Abstract: Sol-gel methods, apparatus and compositions for cladding optical fiber cores provide optical fibers, including single crystal optical fiber cores with polycrystalline cladding, having improved performance in a variety of applications, such as fiber lasers.

Abstract: Disclosed are apparatuses and methods for growing thin crystal fibers via optical heating. The apparatuses may include and the methods may employ a source of optical energy for heating a source material to form a molten zone of melted source material, an upper fiber guide for pulling a growing crystal fiber along a defined translational axis away from the molten zone, and a lower feed guide for pushing additional source material along a defined translational axis towards the molten zone. For certain such apparatuses and the methods that employ them, the lower feed guide's translational axis and upper fiber guide's translational axis are substantially aligned vertically and axially so as to horizontally locate the source material in the path of optical energy emitted from the optical energy source, in some cases to within a horizontal tolerance of about 5 ?m.

Abstract: A laser heated pedestal growth system for growing a periodically poled, single crystal rod having domain interfaces substantially parallel to the rod's long axis. Suitable crystalline ferroelectric feed materials have a Curie temperature no greater than ˜200° C. below its melting point and include Lithium Niobate and MgO doped Lithium Niobate.

Abstract: A post-growth optical afterheater system includes an appropriate choice of optical heat source for the single crystal material to be heated, a power adjustment module for controlling the optical power heating the crystal, and suitable focusing optics to focus the heating beam onto the crystal. The heat source may be a laser of appropriate wavelength or an incoherent source of sufficient power. In one embodiment, the power adjustment module is an optical attenuator, either of crossed-polarizer design or of intersecting wire grids. The focusing optics may be refractive, reflective, or catadioptric, depending on factors such as diameter, cost target, and space available in the crystal growth apparatus.