Modal dispersion characteristics of LP modes in a step-index multimode fiber.

A modal interferometer method (MIM) is applied to measure the differential mode delay (DMD) between the modes traversing a step-index multimode fiber (SI-MMF). Only linearly polarized radial modes, i.e.

DEVELOPMENT OF A ROBOT FOR THE MEASUREMENT OF RADIOACTIVE CONTAMINATION AND FERTILITY OF THE SOIL IN FARMLAND.

A tractor-based robot with the capability of real-time assessing and visualizing the radioactive material density and fertility distribution of farmlands has been developed to accelerate the recovery process of the farmlands suffered by the accident of the Fukushima Daiichi Nuclear Power Plant (FDNPP). In a field test at a decontaminated farmland near FDNPP, within-field heterogeneities of soil contamination and fertility are clarified almost in real-time. Results obtained by this robot are consistent with the map by the conventional soil sampling or the history of decontamination activities.

Repetitive afterglow in zirconia by pulsed near-infrared irradiation toward biological temperature sensing.

Photoluminescence provides information about the surrounding environment. In this study, aiming to develop a non-invasive deep body-temperature sensing method, we investigated photoluminescence properties of afterglow zirconia (ZrO) by pulsed near-infrared (NIR) light irradiation based on the biological temperature. Pulsed light irradiation produced optically stimulated luminescence, followed by afterglow, with the property of repeating 100 times or more.

Differential mode delay diagnostics for LP modes traversing a few-mode fiber.

We provide differential mode delay (DMD) diagnostics for linearly polarized (LP) modes traversing a few-mode fiber (FMF). We employ a modal interferometer method with a butt coupling mechanism to measure the DMD between any two modes guided in FMFs with step-index (SI) and depressed-cladding profiles. The measurement principle is based on investigating a transmitted spectrum through temporal decomposition by means of a Fourier transform.

Measurement of fiber parameters of pure silica core fibers based on the OTDR technique.

We propose a simple technique based on optical time domain reflectometry (OTDR) for measuring the cutoff wavelength and core radius distributions in a pure silica core fiber for the first time. The proposed technique can simultaneously measure several important fiber parameters such as the mode field diameter, relative-index difference, effective area, and chromatic dispersion, including the cutoff wavelength and core radius. We experimentally demonstrate that our proposed technique can successfully evaluate these fiber parameter distributions and can be applied for the measurements of few-mode and multi-core fibers with pure silica cores using multi-channel OTDR and mode couplers.

Diagnosis of modal and chromatic dispersions for the LP and LP modes through temporal decomposition by means of Fourier transform.

We provide a novel approach for estimating the modal and chromatic dispersions of the and modes traversing a two-mode fiber (TMF). A modal interferometer is used to measure the differential group delay (DGD) and chromatic dispersion for the two modes in the 1260-1360 nm telecommunication band. The measurement principle is based on an investigation of a transmitted spectrum through temporal decomposition by means of a Fourier transform.

Temperature dependence of afterglow in zirconia and its optically-stimulated luminescence by bone-through irradiation for biological temperature probe.

Development of minimally invasive and site-selective biological temperature sensing is quite important in medical field. This study presents a novel temperature sensing technique based on afterglow and optically-stimulated luminescence (OSL). The dependence of afterglow photoluminescent intensity on the environmental temperature of zirconia (ZrO) phosphor is examined to validate its use as a sensing probe.

Unique loss characteristics in TE modes of conventional photonic bandgap fibers.

We report modeling that demonstrates the reduction of transmission loss and broadening of the bandwidth of a conventional hollow-core photonic bandgap fiber (PBF). Numerical investigation reveals that transmission loss of the high-order TE mode is lower than that of the fundamental HE mode in fibers with thick cladding walls. By comparing dispersion curves of PBFs with different core-wall thicknesses, we show that the TE mode has weaker coupling strength to a surface mode than the HE mode.

Study of fabrication reproducibility of two-mode optical fibers for mode division multiplexing with MIMO processing.

We propose a two-mode optical fiber (TMF) with a low sensitivity of differential modal group delay (DMD) to change of the core radius and the refractive index of the core in the index profile which are major factors for DMD deviation. This was done to achieve high reproducibility of fiber fabrication. The proposed TMF has a graded index (GI) core and a depressed inner cladding, and we optimize structural parameters.

CD56(dim)CD16(high) and CD56(bright)CD16(-) cell percentages associated with maximum knee extensor strength and incidence of death in elderly.

Physical fitness is an indicator of systemic well-being in humans. Little is known about the role of physical fitness for maintaining systemic health in the elderly. Here, we study elderly subjects to determine the relationships between physical fitness and CD56 and CD16 surface NK cell markers on peripheral blood lymphocytes, as well as to analyze the relationship between the surface markers and incidence of death.

Longitudinal fiber parameter measurements of multi-core fiber using OTDR.

A novel technique is proposed for measuring the longitudinal fiber parameters of multi-core fiber (MCF). The mode field diameter (MFD)of a fiber link composed of MCF is successfully estimated with a modified optical time domain reflectometer (OTDR). The measurement accuracy of the MFD distribution is revealed by simulation as a function of the mode coupling coefficient.

Two mode optical fibers with low and flattened differential modal delay suitable for WDM-MIMO combined system.

We propose two mode optical fibers (TMFs) with minimally low differential modal delay (DMD) slope which are suitable for wavelength division multiplexing and multiple input multiple output (MIMO) combined transmission system. We designed and fabricated three different kinds of TMF, nearly zero-DMD (zTMF), positive-DMD (pTMF) and negative-DMD (nTMF) with a graded index core and a depressed inner cladding. We confirmed that the fabricated zTMF has DMD of below 15 ps/km in the C band and the fabricated pTMF and nTMF have the same degree of effective areas.

Optimized graded index two-mode optical fiber with low DMD, large A(eff) and low bending loss.

An optimized two-mode optical fiber (TMF) with the graded index (GI) profile is designed and fabricated. We clarify an appropriate region of GI-TMF satisfying DMD = 0 ps/km, the large effective area A(eff), and the low bending loss for LP(11) at 1550 nm. According to our fiber design, GI-TMF is successfully fabricated to have the large effective area A(eff) of 150 μm(2) for LP(01) mode, and low DMD below 36 ps/km including zero in the C-band.

Physical performance and 10-year mortality in a 70-year-old community-dwelling population.

Background And Aims: Poor physical performance is known to be inversely related to mortality. The purpose of the present study was to determine whether an association between physical performance and 10-year mortality could be extended to a Japanese 70-year-old community-dwelling population, and to compare findings with those found in an octogenarian population.

Methods: Seventy-year-old subjects residing in Niigata city, Japan, participated.

Influence of dental occlusion on physical fitness decline in a healthy Japanese elderly population.

The aim of this study was to clarify the relationship between dental occlusion and physical fitness by a longitudinal survey. A sample of 348 subjects (171 men and 177 women) aged 71 was investigated by Eichner index (EI) as an occlusal condition (Class A: no loss; Class B: partial loss; Class C: complete loss) and five types of physical fitness tests and were re-examined 8 years later. The upper 50% were sampled to analyze the correlation between each physical fitness decline and the EI at the baseline by logistic regression models.