A manual acupuncture treatment attenuates common cold and its symptoms: a case series report from South Korea.

OBJECTIVE: To investigate beneficial effects of manual acupuncture on common cold periods and its symptoms depended on the difference onset time of common cold, within 36 h or over than that. To prove effects of manual acupuncture on common cold, a retrospective chart review was conducted. METHODS: Chart data for patients with common cold who were treated with only manual acupuncture with fulfilling Jackson scales and satisfaction at the end of each treatment were collected via multi-centers of Oriental hospitals, Oriental medicine clinics and covalent hospital in South Korea. Totally 187 patients were divided into two groups, Group Ⅰ (115 patients, within 36 h) and Group Ⅱ (72 patients, onset time of cold over than 36 h). Finally 120 patients were observed until entire resolution of cold symptoms. RESULTS: Group Ⅰ showed significant decreases themediandurationsofcompletelyrecovery (3 days; 95% CI 3.0-4.0) as compared with Group Ⅱ (6 days; 95% CI 4.0-7.0, P < 0.001). The manual acupuncture beneficially worked for reduction rate of common cold symptoms by 50% after initial treatment, decreased cold symptoms, and reduced cold duration. CONCLUSION: Manual acupuncture beneficially affected common cold and its symptoms. Moreover it is more susceptibility on the early time of onset cold.

Enhanced four-wave-mixing effects by large group indices of one-dimensional silicon photonic crystal waveguides.

Enhanced four-wave-mixing (FWM) effects have been observed with the help of large group-indices near the band edges in one-dimensional (1-D) silicon photonic crystal waveguides (Si PhCWs). A significant increase of the FWM conversion efficiency of about 17 dB was measured near the transmission band edge of the 1-D PhCW through an approximate 3.2 times increase of the group index from 8 to 24 with respect to the central transmission band region despite a large group-velocity dispersion. Numerical analyses based on the coupled-mode equations for the degenerated FWM process describe the experimentally measured results well. Our results indicate that the 1-D PhCWs are good candidates for large group-index enhanced nonlinearity devices even without having any special dispersion engineering.

Low-voltage high-performance silicon photonic devices and photonic integrated circuits operating up to 30 Gb/s.

We present high performance silicon photonic circuits (PICs) defined for off-chip or on-chip photonic interconnects, where PN depletion Mach-Zehnder modulators and evanescent-coupled waveguide Ge-on-Si photodetectors were monolithically integrated on an SOI wafer with CMOS-compatible process. The fabricated silicon PIC(off-chip) for off-chip optical interconnects showed operation up to 30 Gb/s. Under differential drive of low-voltage 1.2 V(pp), the integrated 1 mm-phase-shifter modulator in the PIC(off-chip) demonstrated an extinction ratio (ER) of 10.5dB for 12.5 Gb/s, an ER of 9.1dB for 20 Gb/s, and an ER of 7.2 dB for 30 Gb/s operation, without adoption of travelling-wave electrodes. The device showed the modulation efficiency of V(π)L(π) ~1.59 Vcm, and the phase-shifter loss of 3.2 dB/mm for maximum optical transmission. The Ge photodetector, which allows simpler integration process based on reduced pressure chemical vapor deposition exhibited operation over 30 Gb/s with a low dark current of 700 nA at -1V. The fabricated silicon PIC(intra-chip) for on-chip (intra-chip) photonic interconnects, where the monolithically integrated modulator and Ge photodetector were connected by a silicon waveguide on the same chip, showed on-chip data transmissions up to 20 Gb/s, indicating potential application in future silicon on-chip optical network. We also report the performance of the hybrid silicon electronic-photonic IC (EPIC), where a PIC(intra-chip) chip and 0.13µm CMOS interface IC chips were hybrid-integrated.

Adjusting resonant wavelengths and spectral shapes of ring resonators using a cladding SiN layer or KOH solution.

It is shown that the resonant frequencies and the transmission spectra of ring resonators can be adjusted by depositing or etching the cladding nitride layer on the ring waveguide without introducing an extra loss or extra variations of channel spacing. The cladding nitride layer increases the minimum width of the gap in the coupling region to larger than 150nm which makes it possible to consider photolithography instead of E-beam lithography for the typical design rule of ring filters. KOH silicon etching can also adjust not only the resonance frequencies but also coupling coefficients with a small sacrifice of guiding loss.

Low bending loss metal waveguide embedded in a free-standing multilayered polymer film.

Very low vertical bending loss is demonstrated in a flexible metal waveguide. The waveguide consists of an 8 nm-thick and 68 mm-long Ag strip embedded in a free-standing multilayered low-loss polymer film. The polymer film is composed of a 10 microm-thick inner cladding with a refractive index of 1.524, and a pair of 20 microm-thick outer claddings which both have a refractive index of 1.514, resulting in a total thickness of 50 microm. The measured vertical bending loss is lower than 0.3 dB/180 masculine at a wavelength of 1310 nm for the bending radii down to 2 mm.

Sub-dB/cm propagation loss in silver stripe waveguides.

We demonstrate sub-dB/cm propagation losses in polymer-based silver stripe waveguides at the wavelength of 1.31 microm. The silver stripe waveguides were fabricated in a low-loss fluorinated polymer clad. To form uniform metal stripe patterns, which are essential for reducing propagation loss, we developed a lift-off process using double layers of photoresist and SiNx. A propagation loss of less than 1.0 dB/cm was obtained with the 11- nm-thick silver stripes in the width range of 1.5 - 4.5 microm. A coupling loss of approximately 1.0 dB with a polarization maintaining single mode fiber was achieved for a width of 4.5 microm. For a width of 2.0 microm, we recorded a minimum propagation loss of 0.4 dB/cm, which is comparable with that of dielectric multi-mode waveguides.

Enhancing alignment tolerance of silicon waveguide by using a wide grating coupler.

We fabricate a 20 um wide grating coupler for a single-mode thermally-expanded-core (TEC) fiber, in order to enhance positional tolerance in alignment. The minimal coupling loss is measured at 5 dB per facet and the optical 3 dB bandwidth is measured at 40 nm. The 3 dB alignment tolerance is measured at +-7.5 microm in horizontal direction and +290 microm in vertical direction. The 1 dB alignment tolerance is measured at +-4.2 microm in horizontal direction and +125 microm in vertical direction. The alignment tolerance is enhanced twice in horizontal direction and four times in vertical direction, compared with the coupling of a standard single-mode fiber to a standard 10 microm wide grating coupler which is also fabricated in this experiment.

Controlling temperature dependence of silicon waveguide using slot structure.

We show that the temperature dependence of a silicon waveguide can be controlled well by using a slot waveguide structure filled with a polymer material. Without a slot, the amount of temperature-dependent wavelength shift for TE mode of a silicon waveguide ring resonator is very slightly reduced from 77 pm/ degrees C to 66 pm/ degrees C by using a polymer (WIR30-490) upper cladding instead of air upper cladding. With a slot filled with the same polymer, however, the reduction of the temperature dependence is improved by a pronounced amount and can be controlled down to -2 pm/ degrees C by adjusting several variables of the slot structure, such as the width of the slot between the pair of silicon wires, the width of the silicon wire pair, and the height of the silicon slab in our experiment. This measurement proves that a reduction in temperature dependence can be improved about 8 times more by using the slot structure.