Layered glass structures
Layered glass structures and fabrication methods are described. The methods include depositing soot on a dense glass substrate to form a composite structure and sintering the composite structure to form a layered glass structure. The dense glass substrate may be derived from an optical fiber preform that has been modified to include a planar surface. The composite structure may include one or more soot layers. The layered glass structure may be formed by combining multiple composite structures to form a stack, followed by sintering and fusing the stack. The layered glass structure may further be heated to softening and drawn to control linear dimensions. The layered glass structure or drawn layered glass structure may be configured as a planar waveguide.
1. A method for making a planar layered glass structure comprising:
forming a composite structure, said composite structure including a first soot layer on a planar surface of a dense glass substrate, said first soot layer having a thickness of at least 100 μm;
preparing a layered glass structure from said composite structure, said preparing including consolidating said first soot layer; and
drawing said layered glass structure along a direction of drawing to form a drawn layered glass structure, said drawn layered glass structure having a first dimension in said direction of drawing and a second dimension in a direction transverse to said direction of drawing, the ratio of said first dimension to said second dimension being at least 3.0, said consolidated first soot layer having a thickness in said drawn layered glass structure of at least 10μm.
2. The method of claim 1 , wherein said first soot layer has a thickness of at least 1 mm.
3. The method of claim 1 , wherein said first soot layer has a thickness in the range from 150 μm to 4 mm.
4. The method of claim 1 , wherein said dense glass substrate is formed from an optical fiber preform.
5. The method of claim 1 , wherein said dense glass substrate further includes a rounded surface.
6. The method of claim 1 , wherein said consolidating includes heating said first soot layer to a temperature of at least 1000 ° C.
7. The method of claim 6 , wherein said heating includes exposing said first soot layer to a laser.
8. The method of claim 1 , wherein said consolidated first soot layer has a thickness in said drawn layered glass structure in the range from 100 μm to 25 mm.
9. The method of claim 1 , wherein said consolidated first soot layer has an average surface roughness R a of less than 0.50 nm over an area of at least 1 mm 2 .
10. The method of claim 1 , wherein said drawing increases a linear dimension of said layered glass structure by 10% - 500%.
11. The method of claim 1 , wherein said drawn layered glass structure has a length in the range from 0.1 m - 5.0 m.
12. The method of claim 1 , wherein said ratio of said first dimension to said second dimension is at least 10.
13. The method of claim 1 , wherein said drawn layered glass structure has attenuation less than 0.5 dB/m over the wavelength range from 1000 nm - 1300 nm.
14. The method of claim 1 , wherein said dense glass substrate comprises a silica-based glass.
15. The method of claim 14 , wherein said first soot layer comprises a silica-based glass with a dopant.
16. The method of claim 15 , wherein said dopant includes a rare earth element.
17. The method of claim 16 , wherein said silica-based glass with dopant includes Al, Ge, or Ti.