Method for making nanocrystalline glass-ceramic fibers

A method of making a glass ceramic material suitable for optoelectronic applications, said method comprising:

• a) preparing a glass composition to yield a precursor glass, doped with at least one selected optically active ion, for a nanocrystalline glass ceramic the precursor glass having a crystallization temperature;
• b) forming the doped precursor glass into a glass cane;
• c) surrounding the glass cane with a chemically inert cladding material to thereby form a clad glass cane having the doped precursor glass as the core;
• d) forming from the clad glass cane an optical component at a temperature above the crystallization temperature of the doped precursor glass;
• and
• e) heat treating at least a portion of the optical component to develop nanocrystals within the doped precursor glass, thereby forming said heat treated portion into a glass ceramic material suitable for optoelectronic applications;
• wherein the glass ceramic material suitable for optelectronic applications is in the form of a clad optical fiber, and
• wherein the glass-ceramic material forms the core of the optical fiber, the core having a CTE in the range of 10-90×10−7/° C., and the cladding having a CTE in the range of 5-70×10−7/° C.