The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 1989
Filed:
Dec. 02, 1987
Wolfgang Siefert, Sertoriusring, DE;
Ralf Kersten, Am Konigsberg, DE;
Schott Glaswerke, , DE;
Abstract
Planar single-mode optical waveguides which can conduct light with defined polarisation have so far been embedded in, for example, a cladding made from crystalline LiNbO.sub.3. The crystalline structure of the cladding produces disadvantageous properties such as the fact that the birefringence depends on the geometric profile of the guide, relatively high optical loss, poor fibre coupling, birefringence rigidly fixed by material constants, and a costly manufacturing process. The new process results in an optical waveguide in which both the cladding and the actual guide itself are made of glass with a certain composition, thereby avoiding the disadvantages stated. With the help of a non-isothermal plasma CVD process a light-guiding core region (1) is surrounded on a substrate (4) by cladding layers (2, 2') and a cladding region (3, 3'), the thermal coefficient of longitudinal expansion of the cladding region (3, 3') differing markedly from that of the two homogeneous cladding layers (2, 2'). The core region has either a higher or approximately the same refractive index as the cladding region. Use of the optical waveguide is as a polarisation-receiving or polarising single-mode optical waveguide.