Chris M. Topping

Perfluorocyclobutyl Copolymers for Microphotonics

The copolymerization of aryl bis- and tris-trifluorovinyl other monomers aromatic perfluorocyclobutyl (PFCB) polymers, via thermally initiated stepgrowth cycloaddition chemistry. PFCB polymers and their copolymers enjoya unique combination of attributes well suited for applications in photonic technologies, such as broad tailorability of refractive indices and thermo-optic coefficients, low transmission losses as 1300 and 1550 nm, high thermal, mechanical, and optical stability, and excellent melt and solution processability. Planar PFCB structures lif can be processed by direct micro-transfer molding, which is a first step towards rapid soft-lithographic fabrication of polymer planar lightwave circuits. Copolymerization chemistry and processing parameters and characterization, including thermal (T g ≃120-350°C) and optical properties trefractive indices from 1.443 to 1.308 at 1550 nm, thermooptic coefficients dn/dT-7×10 - 5 K - 1 to -1.5×10 - 6 K - 1 ), birefringence (< 0.003), and temporal stability of refractive index, are described.

Novel perfluorocyclobutyl(PFCB) polymers containing isophorone-derived chromophore for electro-optic [EO] applications

Perfluorocyclobutyl (PFCB) polymers and copolymers have a unique combination of properties well suited for optical applications such as high temperature stability, precisely controlled refractive index, low moisture absorption, excellent melt and solution processability, a variable thermo-optic coefficient, and low transmission loss at 1300 and 1550 nm. Electro-optical devices from polymers of ring locked polyene chromophores are attractive due to their thermal, mechanical, optical and dielectric properties. Polyene chromophores with highest hyperpolarizability are covalently attached to trifluorovinyl aryl ether containing moieties and copolymerized with other monomers. The resulting polymers display imrpoved thermal stability, solubility and good film forming capabilities.

Ultracompact AWG Using Air-Trench Bends With Perfluorocyclobutyl Polymer Waveguides

Using air-trench bends, an ultracompact 8 times 8 arrayed waveguide grating (AWG) demultiplexer (200-GHz channel spacing) for wavelength-division multiplexing (WDM) has been designed and fabricated with perfluorocyclobutyl (PFCB) core and clad co-polymers on a polyimide substrate. Compared to a conventional AWG in the same material system, the air-trench bend AWG shrinks the required chip area by a factor of 20. The decreased size is a factor in reducing the measured thermal shift to -0.012 nm/degC and decreasing the polarization-dependent wavelength shift to 1.3 nm.

Perfluorocyclobutane (PFCB) Polyaryl Ethers for Space-based Applications

Perfluorocyclobutanes represent a relatively new class of partially fluorinated polymers that offer the many of the process advantages of engineering thermoplastics combined with the optical, electrical, thermal, and extreme environment resistant properties of traditional fluoropolymers. Our research has focused on modifications, blends and composites of PFCB’s to enhance their space durability and conductivity to make them suitable for a variety of space based applications. Enhancement of these thermally stable, low a, UV resistant polymers makes them suitable for a variety of space-based applications. Preliminary results indicate that modification, blending, and composite approaches can be used to produce materials with a balance of electrical and thermal conductivity, solar absorbtivity, and AO resistance suitable for a range of space-based applications.