Integrated quantum information processing controlled phase gate

1. An electro-optical directional coupler, comprising:

a substrate;

a first optical waveguide formed on the substrate;

a second optical waveguide formed on the substrate, the second optical waveguide extending adjacent to and parallel with the first optical waveguide for at least one interaction length;

the at least one interaction length having a first end and a second end such that an optical signal applied only to one of the first and second optical waveguides couples to the other of the first and second optical waveguides between the first end and second end;

a first electrode comprising first, second, third, and fourth voltage sources, the first electrode proximate the first and second optical waveguides and positioned between the first end and second end of the interaction length such that a first voltage applied to the first electrode independently tunes a coupling of a TE mode, the first electrode configured to produce a horizontal E-field through the first and second optical waveguides; and

a second electrode proximate the first and second optical waveguides and the first electrode and positioned between the first end and second end of the interaction length such that a second voltage applied to the second electrode independently tunes a coupling of a TM mode,

wherein the independent tuning from the first and second applied voltages simultaneously controls the coupling of the TM and TE modes,

wherein the second and third voltages sources are positioned on the substrate such that the second and third voltage sources are between the first and second optical waveguides, and

wherein the first and fourth voltages are positioned on the substrates such that the first and second optical waveguides and the second and third voltage sources are between the first and fourth voltage sources, producing horizontal electric fields across the first and second optical waveguides.

2. The electro-optical directional coupler of claim 1 , wherein the substrate is made of a material selected from a group consisting of: Lithium Niobate, EO polymer, QD/QW III-V, and combinations thereof.

3. The electro-optical directional coupler of claim 1 , wherein the first and second optical waveguides are titanium in-diffused lithium niobate optical waveguides.

4. An electro-optical directional coupler, comprising:

a substrate;

a first optical waveguide formed on the substrate;

a second optical waveguide formed on the substrate, the second optical waveguide extending adjacent to and parallel with the first optical waveguide for at least one interaction length;

the at least one interaction length having a first end and a second end such that an optical signal applied only to one of the first and second optical waveguides couples to the other of the first and second optical waveguides between the first end and second end;

a first electrode proximate the first and second optical waveguides and positioned between the first end and second end of the interaction length such that a first voltage applied to the first electrode independently tunes a coupling of a TE mode; and

a second electrode comprising first, second, and third voltage sources, the second electrode proximate the first and second optical waveguides and the first electrode and positioned between the first end and second end of the interaction length such that a second voltage applied to the second electrode independently tunes a coupling of a TM mode, the second electrode configured to produce a vertical E-field through the first and second optical waveguides,

wherein the independent tuning from the first and second applied voltages simultaneously controls the coupling of the TM and TE modes, and

wherein the first voltage source is positioned on the substrate above the first and second optical waveguides and the second and third voltage sources are positioned on the substrate such that the first and second optical waveguides and the first voltage source are between the second and third voltage sources, producing a vertical electric field across the first and second optical waveguides.

5. A C-Phase Gate, comprising:

a substrate;

a first electro-optical directional coupler having a first and second input and a first and second output, the first electro-optical directional coupler including:

a first optical waveguide positioned on the substrate between the first input and first output of the first electro-optical directional coupler;

a second optical waveguide positioned on the substrate between the second input and second output of the first electro-optical directional coupler, the second optical waveguide extending adjacent to and parallel with the first optical waveguide for at least one first interaction length;

the at least one first interaction length having a first end and a second end such that an optical signal applied only to one of the first and second optical waveguides couples to the other of the first and second optical waveguides between the first end and second end;

a first electrode proximate the first and second optical waveguides and positioned between the first end and second end of the at least one first interaction length such that a first voltage applied to the first electrode tunes a coupling of a TE mode; and

a second electrode proximate the first and second optical waveguides and the first electrode and positioned between the first end and second end of the at least one first interaction length such that a second voltage applied to the second electrode tunes a coupling of a TM mode,

wherein the tuning from the first and second applied voltages

simultaneously controls the coupling of the TM and TE modes;

a second electro-optical directional coupler having a first and second input and a first and second output, the second electro-optical directional coupler including:

a third optical waveguide positioned on the substrate between the first input and first output of the second electro-optical directional coupler;

a fourth optical waveguide positioned on the substrate between the second input and second output of the second electro-optical directional coupler, the fourth optical waveguide extending adjacent to and parallel with the third optical waveguide for at least one second interaction length;

the at least one second interaction length having a first end and a second end such that an optical signal applied only to one of the third and fourth optical waveguides couples to the other of the third and fourth optical waveguides between the first end and second end;

a third electrode proximate the third and fourth optical waveguides and positioned between the first end and second end of the at least one second interaction length such that a third voltage applied to the third electrode tunes a coupling of a TE mode; and

a fourth electrode proximate the third and fourth optical waveguides and the third electrode and positioned between the first end and second end of the at least one second interaction length such that a fourth voltage applied to the fourth electrode tunes a coupling of a TM mode,

wherein the tuning from the third and fourth applied voltages

simultaneously controls the coupling of the TM and TE modes;

a third electro-optical directional coupler having a first and second input and a first and second output, the third electro-optical directional coupler including:

a fifth optical waveguide positioned on the substrate between the first input and first output of the third electro-optical directional coupler;

a sixth optical waveguide positioned on the substrate between the second input and second output of the third electro-optical directional coupler, the sixth optical waveguide extending adjacent to and parallel with the fifth optical waveguide for at least one third interaction length;

the at least one third interaction length having a first end and a second end such that an optical signal applied only to one of the fifth and sixth optical waveguides couples to the other of the fifth and sixth optical waveguides between the first end and second end;

a fifth electrode proximate the fifth and sixth optical waveguides and positioned between the first end and second end of the at least one third interaction length such that a fifth voltage applied to the third electrode tunes a coupling of a TE mode; and

a sixth electrode proximate the fifth and sixth optical waveguides and the fifth electrode and positioned between the first end and second end of the at least one third interaction length such that a sixth voltage applied to the sixth electrode tunes a coupling of a TM mode,

wherein the tuning from the fifth and sixth applied voltages

simultaneously controls the coupling of the TM and TE modes; and

wherein the first input and second input of the first electro-optical directional coupler are configured to receive one or more input signals, and

wherein the first output of the first electro-optical directional coupler is connected to the second input of the second electro-optical directional coupler, and

wherein the second output of the first electro-optical directional coupler is connected to the first input of the third electro-optical directional coupler.

6. The C-Phase Gate of claim 5 , wherein the substrate is made of a material selected from a group consisting of: Lithium Niobate, EO polymer, QD/QW III-V, and combinations thereof.

7. The C-Phase Gate of claim 5 , wherein the first, second, third, fourth, fifth, and sixth optical waveguides are titanium in-diffused lithium niobate optical waveguides.

8. The C-Phase Gate of claim 5 , wherein the first, third, and fifth electrodes are configured to produce a horizontal E-field through the respective first and second, third and fourth, and fifth and sixth optical waveguides.

9. The C-Phase Gate of claim 8 , wherein the horizontal E-field produced in the first electro-optical directional coupler results in a % T of H=100% and the horizontal E-fields produced in the second and third electro-optical directional couplers result in a % T of H=33%.

10. The C-Phase Gate of claim 5 , wherein the second, fourth, and sixth electrodes are configured to produce a vertical E-field through the respective first and second, third and fourth, and fifth and sixth optical waveguides.

11. The C-Phase Gate of claim 10 , wherein the vertical E-field produced in the first electro-optical directional coupler results in a % T of V=33% and the vertical E-fields produced in the second and third electro-optical directions couplers result in a % T of V=100%.