Abstract: An optical fiber type magneto-optical head is capable of realizing satisfactory reductions in size and weight of a movable portion of an optical head. An extinction-type form of the optical fiber type magneto-optical head comprises a first optical device for condensing a polarized light beam and leading the light beam into a polarization-maintaining optical fiber, a second optical device for focusing light emerging from the optical fiber into a beam spot on a magnetic recording medium, a detector for detecting via the optical fiber light reflected from the magnetic recording medium with a change in polarized state, and an azimuth rotator disposed between the second optical device and the optical fiber, wherein the azimuth rotator is designed so that the angle of optical rotation upon one pass therethrough is.theta.k/2.+-.n.multidot.45.degree.where.theta.k/2.+-. : the Kerr rotation angle of a magnetic recording film of the recording medium,N= 0, 1, 2, . . . .

Abstract: A multi-port fiberoptic rotary joint comprising a trapezoid prism provided between a rotative member and a fixed member of the rotary joint so as to be rotatable relative to the rotative member and coaxial with said rotative member, a speed change gear mechanism for transmitting the rotation of the rotative member to the trapezoid prism so as to rotate the trapezoid prism at an angular velocity half the angular velocity of the rotative member, rhomboid prisms provided on the entrance side of the trapezoid prism so as to optically guide the light coming from a region outside an aperture of the trapezoid prism to the trapezoid prism as the light parallel to the axis of the trapezoid prism within the aperture thereof, and the rhomboid prisms provided on the exit side of the trapezoid prism so as to optically guide the light emanating from the trapezoid prism to a region outside the aperture of the trapezoid prism, a plurality of pairs of convergent lenses respectively provided to the rotative member and the fixe

Abstract: A fiber for lateral beaming of a laser beam, wherein an affected portion in a cavity of an internal organ in a living body is irradiated by the laser beam in a through-endoscopic manner. The fiber for lateral beaming of the laser beam is constructed such that a transparent tubular member is coupled to the forward end portion of a fiber through two coating layers, and an anti-reflection coating layer is formed on a laser beam exiting surface of the transparent tubular member. Owing to the anti-reflection coating layer, this fiber for lateral beaming is free from the harmful leaking beam. Since the transparent tubular member is connected to the fiber through the two coating layes, the fiber can avoid being broken.