High purity fused silica fiber offers low attenuation and broad spectral transmission. When this fiber is used in imaging sensors, greater information may be transmitted over longer lengths when compared to conventional silicate fibers used in such imaging devices as endoscopes and boroscopes. Heretofore, imaging devices made with fused silica have been limited by small size and poor flexibility. Two imagescopes have been fabricated from two types of high purity glass core/glass clad fused silica fiber providing 8 linepairs per millimeter resolution over 4.6 m length with a 3 mm2 viewing area. Bend radius without loss is less than 2 cm since the loose fibers are fixed only at the ends. Transmission range is from 300 nm to 1100 nm, with attenuation increasing exponentially as a function of wavelength. This is attributed to evanescent tunneling loss through the cladding. Transmission, bend loss, and attenuation were determined for the two fused silica imagescopes and a standard multifiber imagescope.
"Optical Performance Of A Fused Silica Flexible Imaging Device", Proc. SPIE 0838, Fiber Optic and Laser Sensors V, (23 March 1988); doi: 10.1117/12.942537; https://doi.org/10.1117/12.942537