Method and circuit for encoding multi-level pulse amplitude modulated signals using integrated optoelectronic devices

• US 8,238,014 B2
• Filed: 09/08/2009
• Issued: 08/07/2012
• Est. Priority Date: 09/08/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Luxtera Incorporated (Cisco Systems, Inc.)
• Inventors: Kucharski, Daniel, Welch, Brian, Abdalla, Sherif
• Primary Examiner(s): Mack, Ricky
• Assistant Examiner(s): SAHLE, MAHIDERE S
• Application Number:
  US12/555,291
• Publication Number:
  US 20100060972A1
• Time in Patent Office: 1,064 Days
• Field of Search: 359/238, 359/245, 359/279, 385/1, 385/2, 385/3, 385/41, 372/26
• US Class Current: 359/238
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02F 1/0121 Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/212 Mach-Zehnder type
• CPC Class Codes: G02F 1/225 in an optical waveguide structure
• CPC Class Codes: G02F 1/2255 controlled by a high-frequency electromagnetic component in an electric waveguide structure
• CPC Class Codes: G02F 2201/58 Arrangements comprising a monitoring photodetector
• CPC Class Codes: H04B 10/0795 Performance monitoring; Measurement of transmission parameters
• CPC Class Codes: H04B 10/505 using external modulation
• CPC Class Codes: H04B 10/5053 using a parallel, i.e. shunt, combination of modulators
• CPC Class Codes: H04B 10/5161 Combination of different modulation schemes
• CPC Class Codes: H04B 10/541 Digital intensity or amplitude modulation

Abstract

Methods and systems for encoding multi-level pulse amplitude modulated signals using integrated optoelectronics are disclosed and may include generating a multi-level, amplitude-modulated optical signal utilizing an optical modulator driven by two or more electrical input signals. The optical modulator may include optical modulator elements coupled in series and configured into groups. The number of optical modular elements and groups may configure the number of levels in the multi-level amplitude modulated optical signal. Unit drivers may be coupled to each of the groups. The electrical input signals may be synchronized before communicating them to the unit drivers utilizing flip-flops. Phase addition may be synchronized utilizing one or more electrical delay lines. The optical modulator may be integrated on a single substrate, which may include one of: silicon, gallium arsenide, germanium, indium gallium arsenide, polymers, or indium phosphide. The optical modulator may include a Mach-Zehnder interferometer or one or more ring modulators.

Claims

1. A method for processing signals, the method comprising:

generating a multi-level, amplitude-modulated optical signal utilizing an optical modulator driven by two or more of a plurality of electrical input signals, wherein;

said optical modulator comprises a plurality of optical modulator elements coupled in series and configured into a plurality of groups;

a number of said optical modular elements and a number of said plurality of groups configure a number of levels in said multi-level amplitude modulated optical signal;

unit drivers are coupled to each of said plurality of groups of said optical modulator elements; and

said plurality of electrical input signals are synchronized utilizing flip-flops before being communicated to said unit drivers.

2. The method according to claim 1, comprising selecting two or more of said plurality of electrical input signals utilizing one or more multiplexers.

3. The method according to claim 2, wherein said one or more multiplexers selects an electrical input or a complement of said electrical input.

4. The method according to claim 1, comprising synchronizing phase addition in said plurality of optical modulator elements utilizing one or more electrical delay lines.

5. The method according to claim 1, wherein said optical modulator is integrated on a single substrate.

6. The method according to claim 5, wherein said single substrate comprise one of:

silicon, gallium arsenide, germanium, indium gallium arsenide, indium phosphide, or polymer-based materials.

7. The method according to claim 1, wherein said optical modulator comprises a Mach-Zehnder interferometer.

8. The method according to claim 1, wherein said optical modulator comprises one or more ring modulators.

9. A system for processing signals, the system comprising:

an optical modulator comprising one or more optical and one or more electrical components, said optical modulator being operable to generate a multi-level, amplitude-modulated optical signal, wherein;

said optical modulator is driven by two or more of a plurality of electrical input signals;

said optical modulator comprises a plurality of optical modulator elements coupled in series and configured into a plurality of groups;

a number of said optical modular elements and a number of said plurality of groups configure a number of levels in said multi-level amplitude modulated optical signal; and

said optical modulator is operable to;

couple unit drivers to each of said plurality of groups of said optical modulator elements; and

synchronize said plurality of electrical input signals utilizing flip-flops before communicating said signals to said unit drivers.

10. The system according to claim 9, wherein said optical modulator is operable to select two or more of said plurality of electrical input signals utilizing one or more multiplexers.

11. The system according to claim 10, wherein said one or more multiplexers selects an electrical input or a complement of said electrical input.

12. The system according to claim 9, wherein said optical modulator is operable to synchronize phase addition in said plurality of optical modulator elements utilizing one or more electrical delay lines.

13. The system according to claim 9, wherein said optical modulator is integrated on a single substrate.

14. The system according to claim 13, wherein said single substrate comprise one of:

silicon, gallium arsenide, germanium, indium gallium arsenide, indium phosphide, or polymer-based materials.

15. The system according to claim 9, wherein said optical modulator comprises a Mach-Zehnder interferometer.

16. The system according to claim 9, wherein said optical modulator comprises one or more ring modulators.

17. A method for processing signals, the method comprising:

generating a multi-level, amplitude-modulated optical signal utilizing an optical modulator driven by two or more of a plurality of electrical input signals, wherein;

said optical modulator comprises a plurality of optical modulator elements coupled in series and configured into a plurality of groups; and

a number of said optical modular elements and a number of said plurality of groups configure a number of levels in said multi-level amplitude modulated optical signal; and

two or more of said plurality of electrical input signals are selected utilizing one or more multiplexers.

18. The method according to claim 17, wherein said one or more multiplexers selects an electrical input or a complement of said electrical input.

19. A system for processing signals, the system comprising:

an optical modulator comprising one or more optical and one or more electrical components, said optical modulator being operable to generate a multi-level, amplitude-modulated optical signal, wherein;

said optical modulator is driven by two or more of a plurality of electrical input signals;

said optical modulator comprises a plurality of optical modulator elements coupled in series and configured into a plurality of groups;

a number of said optical modular elements and a number of said plurality of groups configure a number of levels in said multi-level amplitude modulated optical signal; and

said optical modulator is operable to select two or more of said plurality of electrical input signals utilizing one or more multiplexers.

20. The system according to claim 19, wherein said one or more multiplexers selects an electrical input or a complement of said electrical input.