Liquid overclad-encapsulated optical device

• US 20010024556A1
• Filed: 01/16/2001
• Published: 09/27/2001
• Est. Priority Date: 03/23/2000
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Beguin, Alain M.J., Renvaze, Christophe F.P.
• Granted Patent: US 6,587,626 B2
• Time in Patent Office: Days
• US Class Current: 385/125
• CPC Class Codes: G02B 2006/0325 Fluid core or cladding
• CPC Class Codes: G02B 6/122 Basic optical elements, e.g. light-guiding paths
• CPC Class Codes: G02B 6/3514 the reflective optical element moving along a line so as to translate into and out of the beam path, i.e. across the beam path
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation
• CPC Class Codes: G02B 6/3596 With planar waveguide arrangement, i.e. in a substrate, regardless if actuating mechanism is outside the substrate

Abstract

An optical device includes a planar substrate (10) on top of which is deposited a layer of waveguide material (402). A waveguide circuit (404) is etched into the waveguide material (402). A cover (426) selectively encapsulates the substrate (10) around the waveguide circuit (404) while leaving space to provide a gap above the waveguide circuit (404). A liquid material (30) having a lower index of refraction than the waveguide material is filled into the gap above the waveguide circuit (404) such that the liquid acts as an overclad for the waveguide circuit (404).

Claims

1. An optical device comprising:

an optical path characterized by a refractive index, for propagating a light signal;

an optical modifying element disposed in the optical path for modifying the light signal; and

an overclad liquid having a refractive index less than the refractive index of the optical path disposed between the optical path and the optical modifying element for reducing optical loss of the light signal.

2. The optical device of

claim 1

wherein the optical path comprises a waveguide.

3. The optical device of

claim 2

wherein the overclad liquid has the refractive index lower than the waveguide.

4. The optical device of

claim 1

wherein the optical path comprises a waveguide core.

5. The optical device of

claim 1

wherein the optical path comprises a waveguide having a core layer disposed on top of a substrate.

6. The optical device of

claim 5

wherein the overclad liquid has the refractive index less than the core layer.

7. The optical device of

claim 1

further comprising a cover for enclosing the overclad liquid within the optical path.

8. The optical device of

claim 1

wherein the optical path comprises a waveguide circuit.

9. An optical device comprising:

an optical planar substrate;

a waveguide core having a refractive index, the waveguide core disposed on the optical planar substrate for providing an optical path for propagating a light signal;

an optical modifying element optically coupled to the waveguide core for modifying the light signal; and

an overclad liquid having a refractive index less than the refractive index of the waveguide core disposed between the waveguide core and the optical modifying element for reducing optical loss of the light signal.

10. An optical device comprising:

a planar substrate;

a layer of waveguide material deposited on the planar substrate, the layer of waveguide material having a waveguide circuit etched into the waveguide material;

a cover for selectively encapsulating the substrate around the waveguide circuit while leaving space to provide a gap above the waveguide circuit; and

a liquid material having a lower index of refraction than the waveguide material filled into the gap above the waveguide circuit such that the liquid acts as an overclad for the waveguide circuit.

11. A method for fabricating a planar optical device, the method comprising the following steps:

providing a planar substrate;

depositing a layer of waveguide material onto the planar substrate;

etching a waveguide circuit into the waveguide material;

encapsulating the substrate around the waveguide circuit to provide a gap above the waveguide circuit; and

filling the gap above the waveguide circuit with a liquid material having a lower index of refraction than the waveguide material such that the liquid acts as an overclad for the waveguide circuit.

12. The method of

claim 11

wherein the encapsulating step comprises the following steps:

depositing a solid overclad material layer on the waveguide material;

forming an opposed pair of overclad sidewalls at opposed edges of the planar substrate by removing the solid overclad layer from the waveguide material away from the opposed edges of the planar substrate;

mounting a cover on top of the opposed pair of overclad sidewalls for covering the planar substrate.

13. The method of

claim 11

wherein the encapsulating step comprises the following steps:

selectively depositing a solid overclad material layer on the waveguide material and forming an opposed pair of overclad sidewalls at opposed edges of the planar substrate by removing the solid overclad layer from the waveguide material away from the opposed edges of the planar substrate in a single selective deposition step; and

mounting a cover on top of the opposed pair of overclad sidewalls for covering the planar substrate.

14. The method of

claim 11

further comprising inserting an optical modifying element disposed in the waveguide circuit for modifying a light signal.

15. The method of

claim 14

wherein the inserting step comprises inserting a MEMS mirror of a MEMS substrate in the waveguide circuit for modifying the light signal.

16. The method of

claim 15

further comprising the following steps:

etching a trench in the waveguide circuit such that the light signal follows a reflected optical path if the MEMS mirror is in a reflected state in the trench;

forming at least one flip-chip solder bump on the planar substrate on opposed sides of the trench; and

flip-chip attaching the MEMS substrate on top of the flip-chip solder bumps wherein the MEMS mirror is slidable within the trench for covering a major portion of the trench.

17. The method of

claim 16

wherein the etching step comprises providing access to the waveguide material by etching a trench through the waveguide circuit.

18. The method of

claim 17

wherein the encapsulating step comprises the following steps:

selectively depositing a solid overclad material layer on the waveguide material;

forming an opposed pair of overclad sidewalls at opposed edges of the planar substrate by removing the solid overclad layer from the waveguide material away from the trench and away from the opposed edges of the planar substrate; and

sealing the MEMS substrate to the opposed pair of overclad sidewalls as a cover for covering the planar substrate.

19. The method of

claim 17

wherein the encapsulating step comprises the following steps:

pigtailing on opposed edges of the planar substrate for forming an opposed pair of pigtail blocks; and

enclosing the MEMS substrate with a cover sealed to the opposed pair of pigtail blocks as a cover for enclosing the planar substrate.

20. The method of

claim 11

wherein the filling step comprises filling the gap with the liquid material having a fluorinated compound.