RESUMEN
An electro-optic (EO) polymer waveguide using an ultra-thin silicon hybrid has been designed and fabricated. The silicon core has the thickness of 50 nm and a width of 5 µm. The waveguide was completed after covering the cladding with the high temperature stable EO polymer. We have demonstrated a low half-wavelength voltage of 0.9 V at the wavelength of 1.55 µm by using a Mach-Zehnder interference modulator with TM mode operation. The measured modulation corresponded to an effective in-device EO coefficient of 165 pm/V. By utilizing the traveling-wave electrode on the modulator the high-frequency response was tested up to 40 GHz. The 3 dB modulation bandwidth was measured to be 23 GHz. In addition, the high frequency sideband spectral measurement revealed that a linear response of the modulation index against the RF power was confirmed up to 40 GHz signal.
RESUMEN
We report on volume holographic recording at a wavelength of 532 nm in photopolymerizable polymer nanocomposites that are incorporated with new hyperbranched polymers (HBPs) acting as transporting organic nanoparticles. Since HBPs possess an ultrahigh index of refraction of 1.82 due to the inclusion of triazine and aromatic ring units, high-contrast transmission volume holographic gratings with refractive index modulation amplitudes as large as 2.2×10(-2) are recorded. This value enables us to realize a 10 µm thick transmission volume grating with the diffraction efficiency near 100% in the green.
RESUMEN
An electro-optic (EO) modulator using a TiO2 slot hybrid waveguide has been designed and fabricated. Optical mode calculations revealed that the mode was primarily confined within the slots when using a double-slot configuration, thus achieving a high EO activity experimentally. The TiO2 slots also acted as an important barrier to induce an enhanced DC field during the poling of the EO polymer and the driving of the EO modulator. The hybrid phase modulator exhibited a driving voltage (Vπ) of 1.6â V at 1550â nm, which can be further reduced to 0.8â V in a 1â cm-long push-pull Mach-Zehnder interferometer (MZI) structure. The modulator demonstrated a low propagation loss of 5â dB/cm and a relatively high end-fire coupling efficiency.
RESUMEN
In this work, an electro-optic (EO) ring resonator modulator was designed and fabricated in a waveguide consisting of a titanium dioxide (TiO)2 core, silicon dioxide (SiO2) buffer layer, EO polymer claddings, and electrodes. By optimizing the thickness of the TiO2 and SiO2layers, the modulator could satisfy the single-mode requirement; furthermore 52.5% TM mode was confined in the active EO polymer layers. The designed modulator could also pole the EO polymer effectively regardless of its resistivity. Therefore, the EO modulator was observed to show a high resonance wavelength shift of 2.25 × 10(-2) nm/V. The intensity modulation at 1550 nm showed a Vp-p = 1.9 V for a 3dB distinction ratio.
RESUMEN
High water-soluble hyperbranched poly(styrene) (HPS) polymers carrying stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals, HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), were prepared in ca. 60% introducing yield. HPS-N-TEMPO and HPS-Im-TEMPO were determined to be nearly spherical shapes of the diameter of 2.4 +/- 0.6 and 2.2 +/- 0.6 nm, respectively, by transmission electron microscope (TEM) images. The values of water-proton relaxivity, r(1), at 25 MHz, 0.59 T, and 25 degrees C were 6.0, 5.2, and 14 mM(-1) sec(-1) for HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), respectively. The spin-lattice relaxation time (T(1))-weighted images in phantom were also observed.
