Attenuator with improved fabrication consistency
View Patent ↗A method of forming an attenuator on an optical device includes forming a ridge for a waveguide. The ridge is formed in a light-transmitting medium that is positioned on a base. The ridge extends upwards from slab regions of the light-transmitting medium. The method also includes forming trenches in the slab regions of the light-transmitting medium such that the trenches extend through the light-transmitting medium to the base. The trenches are formed such that the ridge is located between the trenches. The method also includes forming a semiconductor in a bottom of each of the trenches and then doping a region of each of the semiconductors.
1. A method of forming an attenuator on an optical device, comprising:
forming a waveguide ridge in a light-transmitting medium, the ridge extending upwards from slab regions of the light-transmitting medium, the light-transmitting medium being positioned on a base;
forming trenches in the slab regions of the light-transmitting medium, the trenches extending through the light-transmitting medium to the base, the ridge being between the trenches;
forming a semiconductor in a bottom of each of the trenches; and
doping a region of each of the semiconductors.
2. The method of claim 1 , wherein the semiconductor in the bottom of each trench contacts the base.
3. The method of claim 1 , wherein forming the semiconductor includes depositing the semiconductor.
4. The method of claim 1 , wherein the semiconductor is a different material from the light-transmitting medium.
5. The method of claim 4 , wherein the semiconductor is polycrystalline while the light-transmitting medium is monocrystalline.
6. The method of claim 5 , wherein the polycrystalline semiconductor is polysilicon and the monocrystalline light-transmitting medium is monocrystalline silicon.
7. The method of claim 1 , wherein the semiconductor is in direct physical contact with a lateral side of the slab region of the light-transmitting medium.
8. The method of claim 1 , wherein a cladding is between the semiconductor and a top of at least one of the slab regions of the light-transmitting medium.
9. The method of claim 8 , wherein the cladding is positioned over the ridge and is in direct physical contact with the light-transmitting medium.
10. The method of claim 8 , wherein the semiconductor is in direct physical contact with a lateral side of the slab region of the light-transmitting medium.
11. The method of claim 1 , wherein doping a region of each of the semiconductors includes forming a doped region that extends through at least one of the semiconductors to the base.
12. The method of claim 1 , wherein doping a region of each of the semiconductors includes forming doped region in the semiconductors and further comprising:
applying electrical energy to the doped regions so as to inject carriers into the waveguide such that a light signal traveling through the waveguide is attenuated.
13. The method of claim 1 , wherein the semiconductors are doped so as to form a PIN junction.
14. The method of claim 1 , wherein a lateral side of each slab region is spaced apart from the ridge.
15. An optical attenuator, comprising:
a waveguide that include a ridge of a light-transmitting medium extending upwards from slab regions of the light-transmitting medium, the light-transmitting medium being positioned on a base;
trenches extending through the slab regions to the base, the ridge being between the trenches;
a contact semiconductor in a bottom of each of the trenches, the contact semiconductor including a doped region,
the contact semiconductor being polycrystalline and the light-transmitting medium being monocrystalline.
16. The attenuator of claim 15 , wherein the contact semiconductors are each in direct physical contact with a lateral side of one of the slab regions of the light-transmitting medium.
17. The attenuator of claim 15 , wherein the contact semiconductor is polysilicon and the light-transmitting medium is monocrystalline silicon.