Reduced coating diameter fibers (RCDF) are attractive for increasing fiber density in cables due to their compatibility with the standard 125 μm clad diameter. In this paper, we review recent progress on RCDF and present new modeling and experimental results. We developed microbending models to quantify both the intrinsic and extrinsic microbending sensitivities. Modeling results show that RCDF have lower intrinsic microbending sensitivity but higher extrinsic microbending sensitivity. We made RCDF with coating diameters from 125 to 175 μm. The fibers showed good attenuation on shipping reel, which confirms modeling results on intrinsic microbending. We performed microbending tests on RCDF to quantify their extrinsic microbending sensitivity. The extrinsic microbending results suggest that the microbending sensitivity of RCDF can be reduced by using softer primary coating materials and bend-insensitive fiber designs. We studied the mechanical properties of RCDF including fiber proof strength and puncture resistance. Fiber proof tests showed that fibers with coating diameter greater than 160 μm could pass the 100 kpsi proof test at similar break rates to 242 μm. Fiber puncture resistance could be improved by using better coating material designs. We also conducted a cable trial on a loose tube cable using RCDF with 160 and 170 μm coating diameters. It showed that the RCDF could increase the fiber density by more than 2 times without any microbending and fiber handling issues. Finally, we studied thin 125 μm coated fiber for making low-loss connectors with direct ferrule insertion without stripping the coating, which is promising to reduce fiber breaks and improve connector long term reliability.

We review recent progress on reduced coating diameter fibers for increasing core density for optical interconnect applications. We discuss design considerations on microbending and mechanical reliability and present new experimental results. (C) 2022 The Author(s)

Thin coated single-mode fibers with coating diameters from 125 to 175 μm are fabricated and characterized. The fibers show excellent coating concentricity and attenuation similar to 250 μm coated fiber on shipping reels.

It is challenging to realize both a fully conjugated rigid polymer backbone and high molecular weight at the same time. Previously, we reported a DPP-FT4 polymer with molecular weight up to 30 kDa. A new design and synthesis was required to overcome this limitation. Here, we report the successful synthesis of a conjugated semiconducting polymer with tunable molecular weight over a wide range. Through molecular design and synthesis control, our new polymer can be selectively prepared with number-averaged molecular weight (M-n) ranging from approximately 20 to 100 kDa, realizing both high molecular weight and high solubility at the same time. Four polymers within this range were investigated, with particular emphasis on M-n, of 50 kDa (P2) and 97 kDa (P4). The relationships between molecular weight and polymer properties, molecular packing, and electrical behavior are explored in detail. All the polymers in this series are fully soluble in nonchlorinated solvents at room temperature, which is promising for large-area advanced electronic device applications. The effect of molecular weight on the charge-transport performance of our new polymer was investigated using bottom-gate/top-contact field-effect transistor devices. Stable device characteristics with high on/off ratios up to 10(7) were obtained. Of particular interest is the discovery that the hole mobility of P2 (lower M-n is higher than that of P4 (higher M-n). This is mainly due to morphological manipulation as demonstrated by atomic force microscopy and grazing-incidence X-ray diffraction.

Corning has developed three generations of polymeric organic semiconducting (OSC) materials, each with progressively improved electronic performance and processability. These materials possess excellent solubility, mobility and stability. Stanford University has developed a new polymer dielectric material based on a fluoroelastomer. Combined with Coming's OSC polymers, this enables easy to fabricate transistors with high transconductance, low driving voltage and excellent device stability, even in water.

Radical cations of a soluble rigid tetrathienoacene are capable of forming stable π-dimer dications at ambient temperature when the short backbone becomes extended with conjugated thiophene-2-yl substituents in the α-positions. On the other hand, simple attachment of methyl groups on the α-carbon of the external thiophen-2-yl rings proved sufficient to inhibit the dimerization. Stable radical cations were also exclusively formed for tetrathienoacene derivatives end-capped with bulky TIPS and phenyl substituents.

Radical cations of a soluble rigid tetrathienoacene are capable of forming stable pi-dimer dications at ambient temperature when the short backbone becomes extended with conjugated thiophene-2-yl substituents in the alpha-positions. On the other hand, simple attachment of methyl groups on the alpha-carbon of the external thiophen-2-yl rings proved sufficient to inhibit the dimerization. Stable radical cations were also exclusively formed for tetrathienoacene derivatives end-capped with bulky TIPS and phenyl substituents.

The synthesis and characterization of a fused thiophene-diketopyrrolopyrrole based semiconducting polymer PTDPPTFT4 is presented. A number of synthetic challenges have been overcome in the development of a practical scalable synthesis. Characterization by Gel Permeation Chromatography (GPC) over a range of temperatures has revealed the tendency of this polymer to aggregate even at elevated temperatures and confirmed that the molecular weight values obtained are for nonaggregated material. This polymer meets a number of important requirements for potential industrial applications, such as scalable synthesis, solubility in industrially suitable solvents, and material stability and processability into stable high performance thin film transistor devices. Computational modeling has been used to help explain the structure property relationships contributing to the high performance. Grazing incidence X-ray of the thin films showed out of plane lamellar packing and in plane pi-pi stacking, both good indicators of a preferentially oriented thin film, desirable for high charge carrier mobility. Hole mobilities in excess of 2 cm(2)/V.s, on/off ratio of >10(6), and threshold voltage <2 V have been achieved.