay) that satisfies:
- Edelay≦D*1.7nsec/km
- where D is units of kilometers.
3 more elements
An apparatus, comprising:
- a pump laser configured to supply pump light having a pump wavelength to an optical communication path, the pump light imparting a first Raman gain at a first wavelength spectrally spaced from the pump wavelength by a first Stokes shift, such that the first Raman gain imparts a second Raman gain at a second wavelength spectrally spaced from the first wavelength by a second Stokes shift, and the second Raman gain imparts a third Raman gain at a third wavelength spectrally spaced from the second wavelength by a third Stokes shift, the third wavelength being a signal wavelength;
- a first node received a first client signal at a time t1, the first client signal carrying client data, the first node being coupled to a first end of the optical communication path and supplying an optical signal at the signal wavelength in response to the client signal;
- a second node configured to supply a second client signal at time t2 in response to the optical signal, the second client signal carrying the client data, a system propagation delay being a difference between t2 and t1, the second node being coupled to a second end of the optical communication path, the optical communication path including a plurality of consecutively arranged segments of optical transmission fiber extending from the first node to the second node, a fiber propagation delay being a time period during which the optical signal propagates through the plurality of segments of optical fiber over a distance (D) extending from the first node to the second node,
- wherein a difference between the system propagation delay and the fiber propagation delay is an equipment propagation delay (Edelay) that satisfies:
- Edelay≦D*1.7nsec/km
- where D is units in kilometers.
3 more elements
An apparatus, comprising:
- a pump laser configured to supply a pump light to an optical communication path, the pump light imparting each of a plurality of Raman gains at a corresponding one of a plurality of wavelengths, each of the plurality of wavelengths being spectrally separated from one another by a corresponding one of a plurality of Stokes shifts, one of the plurality of wavelengths being a signal wavelength;
- a first node having an input that receives a first client signal at a time t1, the first client signal carrying client data, the first node being coupled to a first end of the optical communication path and supplying an optical signal at the signal wavelength in response to the client signal;
- a second node configured to supply a second client signal at time t2 in response to the optical signal, the second client signal carrying the client data, a system propagation delay being a difference between t2 and t1, the second node being coupled to a second end of the optical communication path, the optical communication path including a plurality of consecutively arranged segments of optical transmission fiber extending from the first node to the second node, a fiber propagation delay being a time period during which the optical signal propagates through the plurality of segments of optical fiber over a distance (D) extending from the first node to the second node,
- wherein a difference between the system propagation delay and the fiber propagation delay is an equipment propagation delay (Edelay) that satisfies:
- Edelay≦D*1.7nsec/km
- where D is in units of kilometers.
3 more elements
Dependencies are inferred from the claim text.