Intrinsic Transmission Loss of Polycarbonate Core Optical Fiber

Intrinsic transmission loss of polycarbonate (bisphenol A-type) optical fiber (PC-POF) was experimentally determined by investigating three intrinsic loss factors: electronic transition absorption (ETA), molecular vibration absorption (MVA) and light scattering caused by thermal dielectric fluctuation. The intrinsic transmission losses for optical windows are 224 dB/km at 764 nm and approx. 166 dB/km at 650-656 nm. The intrinsic ETA loss is large in the region of short wavelength, hence it is suggested that the PC-POF yellows for white light transmission. The optical anisotropic parameter of polarizability for PC is much larger than that of polymethylmethacrylate (PMMA). The intrinsic scattering loss of PC-POF results almost entirely from the anisotropic scattering caused by the strong optical anisotropy of this polymer. Present transmission loss of PC-POF is much larger than the estimated intrinsic transmission loss because of the large excess loss arising from extrinsic loss factors. The PC-POF has the potential for low transmission loss equal to that of the PMMA-POF, if it is optically purified.