Fabrication of High Glass Transition Temperature Graded-Index Plastic Optical Fiber: Part 2—Fiber Fabrication and Characterizations

Graded-index plastic optical fiber (GI POF) whose core material consisted of copolymer of 2,2,2-trichloroethyl methacrylate and
N
-cyclohexyl maleimide, and diphenyl sulfide (DPS) as dopant was fabricated by the dopant diffusion coextrusion process, where poly(methyl methacrylate) and polycarbonate were employed as cladding and overcladding material, respectively. The glass transition temperature
Tg
of the core material was set to 115
^°
C by modifying copolymer composition ratio and DPS content. The attenuation of the copolymer-based GI POF was 132 and 330 dB/km at the wavelengths of 660 and 780 nm, respectively. The bandwidths were 1.7 GHz and over 2 GHz for 774 and 654 nm wavelength, respectively. Due to the high numerical aperture of 0.3, the bending loss of the sample fiber consisting of 250 μm core diameter was ca. 0.03 dB under conditions of 180
^°
, 10 mm radius, one time bending. As a result of heat resistance performance evaluation, the attenuation was preserved for more than 2000 h at 100
^°
C. In mechanical property evaluation, the elongation at yield point was ca. 6.7% and tensile load at yield point was 26.2 N (61.0 N/mm
²
), and sufficient flexibility was confirmed by the kink stress test. From these results, the GI POF can be used as high-speed data transmissible lines in automobiles and aircraft, and interconnections inside electric appliances.