| 摘要 |
PURPOSE:To remove heating destruction due to coupling loss at an incident end and to transmit large power by forming the incident end of a hollow optical waveguide as a taper-like aperture having a specific expanding angle. CONSTITUTION:The expanding angle 2theta of the single end part of the hollow optical waveguide is formed as the taper-like aperture having the expanding angle 2theta=2lambda/Ka (0.4<=K<=0.65) (provided that 2a is the inner diameter of the hollow optical waveguide and lambda is the wavelength of a laser beam). In the case of producing the hollow optical waveguide, a conical body having a taper face with the expanding angle 2theta is heated and pressed against to the end part of a parent pipe 4 to form the optical waveguide. After forming a Ge dielectric thin film 7 and an external metallic layer 6 consisting of Ni or the like successively on the outside of the pipe 4, the pipe 4 is removed by etching. Since the incident end is shaped like a taper, the concentration of coupling loss can be suppressed and large power can be stably transmitted. |
