Single-crystal-fiber-based distributed ultra-high temperature (1600℃) sensing system

The pursuit of enhanced performance in optical-fiber-based distributed temperature sensing (DTS)—including higher resolution, extended range, and faster acquisition—is a central focus of ongoing research. In this work, we report a new record for the high-temperature limit in a Raman DTS system. We selected single-crystal YAG fiber over sapphire due to its superior Raman gain, despite its marginally lower melting point (1970°C vs. 2054°C). Through two key innovations—protecting the fiber with an Argon gas encapsulation and utilizing a shorter laser wavelength—we elevated the system's maximum measurable temperature from 1400°C to 1600°C. Simultaneously, we achieved a temperature resolution of 0.07% with a 1-second averaging time. Efforts to push the temperature limit even further are currently underway. This achievement holds significant promise for applications in extreme environments, such as those found in the aerospace and energy sectors.