OPTICAL COMMUNICATION WITH WAVELENGTH-DEPENDENT AMPLITUDE PRE-COMPENSATION

• US 20190312646A1
• Filed: 04/01/2019
• Published: 10/10/2019
• Est. Priority Date: 04/05/2018
• Status: Abandoned Application

• Current Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Earnshaw, Mark Peter
• Application Number:
  US16/371,750
• Publication Number:
  US 20190312646A1
• Time in Patent Office: Days
• CPC Class Codes: H04B 10/25 Arrangements specific to fibre transmission
• CPC Class Codes: H04B 10/503 Laser transmitters
• CPC Class Codes: H04B 10/506 Multiwavelength transmitters
• CPC Class Codes: H04B 10/54 Intensity modulation
• CPC Class Codes: H04B 10/58 Compensation for non-linear transmitter output
• CPC Class Codes: H04B 2210/254 before the transmission line, i.e. pre-compensation
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0221 Power control, e.g. to keep the total optical power constant

Abstract

An apparatus includes an optical source to produce light in a sequence of wavelength-channels, an optical transmission fiber connected to receive said produced light, an optical wavelength-demultiplexer optically coupled to the optical transmission fiber, and an array of optical data modulators. Each of the optical data modulators is optically coupled to receive light of a corresponding one of the wavelength-channels from the optical source via the optical transmission fiber and the optical wavelength-demultiplexer. The optical source is configured to transmit said light to said optical transmission fiber with a wavelength-dependent intensity.

Claims

1. An apparatus, comprising:

an optical source to produce light in a sequence of wavelength-channels;

an optical transmission fiber connected to receive said produced light;

an optical wavelength-demultiplexer optically coupled to the optical transmission fiber;

an array of optical data modulators, each of the optical data modulators being optically coupled to receive light of a corresponding one of the wavelength-channels from the optical source via the optical transmission fiber and the optical wavelength-demultiplexer; and

wherein the optical source is configured to transmit said light to said optical transmission fiber with a wavelength-dependent intensity.

2. The apparatus of claim 1, wherein the wavelength-dependent intensity is largest for one of the wavelength-channels near an edge of a wavelength range for the sequence of wavelength-channels.

3. The apparatus of claim 2, wherein the wavelength-dependent intensity is largest for wavelength-channels near both edges of the wavelength range.

4. The apparatus of claim 1, further comprising an array of optical data receivers;

and

wherein an optical fiber optically couples to the array of optical data receivers via a second optical wavelength-demultiplexer and optically couples to the array of optical data modulators via an optical wavelength-multiplexer.

5. The apparatus of claim 4, wherein the optical fiber coupled to the array of optical data receivers via the second optical wavelength-demultiplexer is the optical transmission fiber.

6. The apparatus of claim 4, wherein the optical source is configured to, at least, partially, pre-compensate for wavelength-dependent optical attenuation between the optical source and the array of optical data receivers.

7. The apparatus of claim 6, wherein the light received at the array of optical data receivers has a substantially flat wavelength-channel-dependent intensity.

8. The apparatus of claim 2, wherein the optical source includes an array of lasers optically connected to inputs of an optical wavelength-multiplexer;

and

wherein each of the lasers is configured to produce light of a different one of the wavelength-channels; and

wherein different ones of the lasers are configured to be driven such that, at an output of the optical wavelength-multiplexer, light of wavelength-channels near outer boundaries of the sequence having a higher intensity than light of wavelength-channels away from the outer boundaries.

9. The apparatus of claim 4, wherein the apparatus is a wavelength division multiplexing, optical communication system communicatively connected to digital data servers inside a data center.

10. The apparatus of claim 8, further comprising an optical amplifier connected to amplify light output light from the array of lasers and to transmit said amplified light to the optical transmission fiber with a wall plug power efficiency of greater than 10 percent.

11. The apparatus of claim 8, further comprising an optical amplifier connected to amplify light output light from the array of lasers and to transmit said amplified light to the optical transmission fiber with a wall plug power efficiency of greater than 20 percent.

12. The apparatus of claim 1, further comprising an optical amplifier located to amplify light output from the optical source and transmit said amplified light to the optical transmission fiber with a wall plug power efficiency of greater than 10 percent.

13. The apparatus of claim 1, further comprising an optical amplifier located to amplify light output from the optical source and transmit said amplified light to the optical transmission fiber with a wall plug power efficiency of greater than 10 percent.

14. The apparatus of claim 1, wherein optical data modulators are configured to transmit data-modulated light to the optical transmission fiber.

15. A method, comprising:

from a multi-wavelength optical source, transmitting to an optical transmission fiber light with a wavelength-dependent intensity to, at least, partially compensate for a wavelength-dependent optical attenuation due to propagation of the light between the multi-wavelength optical source and optical data receivers of an array; and

wherein each of said optical data receivers is connected via the optical transmission fiber to receive some light of a corresponding wavelength-channel of said transmitted light.

16. The method of claim 15, further comprising:

at each one of a plurality of optical data modulators, data modulating light received from the multi-wavelength optical source in a wavelength-channel corresponding to said one of the optical data modulators; and

wherein the optical data modulators of the plurality are connected to receive light from said multi-wavelength optical source via a same optical fiber.

17. The method of claim 15, wherein each of said optical data receivers is connected to receive a portion of the data modulated light from a different corresponding one of the optical modulators;

and

wherein the array of optical modulators is optically coupled to transmit the data modulated light to a same optical fiber.

18. The method of claim 17, further comprising, at the optical source, adjusting a wavelength dependence of the intensity of said transmitted light, at least, in part based on measurements of light intensities at some of the optical data receivers.

19. The method of claim 15, wherein the wavelength-dependent intensity of the transmitted light is largest for one of the wavelength-channels near an edge of an interval including the sequence of wavelength-channels.

20. The method of claim 15, wherein the wavelength-dependent intensity of the transmitted light has maxima in the wavelength-channels near both edges of an interval including the sequence of wavelength-channels.