Piezoelectric deformable photonic devices

Patent metadata

Field	Value
Publication number	US-11569431-B1
Application number	US-202016989535-A
Country	US
Kind code	B1
Filing date	Aug 10, 2020
Priority date	Aug 19, 2019
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A CMOS-compatible actuator platform for implementing phase, amplitude, and frequency modulation in silicon nitride photonic integrated circuits via piezo-optomechanical coupling using tightly mechanically coupled aluminum nitride actuators is disclosed. The platform, which may be fabricated in a CMOS foundry, enables scalable active photonic integrated circuits for visible wavelengths, and the piezoelectric actuation functions without performance degradation down to cryogenic operating temperatures. A number of devices are possible, including ring modulator devices, phase shifter devices, Mach-Zehnder interferometer devices, directional coupler devices (including tunable directional coupler devices), and acousto-optic modulator and frequency shifter devices, each of which can employ the same AlN actuator platform. As all of these devices can be built on the same AlN actuator platform, numerous optical functions can be implemented on a single die.

First claim

The invention claimed is:

1. A CMOS-compatible piezoelectric deformable photonic device platform comprising:
a first contact layer adapted to route an actuation bias;
a dielectric layer formed on the first contact layer;
a second contact layer formed on the dielectric layer, the second contact layer adapted to receive a first polarity of the actuation bias;
a piezoelectric material layer formed on the second contact layer;
a third contact layer formed on the piezoelectric material layer, the third contact layer adapted to receive a second polarity of the actuation bias;
a first cladding layer formed on the third contact;
a waveguide formed on the first cladding layer, the waveguide adapted to transmit an optical signal; and
a second cladding layer formed on the waveguide;
wherein the first cladding layer and the second cladding layer are adapted to guide the optical signal in the waveguide; and
wherein the waveguide is adapted to be piezo-optomechanically coupled to the piezoelectric material when the second contact layer and the third contact layer receive the actuation bias, the piezo-optomechanical coupling inducing at least one of a strain induced photoelastic refractive index change in the waveguide and a movement of material boundaries that causes an optomechanical change to an effective refractive index of an optical mode within the waveguide.

2. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 , wherein at least a portion of the waveguide has been undercut due to removal of at least a portion of the dielectric layer.

3. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 , wherein the piezoelectric material layer includes at least one of AlN and an alloy of AlN—ScN.

4. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 , wherein the waveguide includes at least one of SiN x , Al 2 O 3 , AlN, and doped SiO 2 .

5. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 , wherein each of the first and second cladding layers includes at least one of SiO 2 and Si 3 N 4 .

6. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 ,
wherein the CMOS-compatible piezoelectric deformable photonic device platform forms a ring modulator device; and
the CMOS-compatible piezoelectric deformable photonic device platform further comprising a second waveguide, the second waveguide formed on the first cladding layer, the second cladding layer formed on the second waveguide, the second waveguide adapted to transmit a second optical signal, the second waveguide adapted to evanescently couple to the waveguide.

7. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 ,
wherein the CMOS-compatible piezoelectric deformable photonic device platform forms a phase shifter device; and
wherein the waveguide is a platform-actuated or a collinear-actuated phase shifting waveguide.

8. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 ,
wherein the CMOS-compatible piezoelectric deformable photonic device platform forms a Mach-Zehnder interferometer device;
wherein the waveguide includes:
a first coupler having an input and first and second outputs;
first and second platform-actuated or collinear-actuated phase shifting arms coupled to corresponding ones of the first and second outputs of the first coupler; and
a second coupler having first and second inputs and first and second outputs, the first and second inputs of the second coupler coupled to corresponding ones of the first and second platform-actuated or collinear-actuated phase shifting arms.

9. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 ,
wherein the CMOS-compatible piezoelectric deformable photonic device platform forms a directional coupler device;
the CMOS-compatible piezoelectric deformable photonic device platform further comprising a second waveguide, the second waveguide formed on the first cladding layer, the second cladding layer formed on the second waveguide, the second waveguide adapted to transmit a second optical signal, the second waveguide adjacent the waveguide; and
wherein the first and second cladding layers are continuous between the waveguide and the second waveguide or include a gap between the waveguide and the second waveguide.

10. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 ,
wherein the compatible piezoelectric deformable photonic device platform forms an acousto-optic modulator device;
the CMOS-compatible piezoelectric deformable photonic device platform further comprising first and second interdigital transducers (IDTs), each of the first and second IDTs including a corresponding plurality of parallel fingers; and
wherein the plurality of fingers of the first and second IDTs are adapted to be substantially parallel or substantially perpendicular to the optical signal.

11. The CMOS-compatible piezoelectric deformable photonic device platform of claim 1 , wherein the CMOS-compatible piezoelectric deformable photonic device platform forms at least two devices, each of the at least two devices including at least one of a ring modulator device, a phase shifter device, a Mach-Zehnder interferometer device, a directional coupler device, a tunable directional coupler device, an acousto-optic modulator device, and a frequency shifter device.

12. A ring modulator device comprising:
a first contact layer adapted to route an actuation bias;
a dielectric layer formed on the first contact layer;
a second contact layer formed on the dielectric layer, the second contact layer adapted to receive a first polarity of the actuation bias;
a piezoelectric material layer formed on the second contact layer;
a third contact layer formed on the piezoelectric material layer, the third contact layer adapted to receive a second polarity of the actuation bias;
a first cladding layer formed on the third contact;
first and second waveguides, each of the first and second waveguides formed on the first cladding layer, the first and second waveguides adapted to transmit corresponding first and second optical signals, the second waveguide adapted to evanescently couple to the first waveguide; and
a second cladding layer formed on the first and second waveguides;
wherein the first and second cladding layers are adapted to guide the first and second optical signals in corresponding first and second waveguides;
wherein the first waveguide is adapted to be piezo-optomechanically coupled to the piezoelectric material when the second contact layer and the third contact layer receive the actuation bias, the piezo-optomechanical coupling inducing at least one of a strain induced photoelastic refractive index change in the first waveguide and a movement of material boundaries that causes an optomechanical change to an effective refractive index of an optical mode within the first waveguide; and
wherein the ring modulator device is CMOS-compatible.

13. The ring modulator device of claim 12 , wherein at least a portion of the first waveguide has been undercut due to removal of at least a portion of the dielectric layer.

14. The ring modulator device of claim 12 , wherein the piezoelectric material layer includes at least one of AlN and an alloy of AlN—ScN.

15. The ring modulator device of claim 12 ,
wherein the first and second waveguides each includes at least one of SiN x , Al 2 O 3 , AlN, and doped SiO 2 ; and
wherein each of the first and second cladding layers includes at least

Assignees

• Nat Tech & Eng Solutions Sandia Llc

Inventors

• Eichenfield Matt
• Leenheer Andrew Jay
• Stanfield Paul

Classifications

• H01L41/0815 Primary

  Electricity · mapped topic

• G02F1/0134

  in optical waveguides · CPC title

• H01L41/18

  Electricity · mapped topic

• G02B6/3578

  Piezoelectric force (piezoelectric forces controlling reflecting elements in general G02B26/0858; piezo-optic devices G02F1/0131) · CPC title

• H01L41/083

  Electricity · mapped topic