Design and analysis of a low loss and large-tolerance optical interface for large-area optical waveguides

An alternative interface structure design of a large-area optical waveguide for a large-area optical printed circuit board using a step-out fabrication technique is proposed. To investigate the misalignment tolerances and coupling excess losses, we simulated and compared our proposed structure to a typical straight core structure. As a result, the proposed structure was found to significantly improve the misalignment tolerance by more than 2 times and successfully conduct a data-link based on large area optical waveguide of 50 cm ×?50 cm.     

Tributyltin Hydride-Induced Free Radical Deoxygenation of the Cyclic Thionocarbonates of Threo-2,3-Dihydroxy Esters and Ketones

Abstract: A practical and enantiospecific method for the synthesis of optically pure β-hydroxy esters and ketones is described. The key reaction is free radical deoxygenation of the cyclic thionocarbonates of threo-2,3-dihydroxy esters and ketones with tributyltin hydride.     

Cyanopeptoline CB071: a cyclic depsipeptide isolated from the freshwater cyanobacterium Aphanocapsa sp

Cyanopeptolin CB071 (1), a trypsin inhibitor, was isolated from the freshwater cyanobacterium Aphanocapsa sp. Its complete structure was determined by detailed NMR spectroscopy and MS analyses, along with chemical reactions. The compound showed inhibition of trypsin at a concentration of IC50=2.5 microM.     

Phorbasins G--I: three new diterpenoids from the sponge Phorbas gukulensis

Phorbasins G--I (1--3) were isolated from the sponge Phorbas gukulensis collected from Gagu-Do, Korea. The complete structure of the compounds was determined by NMR and MS spectroscopy, along with chemical reaction. Phorbasin G (1) was found to be a diterpene possessing a taurine residue.     

Hierarchical Self-Assembled Photo-Responsive Tubisomes from a Cyclic Peptide-Bridged Amphiphilic Block Copolymer

Typically, the morphologies of the self-assembled nanostructures from block copolymers are limited to spherical micelles, wormlike micelles and vesicles. Now, a new generation of materials with unique shape and structures, cylindrical soft matter particles (tubisomes), are obtained from the hierarchical self-assembly of cyclic peptide-bridged amphiphilic diblock copolymers. The capacity of obtained photo-responsive tubisomes as potential drug carriers is evaluated. The supramolecular tubisomes pave an alternative way for fabricating polymeric tubular structures, and will expand the toolbox for the rational design of functional hierarchical nanostructures.     

Evidence of multiple pathways capable of emitting peroxyoxalate chemiluminescence using a charge coupled device spectrometer

Peroxyoxalate chemiluminescence (PO-CL) spectra obtained simultaneously and continuously using a CCD spectrometer provide evidence of the complexity of PO-CL reactions.     

Raman scattering studies of (GaP)n/(InP)n (n = 1, 1.7, 2) short‐period superlattice structures

We report Raman scattering from (GaP)_n/(InP)_n (n = 1, 1.7, 2) short‐period superlattice (SPS) structures to study the effect of lateral composition modulation (LCM) on the behavior of optical phonons. Cross‐sectional transmission electron microscope images revealed that LCM was formed with complex pattern in the n = 1.7 and n = 2 samples grown at 490 °C. Interestingly, both the InP‐ and the GaP‐like longitudinal optical (LO) phonon energies increased systematically as the number of monolayers was increased from n = 1 to n = 2. A significant broadening of the phonon line shapes was also observed for the n = 1.7 and n = 2 samples. In contrast, for samples grown at 425 °C, both the increase of the LO phonon energies and the broadening of the phonon line shapes were observed only when n = 1.7. Our results demonstrate that the optical phonons in the (GaP)_n/(InP)_n SPS structures are significantly affected in the occurrence of LCM related to the growth temperature and the number of monolayers.Copyright © 2009 John Wiley & Sons, Ltd.     

Blue and infrared cathodoluminescence induced by carbon-irradiation in SrTiO3 single crystal

We show that blue-CL can be induced in SrTiO₃ single crystal at room temperature by irradiating it with 60 KeV carbon ion (C⁻) beam. An infrared CL-emission is induced simultaneously. Transmission electron microscopy (TEM) measurement exhibits an 200 nm thick surface layer formed by the C⁻ irradiation. We show that the emitting region can be patterned into any desired shape by fabricating the STO surface using Pt-based micro-lithography technique.     

Polymer waveguide with integrated reflector mirrors for an inter-chip link system

A polymer waveguide with integrated reflector mirrors is presented for an inter-chip link system. The cost-effective and repeatable technology for the integration of a polymer multimode waveguide and out-of-plane 45° reflector mirrors was developed for optical coupling between the light-sources and the light-detectors. This method enabled us to fabricate the waveguides and 45° reflector mirrors using a one-shot embossing process for inexpensive mass production. The optical inter-chip link system consisted of a metal optical bench, a module printed circuit board (PCB), a driver/receiver IC, a vertical-cavity surface-emitting laser (VCSEL)/photo-detector (PD) array, and an optical waveguide composed of integrated reflector mirrors. The presented data transfer measurements of the optical inter-chip link system are shown to be successful at a data rate of 5 Gb/s.