Transmitter apparatus and method

Patent metadata

Field	Value
Publication number	US-9419719-B2
Application number	US-201414219799-A
Country	US
Kind code	B2
Filing date	Mar 19, 2014
Priority date	Mar 19, 2014
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

An apparatus comprises a digital signal processing module configured to receive a data stream and generate a plurality of digital multiple tones, a plurality of digital-to-analog converters coupled to the digital signal processing module, a plurality of drivers coupled to respective digital-to-analog converters, an electro-optic modulator having inputs coupled to the drivers and outputs coupled to a fiber and a multi-wavelength light source coupled to the electro-optic modulator.

First claim

What is claimed is:

1. An apparatus comprising:
a digital signal processing module configured to receive a data stream and generate a plurality of digital multiple tones ranging from a lowest frequency to a highest frequency, wherein the plurality of digital multiple tones form a frequency sequence pattern between the lowest frequency and the highest frequency;
a plurality of digital-to-analog converters coupled to the digital signal processing module;
a plurality of drivers coupled to respective digital-to-analog converters;
an electro-optic modulator having inputs coupled to the drivers and outputs coupled to a fiber, wherein the electro-optic modulator is configured to receive the plurality of digital multiple tones, copy the digital multiple tones onto a plurality of different wavelengths and generate a plurality of corresponding optical signals on each wavelength, and wherein on each wavelength, the plurality of corresponding optical signals keep the same frequency sequence pattern; and
a multi-wavelength light source coupled to the electro-optic modulator, wherein the multi-wavelength light source is configured to generate the plurality of different wavelengths.

2. The apparatus of claim 1 , wherein:
the digital signal processing module, the digital-to-analog converters, the drivers and the electro-optic modulator are connected in cascade.

3. The apparatus of claim 1 , wherein:
the electro-optic modulator is coupled to an optical source.

4. The apparatus of claim 1 , wherein the digital signal processing module is configured to generate:
a first in-phase signal in a first polarization direction at a first output of the digital signal processing module;
a first quadrature signal in the first polarization direction at a second output of the digital signal processing module;
a second in-phase signal in a second polarization direction at a third output of the digital signal processing module; and
a second quadrature signal in the second polarization direction at a fourth output of the digital signal processing module.

5. The apparatus of claim 4 , wherein:
the first output of the digital signal processing module is coupled to a first input of the electro-optic modulator through a first digital-to-analog converter and a first driver;
the second output of the digital signal processing module is coupled to a second input of the electro-optic modulator through a second digital-to-analog converter and a second driver;
the third output of the digital signal processing module is coupled to a third input of the electro-optic modulator through a third digital-to-analog converter and a third driver; and
the fourth output of the digital signal processing module is coupled to a fourth input of the electro-optic modulator through a fourth digital-to-analog converter and a fourth driver.

6. The apparatus of claim 1 , wherein:
each tone of the digital multiple tones is copied onto a single wavelength division multiplexing channel.

7. A device comprising:
a processor configured to generate N digital multiple tones ranging from a first frequency to a second frequency, wherein:
a frequency gap Δfc is placed between a center frequency of a tone to a center frequency of an adjacent tone; and
the N digital multiple tones form a frequency sequence pattern between the first frequency and the second frequency;

an electro-optic modulator coupled to an optical source, wherein the electro-optic modulator is configured to:
receive the N digital multiple tones; and
copy the N digital multiple tones onto N different wavelengths, wherein the electro-optic modulator is configured to generate N corresponding optical signals on each wavelength, and wherein on each wavelength, the N corresponding optical signals keep the same frequency sequence pattern and the N corresponding optical signals are placed in a symmetrical manner with respect to a center optical signal of the N corresponding optical signals; and

an optical filter coupled to the electro-optic modulator, wherein the optical filter is configured such that:
a single tone is selected at each wavelength division multiplexing channel.

8. The device of claim 7 , wherein:
the processor is a digital signal processor.

9. The device of claim 7 , wherein the processor is configured to generate:
a first in-phase signal in a first polarization direction at a first output of the processor;
a first quadrature signal in the first polarization direction at a second output of the processor;
a second in-phase signal in a second polarization direction at a third output of the processor; and
a second quadrature signal in the second polarization direction at a fourth output of the processor.

10. The device of claim 9 , further comprising:
a first digital-to-analog converter coupled to the first output of the processor;
a second digital-to-analog converter coupled to the second output of the processor;
a third digital-to-analog converter coupled to the third output of the processor; and
a fourth digital-to-analog converter coupled to the fourth output of the processor.

11. The device of claim 10 , further comprising:
a first driver coupled between the first digital-to-analog converter and a first input of the electro-optic modulator;
a second driver coupled between the second digital-to-analog converter and a second input of the electro-optic modulator;
a third driver coupled between the third digital-to-analog converter and a third input of the electro-optic modulator; and
a fourth driver coupled between the fourth digital-to-analog converter and a fourth input of the electro-optic modulator.

12. The device of claim 11 , wherein:
the electro-optic modulator is coupled to a laser source.

13. The device of claim 7 , wherein:
the processor is configured to generate a first tone, a second tone and a third tone; and
the optical source is configured to generate a first wavelength λ 1 with a first frequency f 1 , a second wavelength λ 2 with a second frequency f 2 and a third wavelength λ 3 with a third frequency f 3 .

14. The device of claim 13 , wherein:
the electro-optic modulator and the optical filter are configured such that:
the first tone is selected and copied onto a third wavelength channel, wherein a center frequency of the third wavelength channel is equal to (f 3 -Δfc);
the second tone is selected and copied onto a second wavelength channel, wherein a center frequency of the second wavelength channel is equal to f 2 ; and
the third tone is selected and copied onto a first wavelength channel, wherein a center frequency of the first wavelength channel is equal to (f 1 +Δfc).

15. A method comprising:
providing a data stream fed to a processor;
generating N digital multiple tones based upon the data stream, wherein the N digital multiple tones are in a range from a first frequency to a second frequency and the N digital multiple tones form a frequency sequence pattern between the first frequency and the second frequency;
copying the N digital multiple tones onto N different wavelength division multiplexing channels by an electro-optic element, wherein the electro-optic element is configured to generate N corresponding optical signals on each wavelength division multiplexing channel, and wherein on a first wavelength division multiplexing channel, N optical signals keep the same frequency sequence pattern, and wherein the N optical signals of the first wavelength division multiplexing channel are in a range from a third frequency to a fourth frequency, and wherein one optical signal of the N optical signals of the first wavelen

Assignees

• Huawei Tech Co Ltd

Inventors

• Jiang Zhiping
• Chen Chen
• Zhang Zhuhong
• Li Chuandong

Classifications

• H04B10/532 Primary

  Polarisation modulation · CPC title

• H04J14/02 Primary

  Wavelength-division multiplex systems · CPC title

• H04B10/5561

  Digital phase modulation · CPC title

• H04B10/506

  Multiwavelength transmitters · CPC title

• H04B10/5563

  Digital frequency modulation · CPC title