Flexible optical waveguides and methods for manufacturing flexible optical waveguides
The material stack of the present disclosure can be used for fabricating optical waveguides that are thin and flexible, and that can bend light around small turns. The stack of materials can include a polymer core and a cladding, which together can create a large difference in refractive index. As a result, light can remain within the core even when bent around radii where standard glass fibers could fail.
1. A method to manufacture an implantable optrode, comprising:
depositing a resist layer over a substrate layer;
patterning the resist layer;
depositing a metal layer over the patterned resist layer;
removing the patterned resist layer to form at least one electrode and at least one contact pad;
depositing a first cladding layer comprising a fluoropolymer such that a first face of the first cladding layer faces towards the substrate layer;
treating at least a first portion of a second face of the first cladding layer, opposite the substrate layer, with a fluoropolymer etchant to change a surface energy of the second face of the first cladding layer;
depositing a core material on the at least the first portion of the second face of the first cladding layer;
encapsulating the core material with a second cladding layer, such that a portion of a first face of the second cladding layer faces towards the substrate layer;
machining one or more channels into the implantable optrode to form one or more microfluidic channels in the implantable optrode; and
mounting a second face of the second cladding layer, opposite the first face of the second cladding layer, to a backing film, wherein a portion of the metal layer is exposed to an external environment through the substrate layer responsive to mounting the second face of the second cladding layer to the backing film.
2. The method of claim 1 , wherein the core material comprises at least one of poly(methyl methacrylate) (PMMA), SU-8, or parylene.
3. The method of claim 2 , wherein the change to the surface energy of the first face of the first cladding layer is configured to enable the core material to bond with the first cladding layer.
4. The method of claim 1 , further comprising etching or patterning the core material to form a waveguide.
5. The method of claim 4 , wherein the waveguide has a width between about 10 μm and about 1 mm.
6. The method of claim 4 , wherein the waveguide has a thickness between about 10 μm and about 1 mm.
7. The method of claim 4 , wherein the waveguide comprises at least one turn with a diameter between about 50 μm and about 1000 μm.
8. The method of claim 1 , further comprising:
depositing a release layer onto a silicon wafer; and
depositing the substrate layer on the release layer.
9. The method of claim 8 , wherein the substrate layer is between about 10 μm and about 30 μm.
10. The method of claim 1 , wherein the first cladding layer at least partially encapsulates the metal layer.
11. The method of claim 10 , further comprising drilling through the first cladding layer and the second cladding layer to expose the portion of the metal layer to the external environment.
12. The method of claim 1 , wherein the metal layer comprises at least one of chromium, gold, or titanium.
13. The method of claim 1 , further comprising depositing a second metal layer on the metal layer.
14. The method of claim 1 , wherein the metal layer is between about 1 μm and about 5 μm thick.
15. The method of claim 1 , wherein the first cladding layer comprises at least one of poly(perfluorobutenyl vinyl ether) or 3-Methyl-1,2-cyclopentanedione.
16. The method of claim 1 , wherein the first cladding layer is between about 2 μm and about 10 μm thick.
17. The method of claim 1 , further comprising forming a plurality of waveguides in the core material.
18. The method of claim 1 , further comprising forming, in the core material, one or more of a waveguide slitter, a curved waveguide, a tapering waveguide, or a lens.
19. The method of claim 1 , further comprising depositing a second layer of the core material and a third cladding layer to define a second waveguide in the implantable optrode.