Efficient photonic couplers for photonic waveguides and methods of forming the same
View Patent ↗An embodiment photonic device may include a dielectric waveguide having a core portion, a cladding portion, and a first photonic coupler. The first photonic coupler may include a first dielectric pillar formed at a first surface of the cladding portion and optically coupled to the core portion, and a first dielectric cap optically coupled to the first dielectric pillar. Each of the first dielectric pillar and the first dielectric cap may include a polymer material that is transparent to infrared radiation such that radiation incident on the first dielectric cap from the core portion is focused by the first dielectric cap to a beam width that is smaller than a width of the core portion of the dielectric waveguide. Some embodiments may include a second photonic coupler having a second dielectric pillar optically coupled to the core portion, and a second dielectric cap optically coupled to the second dielectric pillar.
1 . A method of forming a photonic device, comprising:
irradiating a region of a cladding material with laser radiation in a laser-writing operation to thereby form a core portion of a waveguide, wherein the core portion extends to a first surface of the cladding material;
forming a first dielectric pillar at the first surface of the cladding material such that the first dielectric pillar is optically coupled to the core portion; and
forming a first dielectric cap that is attached to and optically coupled to the first dielectric pillar.
2 . The method of claim 1 , wherein:
forming the first dielectric pillar further comprises:
forming a layer of a radiation-curable polymer over the first surface of the cladding material such that the radiation-curable polymer is formed in contact with a core surface of the core portion; and
irradiating the radiation-curable polymer in a localized region over the first surface of the cladding material to thereby form the first dielectric pillar comprising a cured region of the radiation-curable polymer; and
forming the first dielectric cap further comprises:
forming a portion of the radiation-curable polymer over the first dielectric pillar; and
irradiating the portion of the radiation-curable polymer to thereby form the first dielectric cap.
3 . The method of claim 2 , wherein irradiating the radiation-curable polymer in the localized region further comprises introducing the laser radiation into the core portion of the waveguide such that the laser radiation is incident on the radiation-curable polymer from the core portion of the waveguide and is thereby absorbed by the radiation-curable polymer to thereby form the first dielectric pillar.
4 . The method of claim 1 , further comprising:
forming a second dielectric pillar at a second surface of the cladding material such that the second dielectric pillar is optically coupled to the core portion; and
forming a second dielectric cap that is attached to and optically coupled to the second dielectric pillar.
5 . A method of forming a photonic device, comprising:
forming a mask layer on a first side of a cladding material;
irradiating the mask layer with laser radiation to cause ablation of the mask layer to generate an aperture in the mask layer;
irradiating a region of the cladding material with laser radiation in a laser-writing operation forming a core portion of a waveguide, wherein the core portion extends to a first surface of the cladding material;
forming a first dielectric pillar at the first surface of the cladding material such that the first dielectric pillar is optically coupled to the core portion; and
forming a first dielectric cap that is attached to and optically coupled to the first dielectric pillar.
6 . The method of claim 5 , wherein the mask layer comprises a material that is opaque to ultraviolet radiation.
7 . The method of claim 6 , wherein the mask layer comprises one of silicon nitride, silicon dioxide, tantalum pentoxide, aluminum oxide, titanium dioxide, zirconium dioxide, or boron nitride.
8 . The method of claim 5 , wherein the aperture in the mask layer is configured to confine the laser radiation to the core portion during formation of the first dielectric pillar.
9 . The method of claim 5 , wherein forming the first dielectric pillar further comprises:
forming a layer of a radiation-curable polymer over the first surface of the cladding material such that the radiation-curable polymer is formed in contact with a core surface of the core portion; and
irradiating the radiation-curable polymer in a localized region over the first surface of the cladding material to form the first dielectric pillar comprising a cured region of the radiation-curable polymer.
10 . The method of claim 9 , further comprising placing a glass slide in contact with the radiation-curable polymer to mechanically support the radiation-curable polymer.
11 . The method of claim 9 , wherein irradiating the radiation-curable polymer in the localized region further comprises introducing the laser radiation into the core portion of the waveguide such that the laser radiation is incident on the radiation-curable polymer from the core portion of the waveguide, wherein the cured region is self-aligned with the core portion.
12 . The method of claim 5 , further comprising:
removing the mask layer;
forming a second dielectric pillar at a second surface of the cladding material such that the second dielectric pillar is optically coupled to the core portion; and
forming a second dielectric cap that is attached to and optically coupled to the second dielectric pillar.
13 . A method of forming a photonic device, comprising:
irradiating a plurality of regions of a cladding material with laser radiation in a laser-writing operation forming a plurality of core portions of a plurality of dielectric waveguides;
forming a plurality of dielectric pillars at a surface of the cladding material such that each of the plurality of dielectric pillars is optically coupled to a respective one of the plurality of core portions; and
forming a plurality of dielectric caps, each attached to and optically coupled to a respective one of the plurality of dielectric pillars.
14 . The method of claim 13 , wherein the plurality of dielectric waveguides is formed as part of a planar lightwave circuit.
15 . The method of claim 14 , wherein the plurality of dielectric waveguides comprises a fan-out configuration.
16 . The method of claim 13 , wherein the plurality of dielectric waveguides is arranged in a three-dimensional configuration within the cladding material.
17 . The method of claim 13 , wherein a first one of the plurality of dielectric pillars is formed at a first surface of the cladding material that is different from a second surface of the cladding material on which a second one of the plurality of dielectric pillars is formed.
18 . The method of claim 13 , wherein each of the plurality of dielectric pillars and each of the plurality of dielectric caps comprise a polymer material that is transparent to infrared radiation.
19 . The method of claim 13 , wherein forming the plurality of dielectric pillars further comprises:
forming a layer of a radiation-curable polymer over the surface of the cladding material; and
irradiating the radiation-curable polymer in localized regions over the surface of the cladding material to form the plurality of dielectric pillars comprising cured regions of the radiation-curable polymer.
20 . The method of claim 13 , wherein each of the plurality of dielectric caps is configured such that radiation incident on the dielectric cap from a respective one of the plurality of dielectric waveguides is focused by the dielectric cap to a beam width that is smaller than a width of the respective core portion.