Multi-month thermal aging of electro-optic polymer waveguides: Synthesis, fabrication, and relaxation modeling

Effect of Nanoparticles on the Morphology, Thermal, and Electrical Properties of Low-Density Polyethylene after Thermal Aging

This paper investigates the morphology, thermal, and electrical properties of LDPE (low-density polyethylene)-based nanocomposites after thermal aging. The FTIR (Fourier transform infrared spectroscopy) spectra results show that thermo-oxidative reactions occur in neat LDPE and LDPE/SiO₂ nanocomposites when the aging time is 35 days and in LDPE/MgO nanocomposites when the aging time is 77 days. Specifically, LDPE/MgO nanocomposites delay the appearance of thermo-oxidative reactions, showing anti-thermal aging ability. Furthermore, nanocomposites present lower onset degradation temperature than neat LDPE, showing better thermal stabilization. With regard to the electrical properties, nanocomposites maintain the ability to suppress space charge accumulation after thermal aging. Additionally, in comparison with SiO₂ nanocomposites and neat LDPE, the permittivity of LDPE/MgO nanocomposites changes slightly after thermal aging. It is concluded that LDPE/MgO nanocomposites have better insulation properties than neat LDPE after thermal aging, which may be caused by the interface introduced by the nanoparticles.

Synthesis and characterization of electro-optic polyurethane-imide and fabrication of optical waveguide device

The novel electro-optic (EO) polymers of fluorinated cross-linkable Y-type polyurethane-imides (PUI) were designed and synthesized by polycondensation of second-order non-linear optical azo-based chromophores, phenyl diisocyanate, and aromatic dianhydride. Molecular structural characterization for the resulting polymers was achieved by proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, elemental analysis, and gel permeation chromatography. The resulting polymers exhibited good film-forming properties, high glass transition temperature in the range from 186°C to 198°C and thermal stability up to 300°C, high EO coefficient ( γ33 = 43–60 pm/V) at 1550 nm wavelength, good stabilization of electrically induced chromophore dipole alignment and low optical propagation losses in the range of 1.5–1.7 dB/cm at 1550 nm, which are suitable for the EO modulators. Using the synthesized EO PUI as the active core material and of a fluorinated polyimide as cladding material, we have designed and fabricated the high-performance polymer waveguide Mach-Zehnder EO modulators. Obvious modulation was observed by application of ac voltage signal to the EO modulators.

Demonstration of a high-speed switch with coplanar waveguide electrodes based on electro-optic polymer-clad waveguides

A Mach–Zehnder interferometer type of optic switch with electro-optic polymer-clad waveguides was fabricated with the simple wet-etching procedure, which exhibited low insertion loss and high-speed switching response.

Recent advances in polymer electro-optic modulators

Development of polymer EO modulators.