Possible future applications of photonic bandgap fiber in non-repeatered transmission systems

We investigate the potential use of photonic bandgap fibers in non repeatered transmission systems. Our simulations show that significant improvements in system reach should be possible as a result of the reduced nonlinearity providing that the fiber losses can be reduced to the 0.2 to 0.3dB/km regime

Application of Near-Infrared Diffuse Reflectance Spectroscopic Analysis for Estimating the Ratio of True Seed Weight to Fruit Weight in Sugar Beet Seed

The feasibility of near-infrared diffuse reflectance spectroscopic analysis (NIR analysis) for estimating the ratio of true seed weight to fruit weight (T/F) as well as water content was examined in sugar beet (Beta vulgaris L.) seeds of 61 F1 hybrid lines and 4 standard cultivars. For the calibration, partial least squares (PLS) regression was carried out with second derivative spectra and the measured data using attached software (NSAS). For estimating T/F, calibration using 7 factors was the most valid with a correlation coefficient of calibration (R) of 0.943, standard error of calibration (SEC) of 1.26% and standard error of prediction (SEP) of 1.40%. By this calibration, sugar beet varieties could be classified into 4∼5 levels according to the estimated T/F. For the estimation of the water content of sugar beet seed, calibration using 14 factors was optimal. The calibration was highly accurate since the R, SEC and SEP was 0.999, 0.23% and 0.27% respectively. Consequently, the true seed weight of sugar beet could be nondestructively and rapidly estimated by NIR analysis and weighing the air-dried seed. This technique should be useful in breeding selection for higher true seed weights, which would thereby improve the early growth of sugar beet varieties

TDM-to-WDM conversion from 130 Gbit/s to 3X43 Gbit/s using XPM in a NOLM switch

We report the first demonstration of OTDM-to-WDM conversion from 130 Gbit/s simultaneously to 3 × 43 Gbit/s WDM channels in a nonlinear optical loop mirror (NOLM). The scheme is exploiting the ultra-fast Kerr based XPM in a NOLM and gives full flexibility for selecting the output WDM channel wavelengths. For the success of the experiment we rely crucially on a new specially designed highly nonlinear fiber (HNLF) exhibiting low dispersion and low dispersion slope such that low walk-off operation across the C-band is possible. Error free performance is achieved with penalties ranging from 0.5 dB to 3.5 dB for all three WDM channels

Investigation on multi-core fibers with large Aeff and low micro bending loss

To realize large effective area (Aeff) multi-core fibers (MCFs), the design to suppress the cross-talk and the influence of the cladding diameter on the micro bending loss were investigated. As a result, the MCFs with large Aeff over 100 μm2 and low micro bending loss were successfully fabricated. The results indicate the importance of fiber design to realize large Aeff MCFs including fiber diameters, which largely affect the micro bending loss property. Additionally, MCF with large Aeff, low attenuation loss and suppressed cross-talk was successfully realized by optimizing the fiber design. The cross-talk properties could be estimated by the simulation based on the coupling power theory taking the influences of the longitudinal fluctuation of core diameter into account

Accumulation of Soluble Sugar in True Seeds by Priming of Sugar Beet Seeds and the Effects of Priming on Growth and Yield of Drilled Plants

For improving the yield of drilled sugar beet (Beta vulgaris L. ssp. vulgaris), it is important to promote germination and early growth. In this study, the priming of sugar beet seeds was examined in six cultivars to improve their germinability in cool conditions. The optimum water content of sugar beet seeds (which botanically are fruits) during priming was 24 to 25% when they were kept at 20°C for 5 d. In further experiments, after the water content of seeds was adjusted to 24% by adding distilled water, the primed seeds were air-dried to below their original water content. The primed true seeds contained 0.5 to 4% more soluble sugar, by dry weight, than the control true seeds. The levels of amylase activity of the primed true seeds were 1.9 to 11.5 times higher than those of the control true seeds, though there was little change in α-glucosidase activity. Priming shortened the average germination period at 8°C by 1.6 to 4.0 d and seedlings from the primed seeds emerged significantly faster than did seedlings from the control seeds in the field. The advanced emergence in the primed seeds brought about a significant increase in early growth compared with control seeds, and the root yield from the primed seeds tended to exceed that from the control seeds by 3% on average at harvest time. Priming did not affect the sugar, potassium, sodium or amino nitrogen content in the root

Design scaling rules for 2R-optical self-phase modulation-based regenerators

We present simple scaling rules to optimize the design of 2R optical regenerators relying on Self-Phase Modulation in the normal dispersion regime and associated offset spectral filtering. A global design map is derived which relates both the physical parameters of the regenerator and the properties of the incoming signal to the regeneration performance. The operational conditions for optimum noise rejection are identified using this map and a detailed analysis of the system behavior under these conditions presented. Finally, we demonstrate application of the general design map to the design of a regenerator for a specific 160 Gb/s system

Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using parabolic pulses formed in a fiber Bragg grating

We propose a new method for generating flat self-phase modulation (SPM)-broadened spectra based on seeding a highly nonlinear fiber (HNLF) with chirp-free parabolic pulses generated using linear pulse shaping in a superstructured fiber Bragg grating (SSFBG). We show that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses. We demonstrate both numerically and experimentally the generation of SPM broadened pulses centred at 1542nm with 92% of the pulse energy remaining within the 29nm 3dB spectral bandwidth. Applications in spectral slicing and pulse compression are demonstrated