The status of advanced nonlinear optical materials is reviewed with regard to the requirements implied by their respective applications. Although many functions utilizing nonlinear optical (NLO) materials have been demonstrated in research laboratories, only a few components have found a place in real systems. While this is partly due to a lack of product development effort, the performance of the materials is not adequate in other cases. 111-V based semiconductors show promise for a broad penetration of the field of signal processing for telecommunications and data processing. Linear and nonlinear optical polymers may be applied in assembly and interconnection and in small to medium sized switching matrices. As a prerequisite the anticipated performance has to be achieved, and stability to be demonstrated. Manufacturing maturity is approached by inorganic ferroelectrics, LiNbO, being the most prominent example.

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Several new glass fiber production processes have been studied in the past for low-cost production. Although some of them are still being considered for overcladding, mechanically shaped preforms (MSP) have been demonstrated to be the only remaining candidates to combine economic non CVD processing and low loss, with a published value of 0.63 dB/km and a size of 30 fkm/preform [l]. Improved processing has now resulted in a minimum loss of 0.27 dB/km at 1550 nm. Preforms capable of yielding 150 fkm have been produced. Although already considerably improved, reboiling during preform stretching and fiber pulling is identified as the last remaining problem of the process.

A process has been developed for the mechanical shaping of silica fibre preforms. Porous preforms are shaped from prefabricated powders and transfered to glass rods by thermal treatment. Drawn fibers now have attenuations of 1 dB /km and an OH absorption of 0.5 dB /km at 1380 nm. Both single and multimode fibres have been produced.