System optimization of pulse shaping filters in fiber optic networks

Patent metadata

Field	Value
Publication number	US-9628189-B2
Application number	US-201514745998-A
Country	US
Kind code	B2
Filing date	Jun 22, 2015
Priority date	Mar 20, 2015
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Optimization systems and methods are described configured to optimize filter coefficients in pulse shaping filters in transmitters and matched filters in receivers to maximize Q-factor in a fiber optic system. The systems and methods include receiving a measured Q-factor for one or more channels; iteratively adjusting filter coefficients of the pulse shaping filters and the matched filters to maximize a measured Q-factor of a channel of the one or more channels; and setting the filter coefficients of the pulse shaping filters and the matched filters to optimized values based on the iteratively adjusting.

First claim

What is claimed is:

1. An optimization method configured to optimize filter coefficients in pulse shaping filters in transmitters and matched filters in receivers to maximize a Q-factor of a channel of one or more channels in a fiber optic system, the optimization method comprises:
iteratively adjusting, via an optimization engine, filter coefficients of the pulse shaping filters at the transmitters and the matched filters at the receivers to maximize a measured Q-factor of the channel, wherein the optimization engine is in communication with the transmitters and the receivers to concurrently adjust the filter coefficients; and
setting the filter coefficients of the pulse shaping filters and the matched filters to optimized values based on the iteratively adjusting.

2. The optimization method of claim 1 , wherein the iteratively adjusting is performed while the fiber optic system is in-service.

3. The optimization method of claim 1 , wherein the iteratively adjusting comprises:
determining updated values for the filter coefficients;
causing update of the filter coefficients to the updated values;
receiving an updated measured Q-factor for the one or more channels based on the updated filter coefficients; and
continuing the determining, the causing, and the receiving the updated measured Q until the filter coefficients are determined to represent the optimized values.

4. The optimization method of claim 3 , wherein the optimized values are determined when one of Kuhn-Tucker conditions are met and a maximum number of iterations is reached.

5. The optimization method of claim 1 , wherein the iteratively adjusting utilizes an objective function defined as maximize[min[Q 1 Q 2 . . . Q N ]] wherein Q n is the measured Q-factor for channel n, and N is a number of channels.

6. The optimization method of claim 1 , wherein the iteratively adjusting utilizes a Sequential Quadratic Programming (SQP) algorithm.

7. The optimization method of claim 1 , wherein the one or more channels comprise at least two channels with super-Nyquist channel spacing between them.

8. An apparatus configured to optimize filter coefficients in pulse shaping filters in transmitters and matched filters in receivers to maximize a Q-factor of a channel of one or more channels in a fiber optic system, the apparatus comprises:
a processor; and
memory storing instructions that, when executed, cause the processor to implement an optimization engine configured to
iteratively adjust filter coefficients of the pulse shaping filters at the transmitters and the matched filters at the receivers to maximize a measured Q-factor of the channel, wherein the optimization engine is in communication with the transmitters and the receivers to concurrently adjust the filter coefficients, and
cause setting of the filter coefficients of the pulse shaping filters and the matched filters to optimized values based on the adjustment.

9. The apparatus of claim 8 , wherein the filter coefficients are adjusted while the fiber optic system is in-service.

10. The apparatus of claim 8 , wherein the iteratively adjust comprises the memory storing instructions that, when executed, further cause the processor to
determine updated values for the filter coefficients,
cause update of the filter coefficients to the updated values,
receive an updated measured Q-factor for the one or more channels based on the updated filter coefficients, and
continue the determine, the cause, and the receive the updated measured Q until the filter coefficients are determined to represent the optimized values.

11. The apparatus of claim 10 , wherein the optimized values are determined when one of Kuhn-Tucker conditions are met and a maximum number of iterations is reached.

12. The apparatus of claim 8 , wherein the apparatus utilizes an objective function defined as maximize[min[Q 1 Q 2 . . . Q N ]] wherein Q n is the measured Q-factor for channel n, and N is a number of channels.

13. The apparatus of claim 8 , wherein the apparatus utilizes a Sequential Quadratic Programming (SQP) algorithm.

14. The apparatus of claim 8 , wherein the one or more channels comprise at least two channels with super-Nyquist channel spacing between them.

15. A fiber optic system, comprising:
one or more transmitters each comprising a pulse shaping filter;
one or more receivers each configured to communicate with a respective transmitter of the one or more receivers and each comprising a matched filter; and
an optimization engine in communication with the one or more transmitters and the one or more receivers, wherein the optimization engine is configured to
iteratively adjust filter coefficients of the pulse shaping filters at the transmitters and the matched filters at the receivers to maximize a measured Q-factor of a channel of one or more channels, wherein the optimization engine concurrently adjusts the filter coefficients at the transmitters and the receivers, and
cause setting of the filter coefficients of the pulse shaping filters and the matched filters to optimized values based on the iterative adjustment.

16. The fiber optic system of claim 15 , wherein the filter coefficients are adjusted while the fiber optic system is in-service.

17. The fiber optic system of claim 15 , wherein, to perform the iteratively adjust, the optimization engine is configured to
determine updated values for the filter coefficients,
cause update of the filter coefficients to the updated values,
receive an updated measured Q-factor for the one or more channels based on the updated filter coefficients, and
continue the determine, the cause, and the receive the updated measured Q until the filter coefficients are determined to represent the optimized values.

18. The fiber optic system of claim 17 , wherein the optimized values are determined when one of Kuhn-Tucker conditions are met and a maximum number of iterations is reached.

19. The fiber optic system of claim 15 , wherein the optimization engine utilizes an objective function defined as maximize[min[Q 1 Q 2 . . . Q N ]] wherein Q n is the measured Q-factor for channel n, and N is a number of channels.

20. The fiber optic system of claim 15 , wherein the one or more channels comprise at least two channels with super-Nyquist channel spacing between them.

Assignees

• Ciena Corp

Inventors

• CHÂTELAIN BENOîT
• Mehta Priyanth

Classifications

• H04B10/07953

  Monitoring or measuring OSNR, BER or Q · CPC title

• H04L25/0384 Primary

  Design of pulse shapes (pulse shape for impulse radio H04B1/7172) · CPC title

• H04B10/25073

  using spectral equalisation, e.g. spectral filtering · CPC title

• H04B10/508 Primary

  Pulse generation, e.g. generation of solitons · CPC title

• H04B10/0799

  Monitoring line transmitter or line receiver equipment · CPC title