Low-loss and long-length single-mode fibres have been fabricated by the VAD (Vapour phase axial deposition) method. The most important technique was a new torch development in order to form a thick low-loss cladding region in the thin porous preform. The best loss values for the VAD single-mode fibres were 0.35 dB/km at 1.3 µm and 0.2 dB/km at 1.55 µm. The OH absorption loss at 1.39 µm in the fibre was reduced to less than 0.1 dB/km. Moreover it turned out that VAD fibres had less tendency of the loss increase with increasing Δn than MCVD fibres.

The possibility of applying nonlinear optical organic materials to a high speed optical Kerr shutter was investigated. As switching materials, we chose doped PMMA, in which 2, 5-dichloroterephthal-bis [(p-diethylamino) aniline] (SBAC, Symmetrically substituted Benzylidene Aniline) dyes with large χ values were dispersed. The solubilities of the SBAC dyes were increased by controlling their polarity and bulkiness. As the dye concentration was increased, the χ of the doped PMMA increased to as large as 2.61013 esu. In addition, the extinction ratio of the doped PMMA, an important factor in Kerr shutter operation, was improved to 45 dB by investigating polymerization conditions and processes. As a result, optical Kerr shutter operation was observed in a doped polymer system for the first time, and the n2 value of doped PMMA with a χ value of 1.51013 esu was found to be 9.11015 cm2W1.

We have studied the basic optical and physical characteristics of polymeric optical waveguide films with S-shaped waveguides and 45 mirrors applied as multimode optical interconnection components. The core and cladding of the waveguide films were made of deuterated-polymethylmethacrylate (d-PMMA) and UV-cured resin, respectively. We evaluated the insertion losses of the waveguides, the crosstalk and the 45-mirror losses in these waveguide films and demonstrated that they have low propagation loss. The shrinkage and thermal expansion of the polymeric optical waveguide films are also discussed because of the interest in improving module packaging.