High-performance Ge/Si electro-absorption optical modulator up to 85°C and its highly efficient photodetector operation.

We studied a high-speed Ge/Si electro-absorption optical modulator (EAM) evanescently coupled with a Si waveguide of a lateral p-n junction for a high-bandwidth optical interconnect over a wide range of temperatures from 25 °C to 85 °C. We demonstrated 56 Gbps high-speed operation at temperatures up to 85 °C. From the photoluminescence spectra, we confirmed that the bandgap energy dependence on temperature is relatively small, which is consistent with the shift in the operation wavelengths with increasing temperature for a Ge/Si EAM.

Spontaneous reduction of iron(III)porphyrin to iron(II)porphyrin-CO complex in mouse circulation.

Iron(II/III)porphyrin/cyclodextrin inclusion complexes serve as hemoprotein models . Here we showed the iron(III)porphyrin complex to be spontaneously reduced to its iron(II) state in mouse circulation. The reduced complex bound endogenous CO from carboxyhemoglobin, which was followed by urinary excretion.

Modulation bandwidth improvement of III-V/Si hybrid MOS optical modulator by reducing parasitic capacitance.

In this work, we numerically and experimentally examined the impact of parasitic capacitance on the modulation bandwidth of a III-V/Si hybrid metal-oxide-semiconductor (MOS) optical modulator. The numerical analysis revealed that the parasitic capacitance between the III-V membrane and the Si slab should be considered to achieve high-speed modulation, particularly in the case of a thick gate oxide. We also fabricated a high-speed InGaAsP/Si hybrid MOS optical modulator with a low capacitance using a SiO-embedded Si waveguide.

High-efficiency and high-speed narrow-width MOS capacitor-type Si optical modulator with TM mode excitation.

We developed a high-speed and high-efficiency narrow-width metal-oxide-semiconductor (MOS) capacitor-type Si optical modulator (Si-MOD) by applying TM optical mode excitation. We designed and fabricated an optical-mode-converter structure from TE to TM mode. Even in the case of a 200-nm width, the Si MOS-MOD showed high-modulation efficiency in TM mode (about 0.

Taperless Si hybrid optical phase shifter based on a metal-oxide-semiconductor capacitor using an ultrathin InP membrane.

We propose a III-V/Si hybrid metal-oxide-semiconductor (MOS) optical phase shifter using an ultrathin InP membrane, which allows us to eliminate the III-V taper required for mode conversion between Si and hybrid waveguides. We numerically revealed that thinning a III-V membrane can reduce the insertion loss of the phase shifter while maintaining high modulation efficiency because the optical phase shift is induced by carrier accumulation at the MOS interface. We experimentally demonstrated the proposed optical phase shifter with an ultrathin InP membrane and achieved the modulation efficiency of 0.

High-speed Ge/Si electro-absorption optical modulator in C-band operation wavelengths.

We studied a high-speed electro-absorption optical modulator (EAM) of a Ge layer evanescently coupled with a Si waveguide (Si WG) of a lateral pn junction for high-bandwidth optical interconnect. By decreasing the widths of selectively grown Ge layers below 1 µm, we demonstrated a high-speed modulation of 56 Gbps non-return-to-zero (NRZ) and 56 Gbaud pulse amplitude modulation 4 (PAM4) EAM operation in the C-band wavelengths, in contrast to the L-band wavelengths operations in previous studies on EAMs of pure Ge on Si. From the photoluminescence and Raman analyses, we confirmed an increase in the direct bandgap energy for such a submicron Ge/Si stack structure.

Differential receivers with highly -uniform MSM Germanium photodetectors capped by SiGe layer.

Waveguide integrated MSM (metal-semiconductor-metal) Germanium (Ge) photodetectors (PDs) with a SiGe capping layer were exploited for silicon photonics integration. Under optimized epitaxial growth conditions, the capping layer passivated the Ge surface, resulting in sufficiently low dark current of the PDs. In addition, the PDs exhibited a narrower distribution of the dark current than PDs with a Si capping layer, probably due to the lower surface leakage current.

First demonstration of high density optical interconnects integrated with lasers, optical modulators, and photodetectors on single silicon substrate.

Engineers are currently facing some technical issues in support of the exponential performance growths in information industries. One of the most serious issues is a bottleneck of inter-chip interconnects. We propose a new "Photonics-Electronics Convergence System" concept.

An intramedullary free vascularized fibular graft combined with pasteurized autologous bone graft in leg reconstruction for patients with osteosarcoma.

The use of pasteurized autologous bone graft has been an innovation in limb-salvage surgery; however, its principal disadvantage is fracture, infection, pseudoarthrosis, and bone resorption. We present two cases in which an intramedullary free vascularized fibular graft combined with pasteurized autologous bone graft was performed for immediate femur or tibia reconstruction following osteosarcoma resection. The rationale of this method is to combine the mechanical strength of a pasteurized bone with the biological activity of a vascularized bone.

Atypical Mycobacterium infections of the upper extremity.

Background: We encountered five patients with atypical Mycobacterium infections in the upper extremity, and examined their outcomes.

Patients And Methods: Two patients were male and three were female. The average patient age was 67 (range, 63-75) years.

Use of vascularized pedicle iliac bone graft combined with transtrochanteric rotational osteotomy in the treatment of avascular necrosis of the femoral head.

Introduction: A vascularized pedicle iliac bone graft combined with transtrochanteric anterior rotational osteotomy was performed in patients with extensive necrosis in whom the necrotic area occupied more than two-thirds of the weight-bearing zone of the femoral head. The purpose of this procedure is to supply vascularity and mechanical strength to the avascular femoral head.

Materials And Methods: Seventeen hips in 14 patients (8 male, 6 female) whose average age at surgery was 37.

Mechanism of hydrogen peroxide-induced apoptosis of the human osteosarcoma cell line HS-Os-1.

In our previous study, we examined radiation-induced ROS formation, oxidative DNA damage, early apoptotic changes, and mitochondrial membrane dysfunction in the human osteosarcoma cell line HS-Os-1, which was established from an osteoblastic tumor that arose in the left humerus of an 11-year-old girl and was already morphologically characterized in vitro and in vivo. We found that ROS formation and oxidative DNA damage were scarcely seen after irradiation of up to 30 Gy in these cells; that mitochondrial membrane potential was preserved; and that apoptotic changes were not demonstrated despite the relatively high-dose irradiation of 30 Gy. Based on these results, the radioresistance of the human osteosarcoma cell line HS-Os-1, was considered to arise, at least in part, from the low level of ROS formation following irradiation, which in turn may have resulted from the strong scavenging ability of the cells for free radicals, including hydroxyl radicals.

Mechanism of apoptotic resistance of human osteosarcoma cell line, HS-Os-1, against irradiation.

In our previous study, we examined reactive oxygen species (ROS) formation in T lymphocytes following 5 Gy of irradiation. Using a CCD camera system, we monitored fluorescence in T lymphocytes loaded with the succinimidyl ester of Dichlorodihydrofluorescein diacetate (H2DCFDA), which is non-fluorescent until oxidized by ROS. We found that ROS formation occurred immediately after irradiation, continued for several hours, and resulted in oxidative DNA damage.