Shielding structures between optical waveguides
Methods and structures for shielding optical waveguides are provided. A method includes forming a first optical waveguide core and forming a second optical waveguide core adjacent to the first optical waveguide core. The method also includes forming an insulator layer over the first optical waveguide core and the second optical waveguide core. The method further includes forming a shielding structure in the insulator layer between the first optical waveguide core and the second optical waveguide core.
1. An optical waveguide device, comprising:
a first optical waveguide core directly on and in contact with an insulator layer;
a second optical waveguide core adjacent to the first optical waveguide core;
an upper insulator layer formed directly on surfaces of the first optical waveguide core and on surfaces of the second optical waveguide core; and
a shielding structure in a trench in the upper insulator layer between the first optical waveguide core and the second optical waveguide core, the shielding structure comprising a material configured to prevent the transmission of light from the first optical waveguide core to the second optical waveguide core,
wherein the first optical waveguide core and the second optical waveguide core each comprise silicon; and
the insulator layer and the upper insulator layer each comprise oxide.
2. The device of claim 1 , wherein the shielding structure comprises a highly absorptive material in the trench in the upper insulator layer.
3. The device of claim 2 , wherein the highly absorptive material comprises Germanium.
4. The device of claim 2 , wherein the highly absorptive material comprises C doped SiCOH.
5. The device of claim 2 , wherein the highly absorptive material comprises tungsten oxide (WO 3 ).
6. The device of claim 2 , wherein the highly absorptive material comprises semiquinones (polyether poly-4).
7. The device of claim 2 , wherein the highly absorptive material comprises dinuclear mixed-valence ruthenium (Ru) complexes.
8. The device of claim 2 , wherein the highly absorptive material comprises poly(3,4-ethylenedioxythiophene) (PEDOT).
9. The device of claim 2 , wherein the highly absorptive material is a material having an optical absorbance of at least 0.1 μm at the wavelength of light propagated in the first optical waveguide core and the second optical waveguide core.
10. The device of claim 2 , wherein the highly absorptive material is a material in which light intensity is reduced by a factor of 1/e within two to three microns.
11. The device of claim 1 , wherein the first optical waveguide core and the second optical waveguide core each contact the insulator layer.
12. The device of claim 11 , wherein the insulator layer is on and contacting a substrate comprising silicon.
13. The device of claim 12 , wherein:
the substrate has a thickness of 500 μm to 700 μm;
the insulator layer has a thickness of 1.0 μm to 15 μm; and
the first optical waveguide core and the second optical waveguide core each has a thickness of 0.1 μm to 0.3 μm.
14. An optical waveguide device, comprising:
a first optical waveguide core directly on an insulator layer;
a second optical waveguide core adjacent to the first optical waveguide core;
an upper insulator layer formed directly on surfaces of the first optical waveguide core and on surfaces of the second optical waveguide core; and
a shielding structure in a trench in the upper insulator layer between the first optical waveguide core and the second optical waveguide core, wherein the shielding structure comprises a highly absorptive material configured to prevent the transmission of light from the first optical waveguide core to the second optical waveguide core and the upper insulating layer is comprised of a material different from the material of the shielding structure;
the first optical waveguide core and the second optical waveguide core comprise single crystal silicon; and
the highly absorptive material comprises one of: C doped SiCOH, and tungsten oxide (WO 3 ).
15. The device of claim 14 , wherein:
the insulator layer and the upper insulator layer each comprise oxide; and
the insulator layer is on and contacting a silicon substrate.
16. An optical waveguide device, comprising:
a first optical waveguide core directly on an insulator layer;
a second optical waveguide core adjacent to the first optical waveguide core;
an upper insulator layer formed directly on surfaces of the first optical waveguide core and on surfaces of the second optical waveguide core; and
a shielding structure in a trench in the upper insulator layer between the first optical waveguide core and the second optical waveguide core, the shielding structure comprising a material configured to prevent the transmission of light from the first optical waveguide core to the second optical waveguide core, wherein the material of the upper insulator layer is different from the material of the shielding structure,
wherein the shielding structure is between a bend of the first optical waveguide core and a bend of the second optical waveguide core.
17. The device of claim 16 , wherein the shielding structure comprises a highly absorptive material in the trench in the upper insulator layer and is confined to locations corresponding to the bend of the first optical waveguide core and the bend of the second optical waveguide core.
18. The device of claim 17 , wherein:
the insulator layer comprises oxide on a semiconductor substrate;
the first optical waveguide core and the second optical waveguide core comprise silicon; and
the highly absorptive material comprises one of: Germanium, C doped SiCOH, tungsten oxide (WO 3 ), semiquinones (polyether poly-4), dinuclear mixed-valence ruthenium (Ru) complexes, or poly(3,4-ethylenedioxythiophene) (PEDOT).
19. The device of claim 17 , wherein the highly absorptive material is a material having an optical absorbance of at least 0.1 μm at the wavelength of light propagated in the first optical waveguide core and the second optical waveguide core.
20. The device of claim 17 , wherein the highly absorptive material is a material in which light intensity is reduced by a factor of 1/e within two to three microns.