Abstract: A dispersion compensator and method of dispersion compensation in which an input light is converted to a selected second wavelength, the converted light beam having the second wavelength is dispersion compensated in an amount dependent upon the second wavelength, and the compensated light beam having the second wavelength is converted to the first wavelength.

Abstract: The present invention has an object to provide an optical amplifier capable of realizing a good response characteristic in a wide frequency band, even when a population inversion state is formed by a pumping light supplied to an optical amplification medium and an ASE light generated in the optical amplification medium. To this end, in the optical amplifier according to the present invention, a delayed phase matching fiber in which a first fiber whose response speed is relatively low is arranged on the input side and a second fiber whose response speed is relatively high is arranged on the output side, is used as the optical amplification medium doped with a rare-earth element.

Abstract: An optical amplifier of the invention comprises first and second optical amplification sections connected in a cascade manner between an input terminal and an output terminal. Optical isolators which block C-band ASE travelling in an opposite direction to L-band signal light, are inserted on the amplification medium of each of the optical amplification sections. A constant gain control section calculates the number of wavelengths based on the input power of signal light, and controls the pumping light power of each optical amplification section at a constant slope with respect to the number of wavelengths, so that the respective gains in the optical amplification sections corresponding to the number of wavelengths each become constant. As a result, it is possible to maintain flat gain wavelength characteristics even when receiving input of WDM light where the number of wavelengths varies rapidly over a wide range.

Abstract: An optical amplifier of the invention comprises first and second optical amplification sections connected in a cascade manner between an input terminal and an output terminal. Optical isolators which block C-band ASE travelling in an opposite direction to L-band signal light, are inserted on the amplification medium of each of the optical amplification sections. A constant gain control section calculates the number of wavelengths based on the input power of signal light, and controls the pumping light power of each optical amplification section at a constant slope with respect to the number of wavelengths, so that the respective gains in the optical amplification sections corresponding to the number of wavelengths each become constant. As a result, it is possible to maintain flat gain wavelength characteristics even when receiving input of WDM light where the number of wavelengths varies rapidly over a wide range.

Abstract: The present invention has an object to provide an optical amplifier capable of realizing a good response characteristic in a wide frequency band, even when a population inversion state is formed by a pumping light supplied to an optical amplification medium and an ASE light generated in the optical amplification medium. To this end, in the optical amplifier according to the present invention, a delayed phase matching fiber in which a first fiber whose response speed is relatively low is arranged on the input side and a second fiber whose response speed is relatively high is arranged on the output side, is used as the optical amplification medium doped with a rare-earth element.

Abstract: A contrivance, if a WDM signal state changes, is to improve an optical transmission quality by compensating gain flatness. A first excitation control unit sets a first optical pumping light source unit to emit excitation power needed to get the same amplifying operating level of a first amplifying medium as at the time of a maximum wavelength count when allocating wavelengths after a change in wavelength count at an equal interval in a wavelength range. A wavelength allocation bias estimation unit compares a present monitor value of optical power after outputting of a gain equalizer 13 with wavelength equi-allocation power associated with the recognized wavelength count, and thus estimates a wavelength allocation bias occurred as a concomitant of the change in the wavelength count. A primary gradient calculation unit obtains a primary gradient quantity defines as a gain deviation from the wavelength allocation bias.

Abstract: A wavelength division multiplexed optical amplifier, enabling elimination of the problems of oscillation and fluctuation in output due to ASE at the time of a rapid change in the number of input wavelengths, provided with a first-stage optical amplifying unit, second-stage optical amplifying unit, a common AGC circuit for common AGC of the first and second optical amplifying units, and a pumping light distribution means for applying pumping light to the first and second-stage optical amplifying units with a predetermined distribution ratio.

Abstract: For providing an anti-bacteria which is made from a natural material, therefore harmless if it is absorbed in the human body, can be produced in mass production with low cost, and shows a high anti-bacteria effect, the anti-bacteria agent is obtained by heating a shell in an atmosphere of inactive gas and burning the shell under the temperature which finally reaches 700° C.-2,500° C.

Abstract: A dispersion compensator and method of dispersion compensation in which an input light is converted to a selected second wavelength, the converted light beam having the second wavelength is dispersion compensated in an amount dependent upon the second wavelength, and the compensated light beam having the second wavelength is converted to the first wavelength.

