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US 10,211,920 B1Granted
Latency based chromatic dispersion estimation methods
AssigneeAmazon Technologies, Inc.
InventorsSalman Khaleghi, Emily Abbess, Alaa Adel Mahdi Hayder, Matthew Connolly
Life of this patent
Estimating the term…
Abstract
Optical communication systems include optical time domain reflectometers that are coupled to link fibers to determine link fiber lengths. After length measurement, chromatic dispersion associated with the measured length is estimated. In some examples, the estimated chromatic dispersion is compensated. A single OTDR can be used to assess a pair of link fibers coupling first and second network nodes by injecting a probe pulse at a common end of the link fibers or by routing the probe pulses from a remote end of one link fiber into a remote end of a second fiber.
Claims18
An optical communication system, comprising:
- an optical fiber pair;
- a first network node coupled to the optical fiber pair, comprising:
- a first plurality of optical transceivers, each configured to communicate at a selected wavelength to produce or receive a combined beam for communication via the optical fiber pair,
- an optical transceiver coupled to the optical fiber pair to cause a supervisory optical signal to co-propagate with the combined beam,
- an optical time domain reflectometer (OTDR) coupled to the optical fiber pair so as to deliver a probe pulse to one fiber of the optical fiber pair and produce an estimate of a fiber distance using a returned portion of the probe pulse,
- a node controller coupled to the OTDR and the optical transceiver of the first network node and configured to estimate chromatic dispersion (CD) for the one fiber of the optical fiber pair, and
- a first chromatic dispersion compensator coupled to the one fiber of the optical fiber pair, and configured to provide a CD compensation based on the CD estimated at the first network node;
- and
- a second network node coupled to the optical fiber pair, comprising:
- a second plurality of optical transceivers, each configured to communicate at a selected wavelength to produce a combined beam or receive corresponding wavelength portions of the combined beam from the first network node so as to communicate via the optical fiber pair,
- an optical transceiver coupled to the optical fiber pair to cause a supervisory optical signal to co-propagate with the combined beam,
- an optical time domain reflectometer coupled to the optical fiber pair so as to deliver a probe pulse to one fiber of the optical fiber pair and produce an estimate of a fiber distance associated using a returned portion of the probe pulse,
- a node controller coupled to the OTDR and the optical transceiver of the second network node and configured to estimate chromatic dispersion for the one fiber of the optical fiber pair;
- and
- a second chromatic dispersion compensator coupled to the one fiber of the optical fiber pair, and configured to provide a CD compensation based on the estimated CD at the second network node.
12 more elements
An apparatus, comprising:
- a plurality of optical transceivers, each configured to transmit and receive respective optical signals at respective wavelengths via at least one optical fiber;
- an optical time domain reflectometer (OTDR) coupled to the at least one optical fiber, wherein the OTDR directs a probe pulse to the at least one optical fiber, receives a returned portion of the probe pulse, and determines a fiber length associated with a temporal delay of the returned portion;
- a node controller coupled to the OTDR, wherein the node controller, based on the temporal delay, estimates a chromatic dispersion associated with the determined fiber length;
- and
- an optical chromatic dispersion (CD) compensator coupled to the node controller and configured to establish a CD compensation based on the estimated CD produced by the node controller.
2 more elements
An apparatus, comprising:
- a plurality of optical transceivers, each configured to transmit and receive respective optical signals at respective wavelengths via at least one optical fiber;
- an optical time domain reflectometer (OTDR) coupled to the at least one optical fiber, wherein the OTDR directs a probe pulse to the at least one optical fiber, receives a returned portion of the probe pulse, and determines a fiber length associated with a temporal delay of the returned portion;
- a node controller coupled to the OTDR, wherein the node controller, based on the temporal delay, estimates a chromatic dispersion associated with the determined fiber length;
- and
- a first fiber coupler situated to direct portions of the probe pulse from the first fiber to the second fiber so as to produce returned pulse portions associated with the first fiber and the second fiber.
2 more elements
An apparatus, comprising:
- a plurality of optical transceivers, each configured to transmit and receive respective optical signals at respective wavelengths via at least one optical fiber;
- an optical time domain reflectometer (OTDR) coupled to the at least one optical fiber, wherein the OTDR directs a probe pulse to the at least one optical fiber, receives a returned portion of the probe pulse, and determines a fiber length associated with a temporal delay of the returned portion;
- a node controller coupled to the OTDR, wherein the node controller, based on the temporal delay, estimates a chromatic dispersion associated with the determined fiber length;
- and
- a memory situated to store CD coefficients for a plurality of optical fiber types, wherein the node controller is coupled to the memory to produce the estimate of CD based on a selected stored CD coefficient and a delay associated with the returned pulse portion.
2 more elements
A method, comprising:
- directing at least one probe pulse to at least one link fiber;
- receiving a reflected portion of the at least one probe pulse returned from the at least one link fiber;
- determining a time delay associated with the returned portion of the at least one probe pulse;
- estimating chromatic dispersion of the at least one link fiber based on the time delay;
- and
- adjusting a chromatic dispersion associated with the at least one link fiber, wherein the at least one link fiber includes a first link fiber and a second link fiber coupled to a first network node and a second network node, wherein the adjusting the chromatic dispersion includes applying an optical chromatic dispersion compensation based on the estimated chromatic dispersion and a chromatic dispersion compensation range associated with a digital chromatic dispersion compensator.
3 more elements
Dependencies are inferred from the claim text.