Abstract: With the present invention, glycoalbumin and hemoglobin A1c are measured in a blood sample, and the incidence of or the existence or non-existence of a development risk of Alzheimer's disease can then be determined based on the calculated glycoalbumin/hemoglobin A1c ratio. Compounds for treating or preventing Alzheimer's disease can also be selected using this glycoalbumin/hemoglobin A1c ratio.

Abstract: A multiplexing transmission system for adding a management overhead to a client signal, and transparently accommodating or multiplexing the client signal to transmit it is provided. The multiplexing transmission system: accommodates a plurality of client signals of different bit rates including a client signal of a bit rate that is not an integral multiple or an integral submultiple of a bit rate of other client signal, and performs rate adjustment for a part or the whole of the plurality of client signals such that the bit rate of each client signal becomes an integral multiple or integral submultiple of the bit rate of other client signal.

Abstract: A multiplexing transmission system for adding a management overhead to a client signal, and transparently accommodating or multiplexing the client signal to transmit it is provided. The multiplexing transmission system: accommodates a plurality of client signals of different bit rates including a client signal of a bit rate that is not an integral multiple or an integral submultiple of a bit rate of other client signal, and performs rate adjustment for a part or the whole of the plurality of client signals such that the bit rate of each client signal becomes an integral multiple or integral submultiple of the bit rate of other client signal.

Abstract: A wavelength division multiplexing ring network is constructed using a simple architecture and a fewer number of hardwares between the nodes compared with the conventional ring network. Each node is structured so that any number of multiple waves can be processed, and a fault in the network or within a node is resolved by providing a path-based protection so that switching can be performed without disrupting other nodes or even within one node.

Abstract: By using a combination of a plurality of completely unequally spaced channel allocations, the influence of four wave mixing is mitigated even while it is incompletely unequally spaced channel allocation, and it is possible both to decrease the occupied bandwidth and increase the number of channels. A plurality of completely unequally spacing channel allocations are combined, and the number of channels changes depending on the amount of scattering of an optical fiber and the frequency that there exists zero dispersion wavelengths on a transmission path. The completely unequally spaced channel allocations of N1-channels in a first wavelength region including the zero dispersion wavelength &lgr;0 or the mode zero dispersion wavelength &lgr;A are partitioned, and then in sequence the completely unequally spaced channel allocation of N2-, N3-, . . . , channels is partitioned, and the wavelength interval of N channels is set by combining all or a part thereof (where N1≧N224 . . . >Nj≧Nk−1≧Nk).

Abstract: An optical amplifier evaluating device has a wavelength multiplex signal light generating section, and an O/E converter, and a frequency discriminating and power detecting device, and a computing section. The wavelength multiplex signal light generating section generates an wavelength multiplex signal light which includes signal lights having different wavelengths and having intensity envelopes modulated by different modulation frequencies which are enough higher than an atom life time in a high energy level or a carrier life time in an amplification medium of an optical amplifier to be evaluated, and supplies the wavelength multiplex signal light to the optical amplifier. The O/E converter converts an output light of the optical amplifier to an electric signal.

Abstract: An optical cross-connect system is provided with M fixed wavelength light sources and external modulators corresponding to respective optical paths, serving as light sources for wavelength conversion devices corresponded to M.times.N optical paths. By means of electrical signals for the converted optical signals carried on the M.times.N optical paths, CW lights input to the external modulators from the respective light sources are modulated, wavelength converted and then output. Accompanying this wavelength conversion, wavelength multiplexed light sources which can select lights from a plurality of fixed wavelength light sources and output to predetermined output ports, are used for the light sources of the plurality of wavelength conversion devices of the cross-connect system. In this way, the light sources of a plurality of wavelength conversion sections are commonalized using a fixed wavelength light source.

Abstract: A multiwavelength simultaneous monitoring circuit capable of precise discrimination of wavelengths of a WDM (Wavelength Division Multiplexed) signal including multiplexed wavelength waves, and suitable for optical integrated circuits having large resistance to vibration.

Abstract: The optical circulator according to the present invention comprises three birefringent crystal plates 22, 23, and 24; reciprocal and non-reciprocal rotators 25 of the first group inserted between birefringent crystal plates 22 and 23; reciprocal and non-reciprocal rotators 26 of the second group inserted between birefringent crystal plates 23 and 24; and more than two beam incoming and outgoing ports 27, 28, and 29. The rotating directions of the reciprocal and non-reciprocal rotators 25 of the first group are so set that the directions in which ordinary beam and extraordinary beam are separated on the birefringent crystal plates differ among birefringent crystal plate 23 and birefringent crystal plates 22 and 24, and the electric field vibration directions of the beams agree at birefringent crystal plate 23.

Abstract: An optical wavelength demultiplexer including an optical conversion device which converts a difference in wavelengths of a plurality of input signals into a difference in spatial power distribution of the input light signals, and a pattern recognition element for recognizing patterns of the spatial power distribution and taking out output signals. At the output portion of the optical conversion device, spatial power distributions are formed which are different for different wavelengths. After converting the spatial power distributions by the pattern recognition element into electrical signals, pattern recognition of the signals is performed to regenerate the original input signals with their respective wavelengths. The optical conversion device uses a diffractive grating or a combination of an optical multimode circuit, an optical multimode fiber, and a plurality of optical wavelengths.