On crystallographic orientation in crystal core optical fibers II: Effects of tapering

Previously reported [Opt. Mater. 32 (2010) 862–867] was the crystallographic orientation of the core phase in a semiconductor optical fiber relative to the fiber axes. In this continuation, the same glass-clad crystalline germanium core optical fibers were tapered and, for the first time to the best of our knowledge, the influence of tapering on the core crystallography is studied and reported. Single crystal X-ray diffraction (SC-XRD) shows that the act of tapering not only modifies the fiber dimension but also re-orients the crystallography of the crystalline core. This can be especially useful to the continued optimization of these crystalline semiconductor core optical fibers and such control over crystal orientation is critical for future fiber-based nonlinear and optoelectronic devices.

► First tapering of glass-clad crystalline germanium core optical fiber. ► Influence of tapering on the crystallographic orientation of core evaluated. ► Tapering shown to re-orient crystallography with respect to the fiber axis. ► Such control can enhance nonlinearities in future crystalline optical fibers.