Research On The Growth Technology Of The Single Crystal Fiber

Single crystal fiber is a novel and high-performance optical materials with a set ofadvantages including anti-electromagnetic, corrosion resistance and good light guiding. Thematerial is always applied to the crystal fiber laser, crystal fiber frequency multiplier,holographic data storage, infrared laser transmission and high temperature detection. As abackground that the application in high-temperature testing, the manufacturing process of thesingle crystal fiber is researched in this paper. The single crystal fiber can measure above1800℃, like the temperature in aircraft, rocket engine and the steel furnace, which can not beaccomplished by the traditional approach. The new method has higher accuracy, resolutionand response speed than the traditional one, even has the advantage of continuousmensurability. As a result, research on the growth process of the high-performance singlecrystal fiber has an essential signification for high temperature testing.Three growth approaches including the edge limit method, capillary curing method andpedestal pulling method are researched. The common laser heated pedestal growth method(LHPG) is one of the pedestal pulling method, which is an approach using the crystal seed togrow the crystal fiber after the crystal rod is melt by high powerful laser. Based on theprinciple of the LHPG, the new program for manufacturing single crystal fiber is proposed, inwhich the ring heat source is designed for hating crystal rod, and the optical system of the ringheat source is simulated by Zemax. The feasibility of the program is theoretical verified. Theother part of this research is the design of controlling the source rod and crystal seed bystepping monitor. As the core of controlling part, STC89C52 can convert the rotating motionof the stepping into the straight-line, making the accurate control with the mechanicalplatform come true, so the speed of the single crystal fiber is controlled. At last, by attemptingto grow theα-Al2O3single crystal fiber, the speed of growing, the length of melting scope andthe influence of the diameter ratio on the performance are analyzed and the best growth conditions of several differentα-Al2O3single crystal fiber are summarized. This resultsprovide the reliable theory basis for high- performance single crystal fiber’s growth, createfacilitation for applying the single crystal fiber to high temperature measuring.