Temperature dynamics in silicon core fibers during CO2 laser processing

Silicon core fibers are a promising candidate for optoelectronic and photonic applications. Fabrication and post-processing of those fibers is thus far done without precise knowledge of the processing temperatures. Here, a simple technique is presented that allows for in-situ temperature monitoring during thermal processing of silicon core fibers. The temperature was probed across the silicon melting point and cooling rates above 3500 degrees C s(-1) were measured. The silicon core was found to be molten at a temperature of 1281 degrees C, more than 100 degrees C below the bulk silicon melting point. This is attributed to stress inbuilt to silicon core fibers during the fabrication process. (c) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement