We have designed and built a fiber growth apparatus to produce high-optical-quality single-crystal fibers. The growth apparatus uses the laser heated miniature pedestal growth technique and employs novel electronic control, mechanical, and optical systems. Figure 1 schematically illustrates miniature pedestal growth of a single-crystal fiber. A CO2 laser, emitting 10.6-μm radiation, provides a controlled tightly focusable heat source to melt the refractory material. In our apparatus the optical system focuses the laser beam onto the fiber in a 380° axially symmetric distribution as shown in Fig. 2. This symmetric irradiance prevents cold spots in the growth zone. Growth proceeds by simultaneous upward translation of the seed and source rods with a molten zone positioned between them.
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