Method and network control device for optimizing performance of a multi-span optical fiber network

Patent metadata

Field	Value
Publication number	US-11489597-B2
Application number	US-202017063224-A
Country	US
Kind code	B2
Filing date	Oct 5, 2020
Priority date	Oct 5, 2020
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

The present invention relates to a method for optimizing performance of a multi-span optical fiber network. Each span has an associated optical transmission fiber connected to an associated optical amplifier. Gain and output power of the associated optical amplifier are respectively controlled independently. An amplifier noise figure respectively depends on the gain of the associated optical amplifier, with each associated optical amplifier further connected to launch optical signals into a remainder of a corresponding optical transmission line. The method includes the steps of for each span, computing the amplifier noise figure and a non-linear noise generated in the span based on information about the span and using the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power, and optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans.

First claim

The invention claimed is:

1. A method for optimizing performance of a multi-span optical fiber network, wherein each span has an associated optical transmission fiber connected to an associated optical amplifier, wherein gain and output power of the associated optical amplifier are respectively controlled independently, and wherein an amplifier noise figure respectively depends on the gain of the associated optical amplifier, wherein each associated optical amplifier is further connected to launch optical signals into a remainder of a corresponding optical transmission line, and wherein the method comprises the steps of:
for each span, computing the amplifier noise figure and a non-linear noise generated in the span based on information about the span and using the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power; and
optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans, wherein:
the step of optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans further comprises the step of:
separately optimizing performance of each span by setting the gain of an amplifier associated with a particular span and the output power of an amplifier associated with a span that is immediately preceding the particular span based on the computed optimum launch power of the particular span, and by setting the gain of the amplifier associated with the particular span based on an optimum gain that is derived from the computed optimum launch power of the particular span.

2. The method according to claim 1 , wherein the information about the span includes a span length, information about the associated transmission fiber, information about an optical amplifier associated with a previous span, a symbol rate of a corresponding transceiver and a frequency spacing between channels transmitted on the previous span.

3. The method according to claim 1 , wherein the step of optimizing performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans further comprises the steps of:
for each span, using the computed optimum launch power to calculate a maximum generalized optical signal-to-noise ratio of the span; and
using the calculated maximum generalized optical signal-to-noise ratios of all spans to optimize the performance of the multi-span optical fiber network.

4. The method according to claim 1 , wherein linear equivalents of the information about the span are used to compute the amplifier noise figure.

5. The method according to claim 1 , wherein the performance of the multi-span optical fiber network is optimized during a planning phase of a network deployment, wherein usual values are chosen for the information about the span, and optionally, wherein in the multi-span optical fiber network pairs of nodes of the network are associated with distinct bands of optical channels used for communication between the pairs of nodes, wherein a maximum generalized optical signal-to-noise ratio is calculated for the central channel based on the computed optimum launch powers of all spans of the central channel, and wherein the maximum generalized optical signal-to-noise ratio of the central channel is used to optimize the performance of the multi-span optical fiber network.

6. The method according to claim 1 , wherein the performance of the multi-span optical fiber network is optimized as part of a network turn-up and commissioning, wherein exact values are chosen for the information about the span, and optionally, wherein in the multi-span optical fiber network pairs of nodes of the network are associated with distinct bands of optical channels used for communication between the pairs of nodes, wherein a maximum generalized optical signal-to-noise ratio is separately calculated for each channel based on the computed optimum launch powers of all spans of the respective channel, wherein a worst generalized optical signal-to-noise ratio is determined from the calculated maximum generalized optical signal-to-noise ratios of the channels, and wherein the worst generalized optical signal-to-noise ratio is used to optimize the performance of the multi-span optical fiber network.

7. A network control device for optimizing performance of a multi-span optical fiber network in which each span has an associated optical transmission fiber connected to an associated optical amplifier, wherein gain and output power of the associated optical amplifier are respectively controlled independently, and wherein an amplifier noise figure respectively depends on the gain of the associated optical amplifier, wherein each associated optical amplifier is further connected to launch optical signals into a remainder of a corresponding optical transmission line, and wherein the network control device comprises a computing means which is configured to, for each span, compute the amplifier noise figure and a non-linear noise generated in the span based on information about the span and use the computed amplifier noise figure and the computed non-linear noise to compute an optimum launch power, and an optimizing means which is configured to optimize performance of the multi-span optical fiber network based on the computed optimum launch powers of all spans, wherein the optimizing means comprises a controlling means which is configured to separately optimize performance of each span by setting the gain of an amplifier associated with a particular span and the output power of an amplifier associated with a span that is immediately preceding the particular span based on the computed optimum launch power of the particular span, and by setting the gain of the amplifier associated with the particular span based on an optimum gain that is derived from the computed optimum launch power of the particular span.

8. The network control device according to claim 7 , wherein the information about the span includes a span length, information about the associated transmission fiber, information about an optical amplifier associated with a previous span, a symbol rate of a corresponding transceiver and a frequency spacing between channels transmitted on the previous span.

9. The network control device according to claim 7 , wherein the optimizing means further comprises a calculating means which is configured to, for each span, use the computed optimum launch power to calculate a maximum generalized optical signal-to-noise ratio of the span, and wherein the optimizing means is configured to use the calculated maximum generalized optical signal-to-noise ratios of all spans to optimize the performance of the multi-span optical fiber network.

10. The network control device according to claim 7 , wherein the computing means is configured to use linear equivalents of the information about the span to compute the amplifier noise figure.

11. The network control device according to claim 7 , wherein the network control device is configured to optimize the performance of the multi-span optical fiber network during a planning phase of a network deployment, wherein the network control device further comprises a memory in which usual values for the information about the span are stored, and optionally, wherein in the multi-span optical fiber network pairs of nodes of the network are associated with distinct bands of optical channels used for communication between the pairs of nodes, wherein the network control device is configured to calculate a maximum generalized optical signal-to-noise ratio for the central channel based on the computed optimum launch powers of all spans of the central channe

Assignees

• Adva Optical Networking Se

Inventors

• Tibuleac Sorin
• Searcy Steven
• Burtsev Sergey

Classifications

• H04B10/2972

  Each direction being amplified separately · CPC title

• H04B10/2939

  Network aspects · CPC title

• H04B10/697 Primary

  Arrangements for reducing noise and distortion · CPC title

• H04B10/2916

  using Raman or Brillouin amplifiers · CPC title

• H04B10/2935

  with a cascade of amplifiers · CPC title