OPTICAL MODULATOR, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD

• US 20120237156A1
• Filed: 03/16/2011
• Published: 09/20/2012
• Est. Priority Date: 03/16/2011
• Status: Abandoned Application

• Current Assignee: Xieon Networks S.A.R.L. (Infinera Corp.)
• Original Assignee: Nokia Solutions and Networks US LLC (Nokia Corporation)
• Inventors: Rohde, Harald, Gottwald, Erich
• Application Number:
  US13/049,287
• Publication Number:
  US 20120237156A1
• Time in Patent Office: Days
• US Class Current: 385/3
• CPC Class Codes: H04B 10/5053 using a parallel, i.e. shunt, combination of modulators
• CPC Class Codes: H04B 10/5165 Carrier suppressed; Single sideband; Double sideband or vestigial
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An optical modulator has a first branch and a second branch, both being connectable to an input, in particular to a light source. The first branch has an amplitude modulator and a phase shifter, and the amplitude modulator is operable by a first signal that is substantially sinusoidal. The second branch has an amplitude modulator that is operable by a second signal that is substantially 90 degree phase shifted to the first signal. A combining unit with two inputs and two outputs combines the optical fields of the first and second branches. Each output is arranged to supply an optical carrier. A combined optical modulator is formed with at least one such optical modulator. Further, there is provided a method for providing several optical carriers based on an input signal.

Claims

1. An optical modulator, comprising:

a first branch and a second branch each connectable to an input;

said first branch containing an amplitude modulator and a phase shifter, said amplitude modulator in said first branch being operable by a substantially sinusoidal first signal;

said second branch containing an amplitude modulator that is operable by a second signal that is phase-shifted by substantially 90 degrees relative to the first signal;

a combining unit having two inputs and two outputs and combining the optical fields of said first branch and said second branch;

each of said outputs being arranged to supply an optical carrier.

2. The optical modulator according to claim 1, wherein said first and second branches are each connectable to a light source.

3. The optical modulator according to claim 1, comprising a two-beam interferometer.

4. The optical modulator according to claim 1, wherein said first branch and said second branch each comprises a Mach-Zehnder modulator.

5. The optical modulator according to claim 2, wherein a phase of said first branch or a phase of said second branch is adjusted to at least partially compensate a deficient suppression of a frequency of said light source.

6. The optical modulator according to claim 1, wherein each output of said combining unit is modulated with an electrical data signal into an optical output signal that is combined and conveyed via an optical fiber.

7. The optical modulator according to claim 1, which comprises a splitter connected to said output of said combining unit, a modulator connected to said splitter, and a polarization converter connected to said modulator, said polarization converter outputting a polarized output signal, and wherein the polarized output signal is combined and conveyed via an optical fiber.

8. The optical modulator according to claim 7, wherein said optical modulator comprises a third output carrying the signal of the input.

9. The optical modulator according to claim 1, configured to supply local oscillator signals in an optical component.

10. The optical modulator according to claim 9, configured to supply local oscillator signals in an optical line terminal.

11. The optical modulator according to claim 9, wherein each output of the optical modulator is connected to a receiver of the optical component.

12. A combined optical modulator, comprising a plurality of optical modulators each according to claim 1, disposed to receive a feed signal from a common light source.

13. A combined optical modulator, comprising a plurality of optical modulators each according to claim 1, said plurality of optical modulators including a first optical modulator, a second optical modulator, and a third optical modulator, said first optical modulator having a first output connected to an input of said second optical modulator and a second output connected to an input of said third optical modulator.

14. A combined optical modulator, comprising:

at least one combined optical modulator comprising a plurality of optical modulators each according to claim 1, disposed to receive a feed signal from a common light source; and

at least one combined optical modulator comprising a plurality of optical modulators each according to claim 1, said plurality of optical modulators including a first optical modulator, a second optical modulator, and a third optical modulator, said first optical modulator having a first output connected to an input of said second optical modulator and a second output connected to an input of said third optical modulator.

15. A communication system, comprising at least one optical modulator according to claim 1.

16. A communication system, comprising at least one combined optical modulator formed of a plurality of optical modulators each according to claim 1 and disposed to receive a feed signal from a common light source.

17. A communication system, comprising at least one combined optical modulator formed of a plurality of optical modulators each according to claim 1 and disposed to receive a feed signal from a common light source, and at least one combined optical modulator formed of a plurality of optical modulators each according to claim 1 and including first, second, and third optical modulators, said first optical modulator having a first output connected to an input of said second optical modulator and a second output connected to an input of said third optical modulator.

18. A method for providing a plurality of optical carriers based on an input signal, the method which comprises:

feeding an input signal by a splitter to a first branch and to a second branch;

modulating and phase-shifting the input signal by the first branch, thereby amplitude-modulating the input signal by a first, substantially sinusoidal signal;

amplitude-modulating the input signal by a second signal in the second branch, wherein the second signal is phase-shifted by substantially 90 degrees relative to the first signal;

combining the optical fields of the first branch and the second branch by a combining unit, wherein the combining unit supplies two outputs; and

wherein each of the outputs provides an optical carrier.

19. The method according to claim 18, which comprises modulating each output of the combining unit with an electrical signal.

20. The method according to claim 18, which comprises modulating each output of the combining unit with an electrical signal to form a modulated signal, and feeding the modulated signal via a combiner onto an optical fiber.