Chirping compensation using a two-section semiconductor laseramplifier

Compensation of light source chirping and optical fiber dispersion using semiconductor laser amplifiers (SLAs) is investigated using a modeling equation that describes the opposite phase characteristics of light sources to SLAs with self phase modulation. A two-section SLA was fabricated in order to achieve an amplifier with both high gain and phase compensation properties. Preliminary experimental results are presented, confirming the theoretically derived phase compensation effect     

Image template matching based on edge‐spin correlation

This paper proposes a new method for image template matching that is based on the correlation between edge‐spins. The edge‐spin is defined by the direction of the change of edge directions between neighboring pixels. When an edge direction rotates to the left from an objective pixel to its right neighboring pixel, the edge‐spin has the value 1. When an edge direction rotates to the right, the edge‐spin has the value 0. The edge‐spin is a binary data that represents the rotation of the edge direction. The edge‐spin is supposed to be robust to the change of brightness because the edge direction is not influenced by the linear change of brightness. The experimental results show that the proposed method has the superior reliability for the matching about most inferior experimental conditions in comparison with the conventional image template matching methods. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(2): 45–51, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20184     

A GaInAsP/InP tapered-waveguide semiconductor laser amplifierintegrated with a 1.5 μm distributed feedback laser

A GaInAsP/InP index-guided type tapered-waveguide traveling-wave semiconductor laser amplifier (TTW-SLA) with exponential taper structure was realized for the first time and its integration with a 1.5 μm wavelength phase adjusted DFB laser was demonstrated. A reasonable amount of the single-pass gain, which was limited by the residual reflectivity at the output end of the amplifier region, was obtained with no serious problem with the lasing spectrum. A narrow beam divergence of FWHM=5.5° and stable longitudinal mode operation were obtained with the output waveguide width of 20 μm by adopting both a window structure and 7° angled facets. This value agrees well with the theoretically calculated one and proves that single transverse-mode propagation can be attained by an exponentially tapered TTW-SLA with a very wide output end     

Impact of fibre span configuration on Raman gain shape in dispersion-flattened transmission systems

The precise inherent Raman gain shape of several types of dispersion-flattened fibre span was evaluated under different operating conditions in backward pumping. It was found that the overall gain shape greatly depends on the fibre span configuration rather than the operating condition in any fibre span configurations.     

Production of macrocyclic ellagitannin oligomers by Oenothera laciniata callus cultures

Melanocyte-stimulating hormone (MSH) has been reported to enhance the experimental metastatic behaviour of melanoma cells in the mouse model. alpha-MSH production and MSH receptor (melanocortin 1 receptor gene) expression have been detected in cultured normal human melanocytes and metastasized melanomas. The exact role of MSH in the metastatic behaviour of human melanoma cells is, however, not yet known. To clarify a possible role of proopiomelanocortin (POMC)-derived peptides, including alpha-MSH, in melanoma development and progression, we analysed immunohistochemically the localization of alpha-MSH adrenocorticotrophic hormone (ACTH) and beta-endorphin in various kinds of benign pigmented naevocytic lesions and malignant melanomas. Three of 21 samples of common and dysplastic naevi showed detectable alpha-MSH staining in naevus cells, and five and six of 15 samples were weakly positive for ACTH and beta-endorphin staining, respectively. In melanoma samples, 24 of 45, 23 of 39 and 30 of 42 samples showed positive staining with alpha-MSH, ACTH and beta-endorphin antibodies, respectively. Furthermore, staining for all three antibodies was noted to be more intense and diffuse in samples of nodular melanoma, vertically growing acral lentiginous melanoma and superficial spreading melanoma as well as metastatic lesions compared with those of naevi. Although it is yet to be determined whether or not this strong staining for POMC-derived peptides in advanced melanoma cells indicates a role of autocrine or paracrine regulation, our results suggest a possible involvement of POMC gene products in melanoma progression.     

Saturation measurements on electron spin resonance signals in amorphous silicon films

The dependence of the electron spin resonance signal intensity on the microwave magnetic field was investigated for amorphous silicon prepared by r.f. sputtering. The spin-lattice and the spin relaxation times T₁ and T₂ were determined by a new saturation method. As a result it is suggested that the electron spin resonance linewidth is determined by g-factor anisotropy, that T₂ is 10–100 times longer than the T¹₂ determined from the linewidth, that T₁ for samples annealed at below about 250°C is proportional to T^-1.9 and that most of the spins for samples annealed at above 400°C are probably due to dangling bonds in amorphous regions surrounding crystallites newly produced in the process of crystallization.     

A study on product modelling for integration of CAD/CAM

Modelling capability for products to be designed and manufactured plays an important role in order to effectively construct and utilize CAD/CAM systems. Product models should represent all the information about products, which is utilized in manufacturing processes. Therefore it is required that they describe functional structures of machine products, and include not only geometric information but also various non-geometric data, such as physical, technological and management data. Presently there do not seem to exist definite methods or theories for constructing product models. In this paper, we first investigate the whole manufacturing process, and propose a system structure for integration of CAD/CAM, in which product modelling plays a fundamental role. Then requirements for product modelling are studied thoroughly, and a new representation framework for product models is proposed. It consists of an object concept called frame, relations among frames and attributes, and it can incorporate the existing various modelling capabilities, such as solid modelling. We use this representation framework in combination with our solid modelling package GEOMAP-III, and show the effectiveness of this approach by performing illustrative design experiments.