Advances in low index polymer cladding materials

Low index polymer claddings were developed and tested for use with silica core fibers. Polymers with varying indices of refraction were developed, so that numerical apertures useful for multiple applications were produced. High transmission over a wide wavelength range was obtained, both for films and for clad fibers. A refractive index as low as 1.363 was achieved, which results in a numerical aperture of 0.50 (at 852 nm) when used in cladding silica cores. Results for fibers clad with 1.373 index material under high temperatures (150 °C) show that worst case change in loss was within 0.084 dB, even over a time frame of 6400 hours.