Optical waveguide and method of manufacture thereof
An optical waveguide includes a cladding layer, a Si layer, a REO layer, and a cap layer. The REO layer is made of a single-crystal rare earth oxide, and is formed on the Si layer. The cap layer is formed on the REO layer. The cap layer may be made of a material transparent to light to be guided. The cap layer has a stripe shape extending in a direction in which light is guided.
1 . An optical waveguide comprising:
a cladding layer;
a Si layer made of single-crystal Si and on the cladding layer;
a rare earth oxide (REO) layer made of a single-crystal rare earth oxide and disposed on the Si layer; and
a stripe-shaped cap layer on the REO layer and extending in a direction in which light is guided,
wherein
a width of the stripe-shaped cap layer is in a range of 2.45 μm to 3.0 μm, and
a leakage loss of guided light with a wavelength of 1462 nm is not more than 4.96 dB/cm.
2 . The optical waveguide according to claim 1 , wherein a center of a mode of light to be guided is in a vicinity of an interface between the Si layer and the REO layer in a region where the stripe-shaped cap layer overlaps the Si layer and the REO layer.
3 . The optical waveguide according to claim 1 , wherein the stripe-shaped cap layer is made of SiN or Si.
4 . The optical waveguide according to claim 3 , wherein the cladding layer is made of a silicon oxide.
5 . The optical waveguide according to claim 4 , wherein a center of a mode of light to be guided is in a vicinity of an interface between the Si layer and the REO layer in a region where the stripe-shaped cap layer overlaps the Si layer and the REO layer.
6 . The optical waveguide according to claim 3 , wherein a center of a mode of light to be guided is in a vicinity of an interface between the Si layer and the REO layer in a region where the stripe-shaped cap layer overlaps the Si layer and the REO layer.
7 . The optical waveguide according to claim 1 , wherein the cladding layer is made of a silicon oxide.
8 . The optical waveguide according to claim 7 , wherein a center of a mode of light to be guided is in a vicinity of an interface between the Si layer and the REO layer in a region where the stripe-shaped cap layer overlaps the Si layer and the REO layer.
9 . The optical waveguide according to claim 1 , wherein the REO layer is made of (Er x Gd 1-x ) 2 O 3 .
10 . The optical waveguide according to claim 1 , wherein a width of the cladding layer is in a range of 0.5 μm to 3 μm.
11 . The optical waveguide according to claim 1 , wherein:
the width of the stripe-shaped cap layer is 2.45 μm, and
the leakage loss of the guided light with the wavelength of 1462 nm is not more than 0.37 dB/cm.
12 . A method of manufacturing an optical waveguide, the method comprising:
forming a Si layer made of single-crystal Si over a cladding layer;
forming a rare earth oxide (REO) layer contacting the Si layer, the REO layer being made of a single-crystal rare earth oxide; and
depositing a cap layer over the REO layer; and
patterning the cap layer to form a stripe-shaped cap layer on the REO layer and extending in a direction in which light is guided,
wherein:
a width of the stripe-shaped cap layer is in a range of 2.45 μm to 3.0 μm, and
a leakage loss of guided light with a wavelength of 1462 nm is not more than 4.96 dB/cm.
13 . The method according to claim 12 , wherein forming the REO layer comprises epitaxially growing the REO layer on the Si layer.
14 . The method according to claim 12 , wherein a center of a mode of light to be guided is in a vicinity of an interface between the Si layer and the REO layer in a region where the cap layer overlaps the Si layer and the REO layer.
15 . The method according to claim 12 , wherein the cap layer is made of SiN or Si.
16 . The method according to claim 12 , wherein the cladding layer is made of a silicon oxide.
17 . The method according to claim 12 , wherein the REO layer is made of (Er x Gd 1-x ) 2 O 3 .
18 . The method according to claim 12 , wherein a width of the cladding layer is in a range of 0.5 μm to 3 μm.
19 . The method according to claim 12 , wherein:
the width of the stripe-shaped cap layer is 2.45 μm, and
the leakage loss of guided light with the wavelength of 1462 nm is not more than 0.37 dB/cm.