Waveguide with controlled mode confinement for analyte interaction and optical power delivery
A photonic circuit and electronic device incorporating the same including a waveguide defining different regions having different widths and cladding thicknesses. The width and cladding thickness in a particular region are configured to loosely confine light in a first set of conditions and to tightly/highly confine light in a second set of conditions. The first and second set of conditions can correspond to the waveguide being positioned proximate to different materials having different indices of refraction.
1 . A photonic circuit comprising:
an insulator layer;
a waveguide formed on the insulator layer to a selected thickness and defining a path from an input to an output, the waveguide defining:
a first region having a first width selected for high confinement of light; and
a second region having a second width less than the first width, the second width selected for:
high confinement of light given a first condition; and
loose confinement of light given a second condition; and
a cladding layer formed over the waveguide, encapsulating the waveguide and disposed to a first thickness over the first region of the waveguide and a second thickness less than the first thickness over the second region of the waveguide,
wherein:
the cladding layer defines an interface surface configured to receive a first analyte and a second analyte;
the first condition corresponds to the first analyte being positioned on the interface surface; and
the second condition corresponds to the second analyte being positioned on the interface surface.
2 . The photonic circuit of claim 1 , wherein the waveguide is formed from silicon nitride and the cladding layer comprises silicon dioxide.
3 . The photonic circuit of claim 1 , wherein:
the first analyte has a first index of refraction; and
the second analyte has a second index of refraction different from the first index of refraction.
4 . The photonic circuit of claim 3 , wherein the second width and the second thickness are selected to exhibit loose confinement when the interface surface contacts a material with the second index of refraction.
5 . The photonic circuit of claim 3 , wherein the first index of refraction is lower than the second index of refraction.
6 . The photonic circuit of claim 3 , wherein:
the second index of refraction is that of human hair; and
the first index of refraction is one of:
skin;
air;
water; or
shaving lubricant.
7 . The photonic circuit of claim 1 , comprising an input facet optically coupled to the input of the waveguide, the input facet configured to optically couple to one of a photonic routing circuit or a laser light source.
8 . The photonic circuit of claim 1 , wherein the waveguide has a serpentine path.
9 . An electronic device comprising:
a laser light source;
a power source coupled to the laser light source;
control electronics coupled to the power source and to the laser light source; and
a photonic circuit comprising:
a waveguide optically coupled to the laser light source, the waveguide defining:
a first region having a first width selected for high confinement of light; and
a second region having a second width less than the first width, the second width selected for:
high confinement of light given a first condition; and
loose confinement of light given a second condition; and
a cladding layer formed over the waveguide, encapsulating the waveguide and disposed to a first thickness over the first region of the waveguide and a second thickness less than the first thickness over the second region of the waveguide, the cladding layer defining an interface surface above the second region of the waveguide,
wherein:
the first condition corresponds to a first material having a first index of refraction placed proximate to the interface surface; and
the second condition corresponds to a second material having a second index of refraction placed proximate to the interface surface, the second index of refraction different from the first index of refraction.
10 . The electronic device of claim 9 , wherein:
the second material is human hair; and
the first material is one of:
skin;
air;
water; or
shave lubricant.
11 . The electronic device of claim 10 , wherein the control electronics are configured to cause the power source to power the laser light source to emit a single frequency of laser light into the waveguide, the single frequency overlapping an absorption spectrum of a chromophore within human hair.
12 . The electronic device of claim 11 , wherein output of the laser light source is configured to fracture human hair.
13 . The electronic device of claim 9 , wherein the first material is a first analyte and the second material is a second analyte.
14 . The electronic device of claim 13 , wherein the control electronics are configured to cause the power source to power the laser light source to emit a single frequency of laser light into the waveguide, the single frequency overlapping an absorption spectrum of a compound within the second analyte.
15 . The electronic device of claim 9 , comprising a housing enclosing the power source, the control electronics, the laser light source, and the photonic circuit.