Proceedings Article | 30 January 2012
Proc. SPIE. 8218, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications XII
KEYWORDS: Optical fibers, Refractive index, Silica, Cladding, Polymers, Fiber lasers, Polymer optical fibers, Fluorine, Polymer thin films, Photorefractive polymers
Polymer claddings with low refractive indices for silica core fibers were developed. Applications include fiber
lasers and transmission of high power lasers in surgery. For many applications, operating fibers under high
temperatures is desirable. In a previous publication, the results of testing polymer cladded silica core fiber at 150°C
for 6400 hours were given, along with 5000 hours of testing polymer films. The results at 150°C were encouraging,
with little additional loss measured. Here we test polymers under more severe conditions, at 270°C, for periods up
to 10 hours. The polymers' cured indices range from 1.374 to 1.397 (at 852 nm). Changes in Young's modulus,
refractive index, yellowing, weight, hardness, strength, and elongation were observed. While these polymers cannot
function at 270°C for extended periods, it is possible to expose them for shorter durations without significant
damage. Some polymer properties actually improved after 4 hours of heating. Fibers clad with such polymers have
been successfully jacketed with extruded materials, and have endured high temperatures for a few minutes. It is
possible that a sensor, fiber laser or other fiber device could function in these temperatures for short periods without
the coating properties changing beyond values required for operation.
