Abstract: Non-linear optical characteristics of a carbon nanotube are applied to an optical communication field. An optical transmission medium (12) obtained by incorporating a carbon nanotube having optically non-linear characteristics into a non-linear light transmitting medium is assembled between typical optical transmission medium (14a, 14b) and is used by being combined with an optical circulator (16), whereby the resultant product is used as an optical fuse (breaker) that transmits a normal signal light A but blocks the transmission of an abnormal-intensity light inadvertently produced.

Abstract: An optical element according to the present invention has a thin film, in which single-wall carbon nanotubes are laminated, and utilizes a saturable absorption function of the single-wall carbon nanotubes. Further, in a method for producing the optical element according to the present invention, the thin film is formed by spraying, to a body to be coated, a dispersion liquid prepared by dispersing the single-wall carbon nanotubes in a dispersion medium. Accordingly, a nonlinear optical element, which can operate in an optical communication wavelength region and which is extremely inexpensive and efficient, and a method for producing the optical element can be provided.

Abstract: An increase in the span of the transmission distance is aimed at by reducing unwanted ASE generated during optical communication. A carbon nanotube is employed as a saturable absorber 15 and this saturable absorber constitutes a noise reduction apparatus that has the function of cutting off or reducing transmission of unwanted ASE or the like which is of weak signal light intensity and of allowing transmission of signal light of strong light intensity. This noise reduction apparatus is arranged for example in the transmission path of signal light of a bidirectional excitation type EDFA, more precisely the apparatus is inserted in the latter stage of the EDF 40. In this way, carbon nanotubes having a saturable absorption function can be utilized in the field of optical communication.

Abstract: An optical element according to the present invention has a thin film, in which single-wall carbon nanotubes are laminated, and utilizes a saturable absorption function of the single-wall carbon nanotubes. Further, in a method for producing the optical element according to the present invention, the thin film is formed by spraying, to a body to be coated, a dispersion liquid prepared by dispersing the single-wall carbon nanotubes in a dispersion medium. Accordingly, a nonlinear optical element, which can operate in an optical communication wavelength region and which is extremely inexpensive and efficient, and a method for producing the optical element can be provided.

Abstract: A substance-occluding material, an electrochemical device employing same and a method of producing same are provided. The substance-occluding material wherein a substance, for example, a fullerene molecule, different from a substance to be occluded, such as hydrogen gas, is contained in the inside of a tubular material, such as carbon nanotube.