Abstract: A laser diode module in which an optical system that magnifies NFP of the laser diode by twice or more and ten times or less is disposed along an optical axis z of a laser light from a laser diode, an elliptic core GI type optical fiber of a predetermined length and an elliptic core cross section with the major radius direction and the minor radius direction being aligned with the direction x and the direction y of the NFP respectively is disposed at an image formation position of the optical system, and a single mode optical fiber connected is connected to a light emitting end of the elliptic core GI type optical fiber, the diode module providing an advantage that the design and manufacture for the optical system are simple, production cost is reduced and a laser light even at a high aspect ratio can be introduced into a single mode optical fiber at a high coupling efficiency of 60% or more.

Abstract: A lensed optical fiber and a semiconductor laser module, characterized in that first and second optical fibers, each including a core and a cladding, are connected to one end of a single-mode fiber, including a core and a cladding, in the order named. The core of the first optical fiber has a first square-low index distribution and a length substantially equal to 1/4 of the meandering period of light propagating through the core or an odd multiple thereof. The core of the second optical fiber has a second square-low index distribution and a meandering period different from that of the first optical fiber.

Abstract: An optical module and a temperature control method therefor, wherein the optical module includes a light-emitting device, an optical waveguide, a cooling device for cooling the light-emitting device, and a package for containing the light-emitting device, one end portion of the optical waveguide and the cooling device, and wherein the light-emitting device and the optical waveguide are optically coupled to each other. The optical waveguide has a grating section formed at the one end portion contained in the package for selectively reflecting only light with a fixed wavelength, and the cooling device cools the grating section in addition to the light-emitting device.

Abstract: A lensed-fiber including a single-mode fiber having a core and a cladding, a coreless fiber having a coreless isotropic refractive index and a convex surface at a first end thereof, and a square-law index fiber having a square-law index profile. The square-law index fiber is positioned between the single-mode fiber and the coreless fiber so as to connect an end of the single-mode fiber to a second end of the coreless fiber. The lensed-fiber may be arranged in a optical module facing an optical semiconductor element which emits a light beam to be propagated through the single-mode fiber.

Abstract: An actuator used shape memory alloy and a display conversion device of signs characterized in that, in the actuator equipped with a shape memory alloy allowing a movable body to work in one direction by the restoration force to the memorized shape at the time of temperature rising, a control base standing opposite to at least part of said movable body is provided, concave portions are provided to one of said movable body and control base and, at the same time, a control element is provided to the other thereof to guide said control element to said concave portion and to press said concave portion and control element against one another by a fixed resilience.

Abstract: A method of inexpensively fabricating a superconducting cavity having thin, clean, and smooth superconductive films of excellent resonance characteristics, and the steps of forming a first thin film layer made of hydrogen transmission-preventive metal on the outer periphery of the core made of a metal having a higher ionization tendency than hydrogen in the electrochemical series, then forming a second thin film layer of superconducting material on the outer periphery of the first thin film layer, forming a third thin film layer made of a metal having a high thermal conductivity and a high bondabilty on the outside of the second thin film layer, forming a reinforced coating layer of stabilizing metal through composite fiber plated with copper on tungsten fiber on the third thin film layer, forming a cooling pipe on the outside, and then removing the core and the first thin film layer by dissolving with the surface of the superconductor being a replica of the core surface.