Distributed CMOS driver with enhanced drive voltage for silicon optical push-pull Mach-Zehnder modulators

Patent metadata

Field	Value
Publication number	US-10488682-B2
Application number	US-201414475503-A
Country	US
Kind code	B2
Filing date	Sep 2, 2014
Priority date	Aug 31, 2013
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Disclosed are structures and methods for CMOS drivers that drive silicon optical push-pull Mach-Zehnder modulators (MZMs) with twice the drive voltage per interferometer arm as with prior art designs.

First claim

The invention claimed is:

1. A silicon optical modulator driver comprising:
driver circuitry configured to:
electrically drive, with a first driver, a first plurality of diodes with a first modulating signal, the first plurality of diodes disposed at differing locations on a first common optical waveguide arm of a Mach-Zehnder optical modulator;
electrically drive, with a second driver different than the first driver, a second plurality of diodes with a second modulating signal, the second plurality of diodes disposed at differing locations on a second common optical waveguide arm of the Mach-Zehnder optical modulator;

wherein at least a first diode of the first plurality of diodes is electrically connected in parallel to at least a second diode of the second plurality of diodes.

2. A method comprising:
electrically driving, with a first driver, a first waveguide arm of a Mach-Zehnder optical modulator and, with a second driver different than the first driver, a second waveguide arm of the Mach-Zehnder optical modulator by providing a first modulating voltage to a first plurality of diodes disposed at differing locations on the first waveguide arm and a second modulating voltage to a second plurality of diodes disposed at differing locations on the second waveguide arm;
wherein at least a first diode of the first plurality of diodes is electrically connected in parallel to at least a second diode of the second plurality of diodes.

3. The method of claim 2 , further comprising electrically biasing at least the first diode of the first plurality of diodes using a capacitor connected in series to the first diode of the first plurality of diodes.

4. A Mach-Zehnder optical modulator comprising:
a first waveguide arm of the Mach-Zehnder optical modulator optically coupled to an input waveguide and to an output waveguide;
a second waveguide arm of the Mach-Zehnder optical modulator optically coupled to the input waveguide and to the output waveguide;
a first plurality of diodes disposed at differing locations on the first waveguide arm;
a second plurality of diodes disposed at differing locations on the second waveguide arm;
a first driver coupled to the first plurality of diodes; and
a second driver different than the first driver and coupled to the second plurality of diodes,
wherein at least a first diode of the first plurality of diodes is electrically connected in parallel to at least a second diode of the second plurality of diodes.

5. The Mach-Zehnder optical modulator of claim 4 , further comprising control circuitry configured to electrically drive, with the first driver, the first plurality of diodes and, with the second driver, the second plurality of diodes.

6. The Mach-Zehnder optical modulator of claim 4 , further comprising a plurality of capacitors, wherein at least one capacitor of the plurality of capacitors is disposed in series to a corresponding diode of the first plurality of diodes.

7. The Mach-Zehnder optical modulator of claim 6 , wherein each capacitor of the plurality of capacitors is disposed in series to a respective diode of the first plurality of diodes.

8. The Mach-Zehnder optical modulator of claim 4 , wherein the first and the second waveguide arms are made of silicon.

9. The Mach-Zehnder optical modulator of claim 4 , wherein the first diode of the first plurality of diodes has a cathode electrically coupled to an anode of the second diode of the second plurality of diodes.

10. The Mach-Zehnder optical modulator of claim 4 , wherein the first diode of the first plurality of diodes has an anode electrically coupled to a cathode of the second diode of the second plurality of diodes.

11. The silicon optical modulator driver of claim 1 , wherein the driver circuitry is further configured to electrically bias at least the first diode of the first plurality of diodes using a capacitor connected in series to the first diode of the first plurality of diodes.

12. The silicon optical modulator driver of claim 1 , wherein the first diode of the first plurality of diodes has an anode electrically coupled to a cathode of the second diode of the second plurality of diodes.

13. The method of claim 2 , wherein electrically driving the first waveguide arm of the Mach-Zehnder optical modulator comprises matching an optical group velocity of an optical mode propagating along the first waveguide arm with the first modulating voltage.

Assignees

• Acacia Communications Inc

Inventors

• Doerr Christopher

Classifications

• G02F1/225

  in an optical waveguide structure · CPC title

• G02F1/218

  using semi-conducting materials · CPC title

• G02F2201/126

  push-pull · CPC title

• G02F1/0121 Primary

  Operation of devices; Circuit arrangements, not otherwise provided for in this subclass · CPC title

• G02F2001/212

  Physics · mapped topic