Abstract: A signal light passes through an isolator, and is coupled by a coupler with a pump light from a pump light source. Then, the signal light passes through an ASE reflection filter, is amplified by an EDF, and is transmitted from an isolator. At this time, an ASE light having a predetermined wavelength among ASE lights that occur within the EDF and proceed to the ASE reflection filter is reflected and again input to the EDF. By setting the predetermined wavelength to a wavelength on the short wavelength side of an amplification band of the EDF, gain deviation occurring on the long wavelength side of the amplification band can be cancelled.

Abstract: Optical signals (multi-wavelength light) are guided to an EDF. The EDF is supplied with pump light generated by a first and a second pump light sources. Dummy light is generated by a dummy light source and supplied to the EDF. The wavelength of the dummy light is shorter than a wavelength range in which the optical signals are allocated.

Abstract: For providing an anti-bacteria which is made from a natural material, therefore harmless if it is absorbed in the human body, can be produced in mass production with low cost, and shows a high anti-bacteria effect, the anti-bacteria agent is obtained by heating a shell in an atmosphere of inactive gas and burning the shell under the temperature which finally reaches 700° C.-2,500° C.

Abstract: For providing an anti-bacteria which is made from a natural material, therefore harmless if it is absorbed in the human body, can be produced in mass production with low cost, and shows a high anti-bacteria effect, the anti-bacteria agent is obtained by heating a shell in an atmosphere of inactive gas and burning the shell under the temperature which finally reaches 700° C.-2,500° C.

Abstract: A signal light passes through an isolator, and is coupled by a coupler with a pump light from a pump light source. Then, the signal light passes through an ASE reflection filter, is amplified by an EDF, and is transmitted from an isolator. At this time, an ASE light having a predetermined wavelength among ASE lights that occur within the EDF and proceed to the ASE reflection filter is reflected and again input to the EDF. By setting the predetermined wavelength to a wavelength on the short wavelength side of an amplification band of the EDF, gain deviation occurring on the long wavelength side of the amplification band can be cancelled.

Abstract: Optical signals (multi-wavelength light) are guided to an EDF. The EDF is supplied with pump light generated by a first and a second pump light sources. Dummy light is generated by a dummy light source and supplied to the EDF. The wavelength of the dummy light is shorter than a wavelength range in which the optical signals are allocated.

Abstract: For providing an anti-bacteria agent which is made from a natural material, therefore harmless if it is absorbed in the human body, produced in mass production with low cost, and showing a high anti-bacterial effect, the anti-bacteria agent is obtained by heating a shell in an atmosphere of inactive gas and burning the shell under the temperature which finally reaches 700° C.-2,500° C.

Abstract: For providing an anti-bacteria which is made from a natural material, therefore harmless if it is absorbed in the human body, can be produced in mass production with low cost, and shows a high anti-bacteria effect, the anti-bacteria agent is obtained by heating a shell in an atmosphere of inactive gas and burning the shell under the temperature which finally reaches 700° C. - 2,500° C.

Abstract: A measles vaccine virus AIK-C strain comprises genomic RNA that produces by reverse transcription cDNA having a specific nucleotide sequence indicative of the viral genomic RNA in the seed virus for measles vaccine or measles virus vaccine. The complete sequence of 15,894 nucleotides has been determined.

Abstract: A measles vaccine virus AIK-C strain comprises genomic RNA that produces by reverse transcription cDNA having a specific nucleotide sequence indicative of the viral genomic RNA in the seed virus for measles vaccine or measles virus vaccine. The complete sequence of 15,894 nucleotides has been determined.

Abstract: A stabilized live attenuated vaccine with improved thermal stability, which comprises a live attenuated plain vaccine consisting of measles, mumps or rubella virus grown in a medium-199 for cell culture, or a combined live attenuated vaccine thereof, containing a stabilizing agent at a final concentration of lactose 2.5-5 W/V %, saccharose 2.5-5 W/V %, D-sorbitol 1.8-2 W/V %, sodium glutamate about 0.1 W/V % and gelatin hydrolyzate, M.W. approx. 35,000, 2-3 W/V %.