Abstract: The present invention is to provide a method for identifying an optical line easily and accurately regardless of the optical line length. A plurality of reflecting parts is placed on the optical line, and a combination of relative positions of the reflecting parts is changed for every optical line to form an identification code, and the relative positions of the reflecting parts are detected based on reflected lights when a detecting light is inputted to the optical line, so that the optical line is identified based on a result. Concretely, when the detecting light is inputted to one end of the optical line, the light is reflected at the plurality of the reflecting parts which form the identification code and comes back the input end. A combination of the relative positions etc. of the reflecting parts is changed for every optical line.

Abstract: The present invention is to provide a method for identifying an optical line easily and accurately regardless of the optical line length. A plurality of reflecting parts is placed on the optical line, and a combination of relative positions of the reflecting parts is changed for every optical line to form an identification code, and the relative positions of the reflecting parts are detected based on reflected lights when a detecting light is inputted to the optical line, so that the optical line is identified based on a result. Concretely, when the detecting light is inputted to one end of the optical line, the light is reflected at the plurality of the reflecting parts which form the identification code and comes back the input end. A combination of the relative positions etc. of the reflecting parts is changed for every optical line.

Abstract: An optical isolator not dependent on the plane of polarization of an incident beam and does not allow the plane of polarization to change on the outgoing side. The optical isolator comprises a first parallel flat double refractive crystal substance; a first Faraday rotor for rotating the plane of polarization of a beam; a second parallel flat double refractive crystal substance; a second Faraday rotor for rotating the plane of polarization in a direction opposite to that in which said first Faraday rotor rotates the plane of polarization; a third parallel flat double refractive substance; a fourth parallel flat double refractive substance; and permanent magnets for magnetizing the Faraday rotor and second Faraday rotors. Since a pair of Faraday rotors for rotating the plane of polarization in opposite directions, the plane of polarization on the incident side does not change on the outgoing side.

Abstract: A method for manufacturing a fiber-optic collimator which comprises the steps of projecting a beam of light, emerging outwardly from an optical fiber, through a lens onto a planar reflecting medium so as to reflect therefrom, causing the reflected beam of light to enter the fiber through the lens, and adjusting a relationship in position between the lens and the fiber such that the intensity of the reflected beam of light entering the fiber attains a maximum value. The lens and the fiber are then fixed in position when an indication is provided that the intensity of the reflected beam of light has attained the maximum value.

Abstract: A method of and apparatus for examining the structure of an optical fiber such as eccentricity, clad and core diameters, and nonroundness of clad. The structure of the optical fiber can be accurately determined by irradiating the side wall of the optical fiber with a light such as a white light, a monochromatic light or the like in the direction perpendicular to the axis of the optical fiber, detecting an image of the light transmitted through the optical fiber and/or diffraction fringes formed by lights diffracted by the outer edge of the optical fiber to obtain a luminance distribution of the light traversing the optical fiber, and calculating the luminance distribution to thereby obtain accurate structural parameters of the optical fiber.