Structural Stability Analysis of a Quartz Fiber Optic Coupler Under Thermal Loading

One of the most difficult barriers in high-lumen, high wattage fiber optic lighting is coupling to light guides efficiently without allowing the high lamp temperature to affect the structural stability of the light guide. Lawrence Berkeley National Laboratory's Lighting Systems Research Group is currently developing a novel fiber optic coupler that will employ a variety of high-wattage electrodeless lamps. The goal of the project is to use an electrodeless lamp in a coupler whose design is based entirely on the principle of total internal reflection, as demonstrated in Figure 1.

In the coupling system showing in Figure 1, an electrodeless lamp built in the quartz coupler guides the light from the lamp to the acrylic fiber optic light guides. A major concern with this design is the structural stability of the material surrounding the lamp, since the extreme heat of lamp could cause most plastic or glass materials to melt or crack. The typical operating temperatures of electrodeless lamps range from 800-900 °C. Many lighting and glass experts recommended quartz as the material of choice fro the coupler because of its resilient thermal properties and ability to transmit visible light efficiently.