CONVEX POLYGON-SHAPED ALL-GLASS MULTI-CLAD OPTICAL FIBER ANDMETHOD OF FABRICATION THEREOF

摘要

An all-glass multi-clad polygon-shaped convex optical fiber comprises a core having a core refractive index, a first glass cladding disposed around the core and having a first cladding refractive index that is lower than the core refractive index of the core, and at least a second glass cladding disposed around the first glass cladding and having a second cladding refractive index that is lower than the first cladding refractive index. The first and second claddings each have a convex polygonal cross-section, e.g. octagonal cross-sections. A method for fabricating such an optical fiber comprises the steps of: (i) mechanically machining an all-glass optical fiber preform having a core and a first cladding into an optical fiber preform having a convex polygonal cross-section; and (ii) fusing at least another glass cladding to the optical fiber preform, thereby resulting in the all-glass multi-clad polygon-shaped convex optical fiber. Step (ii) may comprises collapsing a glass tube onto the optical fiber preform for fusing the at least another glass cladding thereto, or may be achieved is achieved by an outside plasma deposition process. In a further step (iii), an external surface of the all-glass multi-clad polygon-shaped convex optical fiber is mechanically rounding off.