Single crystal fibers like those made from sapphire are capable of operating at higher temperatures than conventional
silica-glass-based fibers. This work aims to construct single-crystal optical fiber sensors capable of providing
environmental data in combustion, high-temperature chemical processing, or power generation applications where
temperatures exceed 1000 °C and standard silica fibers cease to provide useful information. Here, we explore the
functionalization of single crystal fibers using methodologies intrinsic to the crystal growth process or with methods
which do not severely reduce their operating temperature range. While operating a laser-heated pedestal growth system
to produce single-crystal optical fibers from rod feedstock, we continuously vary parameters such as fiber diameter to
produce novel single-crystal linear distributed-sensing devices. The spectral characteristics of those modified devices,
along with sensing performance in a high-temperature harsh-environment are reported. Finally, a technique for
increasing the intrinsic Rayleigh backscattering using femtosecond laser irradiation is discussed for temperature sensing
applications.
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