Optical waveguide modulator

Patent metadata

Field	Value
Publication number	US-11599005-B2
Application number	US-202117396954-A
Country	US
Kind code	B2
Filing date	Aug 9, 2021
Priority date	May 23, 2017
Publication date	Mar 7, 2023
Grant date	Mar 7, 2023

Abstract

A multi-section optical modulator and related method are disclosed wherein two waveguide arms traverse a plurality of successive modulating sections. A differential drive signal is applied separately to each waveguide arm of each modulating sections in synchronism with the transmission of light along the waveguide arms, effecting a dual differential driving of each section. By suitably selecting the number of modulating sections and the section length, a high modulation bandwidth and a high modulation efficiency may be achieved simultaneously for a given peak-to-peak voltage swing of the drive signal.

First claim

We claim:

1. A method of modulating input light, the method comprising:
receiving the input light into an input optical port of an optical modulator comprising a first waveguide arm and a second waveguide arm each extending optically in parallel between the input optical port and an output optical port, for transmitting the input light from the input optical port to the output optical port along two light paths traversing N successive modulator sections of the optical modulator, N≥2;
converting an input data signal into N differential drive signals, and providing the N differential drive signals separately to each of the N successive modulator sections of the optical modulator; and,
in each of the N successive modulator sections, applying a corresponding one of the N differential drive signals to the first waveguide arm and, in parallel, to the second waveguide arm
wherein the applying comprises:
providing the corresponding one of the N differential drive signals to a first pair of electrodes disposed within one of the N successive modulator sections so as to be electro-optically coupled to the first waveguide arm along a length portion thereof located within said modulator section, and
providing an inverted version of the corresponding one of the N differential drive signals to a second pair of electrodes disposed within said modulator section so as to be electro-optically coupled to the second waveguide arm along a length portion thereof located within said modulator section,
so as to effect a dual-differential push-pull modulation of the input light in each of the N successive modulator sections of the optical modulator.

2. The method of claim 1 comprising providing a DC bias to either cathode or anode electrodes in each of the first and second pairs of electrodes.

3. The method of claim 1 , wherein each waveguide arm comprises a plurality of semiconductor p/n junctions there along.

4. The method of claim 3 , wherein each of the semiconductor p/n junctions is configured to be operated by one of the pairs of electrode.

5. The method of claim 4 , wherein:
the corresponding one of the N differential drive signals comprises a first single-ended signal and a second single-ended signal varying complementary to the first single-ended signal,
each of the first and second pairs of electrodes comprises a cathode electrode and an anode electrode; and
wherein the applying comprises applying the first single-ended signal to the cathode electrode of the first pair of electrodes, and applying the second single-ended signal to the anode electrode of the second pair of electrodes.

6. The method of claim 1 , wherein each waveguide arm comprises a silicon optical waveguide.

7. The method of claim 3 , wherein each waveguide arm comprises a silicon optical waveguide.

8. The method of claim 4 , wherein each waveguide arm comprises a silicon optical waveguide.

9. The method of claim 5 , wherein each waveguide arm comprises a silicon optical waveguide.

10. The method of claim 3 , wherein each of the semiconductor p/n junctions is configured to be operated by one of the pairs of electrode in a carrier depletion mode.

11. An apparatus comprising:
a waveguide Mach-Zehnder modulator comprising:
N successive modulator sections, N≥2; and
a first and a second waveguide arm each extending optically in parallel between an input port and an output port, for transmitting input light from the input port to the output port along two light paths traversing the N successive modulator sections;
wherein each of the N successive modulator sections comprises a first pair of electrodes electro-optically coupled to the first waveguide arm along a length portion thereof located within said modulator section, and a second pair of electrodes electro-optically coupled to the second waveguide arm along a length portion thereof located within said modulator section; and,
wherein the first pair of electrodes is configured to receive a first differential drive signal and the second pair of electrodes is configured to receive a second differential drive signal, wherein the second differential drive signal is an inverted version of the first differential drive signal, so as to effect a dual-differential push-pull modulation of the input light in each of the N successive modulator sections.

12. The apparatus of claim 11 wherein the first differential drive signal and the second differential drive signal are provided by an electrical drive circuit.

13. The apparatus of claim 12 further comprising the electrical drive circuit.

14. The apparatus of claim 13 , wherein the electrical drive circuit comprises one or more differential drivers.

15. The apparatus of claim 13 , wherein the electrical drive circuit comprises at least two differential drivers.

16. The apparatus of claim 13 , wherein:
each of the first pair of electrodes and the second pair of electrodes of at least one of the N successive modulator sections comprises a cathode electrode and an anode electrode; and
the electrical drive circuit comprises a first differential driver electrically connected to the cathode electrodes of the at least one of the N successive modulator sections, and a second differential driver electrically connected to the anode electrodes of the at least one of the N modulator sections.

17. The apparatus of claim 16 wherein each of the cathode electrode and anode electrode comprises a first end and a second end, wherein the first and second differential drivers are electrically coupled to the first ends of respective cathode or anode electrodes, and wherein the apparatus is configured according to one of the following configurations:
the second ends of the anode electrodes are grounded and the second ends of the cathode electrodes are connected to a source of DC voltage, or
the second ends of the cathode electrodes are grounded and the second ends of the anode electrodes are connected to a source of DC voltage.

18. The apparatus of claim 16 wherein each of the first and second waveguide arms comprises a plurality of semiconductor p/n junctions located there along, and wherein each of the semiconductor p/n junctions is configured to be operated by one of the pairs of electrode.

19. The apparatus of claim 11 , wherein each waveguide arm comprises a silicon optical waveguide.

20. The apparatus of claim 16 , wherein each waveguide arm comprises a silicon optical waveguide.

21. The apparatus of claim 18 , wherein each waveguide arm comprises a silicon optical waveguide.

Assignees

• Nokia Solutions & Networks Oy

Inventors

• Williams Christopher
• Ahmed Mostafa
• Rylyakov Alexander
• Younce Richard C
• Liu Yang
• Ding Ran
• Ahmed Abdelrahman

Classifications

• G02F1/2255 Primary

  controlled by a high-frequency electromagnetic component in an electric waveguide structure · CPC title

• G02F2201/122

  having a particular pattern · CPC title

• G02F1/2257

  the optical waveguides being made of semiconducting material · CPC title

• G02F1/212

  Mach-Zehnder type · CPC title