In this paper, we present a detailed analysis about the electro-optic (EO) polymer modulators using a full vectorial finite
difference (FVFD) mode solver for an optical waveguide and a finite-element method (FEM) for a microwave electrode.
A detailed discussion has been presented to describe a modulator about performance parameters: VπL, ΔfL with the design parameters, where VπL is the product of the half-wave voltage Vπ and the electrode interaction length L, the parameter ΔfL is the product of the 3 dB optical bandwidth Δf and the electrode interaction length L.
Base on the same two monomers, diphenolic acid (DPA) and isophthaloyl chloride (IPC), three chromophore-containing
nonlinear optical (NLO) polyarylate polymers were prepared. A tricyanofuran (TCF)-acceptor type chromophore group
was in main-chain (mPAR-chr1), side-chain (sPAR-chr1) and side-chain with a 1,1-bis(4-hydroxyphenyl)-1-phenyl-2,2,2-trifluoroethane (BPAPF) group (sPAR-F-chr1), respectively. The obtained polymers were characterized and evaluated by UV-Vis, 1H NMR, DSC and TGA. All the polymers exhibited good electro-optic (EO) activity. The relationship between EO coefficients (r33) and the chromophore concentration of the three polymers were also characterized and discussed. There were no obvious differences found in EO activity between mPAR-chr1 and sPAR-chr1 polyarylates with the same chromophore. The fluorinated block polyarylate sPAR-F-chr1 has the largest r33 value in these three polyarylates which is 52 pm/V at the wavelength of 1310 nm (which is almost twice the r33 value of normal polymers contained the same chormophore at the same content), when the concentration of chromophore 1 is 18wt.%. 85% of the r33 value was retained in the sPAR-F-chr1 after being heated at 85°C for 600 hours. The polymer sPAR-F-chr1, with good solubility, high Tg (above 200 °C) and side functional group at the same time, may probably be a practical NLO material. These properties make the new polyarylates have potential applications in EO devices such as EO modulators and switches.
Organic electro-optic polymer has low dielectric constant and high electro-optic coefficient, which is one of the perfect
materials for making modulators with low loss and high bandwidth. In this paper, we synthesized a novel chromophore
based on the 4-(diethylamino) salicylaldehyde electron donor and the rigid isolated benzyl group. Based on the
innovative chormophore, we designed low loss Mach-Zehnder interference modulators with 3dB bandwidth 50GHz
using tapered waveguides and coplanar waveguide electrodes as well as micro-strip electrodes. Performance parameters
of the modulators were detailed analyzed and two microwave driven electrodes were compared.