Toshikuni Kaino

Absorption Losses of Low Loss Plastic Optical Fibers

Absorption loss factors such as the high harmonics of molecular vibrational absorption and the electronic transitional absorption of plastic optical fibers are analyzed and it is quantitatively revealed that the high harmonics of the CH vibrational absorption of core material are the most significant constituents causing the loss in PMMA-core fibers. OH vibrational absorption due to contained water, on the other hand, has the most effect on loss in perdeuterated PMMA (P(MMA-d8)) core fibers. Visible wavelengths (570 and 650 nm) are preferable for optical signal transmission for PMMA- or P(MMA-d8)-core fibers.

Low-loss polystyrene core-optical fibers

Low‐loss plastic optical fibers (POF) have been prepared with the attenuation loss of 114 dB/km at the wavelength of 670 nm employing polystylene core and ethylene‐vinylacetate copolymer cladding. The POF can allow the use for short‐distance optical signal transmission. The theoretical loss limit of polystylene core POF is calculated to be 70 dB/km at 670 nm.

Influence of water absorption on plastic optical fibers

The influence of absorbed water on the attenuation loss of plastic optical fibers (POFs) is discussed. By lowering the POF loss, absorbed water becomes the significant constituent for the loss of POFs. The degree of loss increment due to water absorption depends on the relative humidity of the environment where the POFs exist. A low-loss deuterated PMMA core POF is thought to be suitable for use as a visible-wavelength-region optical signal transmission medium. A deuterated polystyrene core POF can be used as a near-IR transmission medium.

Plastic optical fibers

Characteristics of plastic optical fibers (POF)s, i.e., handling ease because of their good ductility, splicing ease to each other and to light sources because of their large fiber diameter and high numerical aperture, processability, and high flexibility notwithstanding their larger fiber diameters, have attracted much attention. They are expected to be applied as a short distance optical signal transmission medium for certain kinds of computer-toterminal data links such as in office automation systems. Polymers for POF application should be as transparent as possible and therefore they should be low in scattering loss, and their refractive index should be controllable to fabricated fiber structures. In this paper, POF optical transparency, light scattering, optical bandwidth, and refractive index control are discussed in detail along with polymer loss limit