Method and system for a distributed optical transmitter with local domain splitting

• US 10,425,165 B1
• Filed: 11/13/2018
• Issued: 09/24/2019
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Luxtera Incorporated (Cisco Systems, Inc.)
• Inventors: Welch, Brian, Xu, Xuelin
• Primary Examiner(s): Sandhu, Amritbir K
• Application Number:
  US16/188,899
• Time in Patent Office: 315 Days
• Field of Search: 398182-191
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: H04B 10/5053 using a parallel, i.e. shunt, combination of modulators
• CPC Class Codes: H04B 10/5055 using a pre-coder
• CPC Class Codes: H04B 10/516 Details of coding or modulation
• CPC Class Codes: H04B 10/524 Pulse modulation
• CPC Class Codes: H04B 10/541 Digital intensity or amplitude modulation

Abstract

Methods and systems for a distributed optical transmitter with local domain splitting is disclosed and may include, in an optical modulator integrated in a silicon photonics chip: receiving electrical signals, communicating the electrical signals to domain splitters along a length of waveguides of the optical modulator utilizing one or more delay lines, generating electrical signals in voltage domains utilizing the domain splitters, modulating received optical signals in the waveguides of the optical modulator by driving diodes with the electrical signals generated in the voltage domains, and generating a modulated output signal through interference of the modulated optical signal in the waveguides of the optical modulator. The delay lines may comprise one delay element per domain splitter, or may comprise a delay element per domain splitter for a first subset of the domain splitters and more than one delay element per domain splitter for a second subset of the domain splitters.

Claims

1. A method for optical communication, the method comprising:

in an optical modulator;

communicating one or more first electrical signals to domain splitters along a length of waveguides of the optical modulator utilizing one or more delay lines;

generating second electrical signals in at least two voltage domains utilizing the domain splitters;

modulating received optical signals in the waveguides of the optical modulator by driving diodes with the second electrical signals generated in the at least two voltage domains; and

generating a modulated output signal through interference of the modulated received optical signals in the waveguides of the optical modulator.

2. The method according to claim 1, wherein the one or more delay lines comprise one delay element per domain splitter.

3. The method according to claim 1, wherein the one or more delay lines comprise a delay element per domain splitter for each of a first subset of the domain splitters and more than one delay element per domain splitter for a second subset of the domain splitters.

4. The method according to claim 3, wherein the optical modulator comprises a first input coupled to the first subset of the domain splitters and a second input coupled to the second subset of the domain splitters.

5. The method according to claim 4, comprising generating a 4-level pulse amplitude modulated (PAM-4) output signal using the one or more first electrical signals coupled to the first input and the second input.

6. The method according to claim 1, wherein each of the domain splitters receives a differential input signal for generating the second electrical signals in the at least two voltage domains.

7. The method according to claim 1, comprising generating the received optical signals in the waveguides of the optical modulator using a continuous wave (CW) laser signal.

8. The method according to claim 1, wherein the optical modulator comprises a Mach-Zehnder Interferometer modulator.

9. The method according to claim 1, comprising driving each of the diodes utilizing two drivers with inputs coupled to one of the domain splitters.

10. The method according to claim 1, wherein the one or more delay lines comprise an array of complementary metal-oxide semiconductor (CMOS) inverters in series.

11. A system for communication, the system comprising:

an optical modulator, the optical modulator being operable to;

communicate one or more first electrical signals to domain splitters along a length of waveguides of the optical modulator utilizing one or more delay lines;

generate second electrical signals in at least two voltage domains utilizing the domain splitters;

modulate received optical signals in the waveguides of the optical modulator by driving diodes with the second electrical signals generated in the at least two voltage domains; and

generate a modulated output signal through interference of the modulated received optical signals in the waveguides of the optical modulator.

12. The system according to claim 11, wherein the one or more delay lines comprise one delay element per domain splitter.

13. The system according to claim 11, wherein the one or more delay lines comprise a delay element per domain splitter for each of a first subset of the domain splitters and more than one delay element per domain splitter for a second subset of the domain splitters.

14. The system according to claim 13, wherein the optical modulator comprises a first input coupled to the first subset of the domain splitters and a second input coupled to the second subset of the domain splitters.

15. The system according to claim 14, wherein the optical modulator is operable to generate a 4-level pulse amplitude modulated (PAM-4) output signal using the one or more first electrical signals coupled to the first input and the second input.

16. The system according to claim 11, wherein each of the domain splitters receives a differential input signal for generating the second electrical signals in the at least two voltage domains.

17. The system according to claim 11, wherein the optical modulator is operable to receive the optical signals in the waveguides of the optical modulator from a continuous wave (CW) laser signal.

18. The system according to claim 11, wherein the optical modulator comprises a Mach-Zehnder Interferometer modulator.

19. The system according to claim 11, wherein the optical modulator is operable to drive each of the diodes utilizing two drivers with inputs coupled to one of the domain splitters.

20. A system for communication, the system comprising:

an optical modulator, the optical modulator comprising;

a pair of optical waveguides; and

local modulator sections arranged along the pair of optical waveguides, wherein each local modulator comprises a diode arranged in each optical waveguide, a pair of diode drivers connected to each diode, and a domain splitter that is operable to generate separate voltage domains for the pair of diode drivers.