Abstract: The optical fiber 1 for an optical fiber laser is provided with a rare earth element doped core 2 doped with a rare earth element, and a cladding 3 formed at an outer periphery of the rare earth element doped core 2. In the optical fiber 1 for an optical fiber laser, the rare earth element doped core 2 is divided into a plurality of core regions 2a, 2b, . . . , 2n?1, 2n along a longitudinal direction of the optical fiber 1 and dopant concentrations of the rare earth element in respective core regions 2a, 2b, . . . , 2n?1, 2n are different from each other, in order to flatten a temperature distribution of the optical fiber 1 along the longitudinal direction.

Abstract: The optical fiber 1 for an optical fiber laser is provided with a rare earth element doped core 2 doped with a rare earth element, a cladding 3 formed at an outer periphery of the rare earth element doped core 2, a core vicinity part 3? of the cladding 3 provided in vicinity of the rare earth element doped core 2 being doped with a refractive index increasing agent which reduces a relative refractive index difference between the core vicinity part 3? and the rare earth element doped core 2 to be 0.1% or less.

Abstract: A plurality of light emitting elements 11 are arranged in parallel with a constant pitch to provide a semiconductor laser bar 10. An optical waveguide 20 has a core part 21 for guiding a light emitted from each of the light emitting elements 11 and a cladding part 22 formed around the core part 21. An optical fiber 30 has a core 31 and a cladding 32 formed around the core 31 for confining the light to the core 31. The optical waveguide is bonded to a side surface of the optical fiber 30, and the light emitted from the semiconductor laser bar 10 is inputted to a side surface of the core 31 of the optical fiber 30 via the core part 21 of the optical waveguide 20.

Abstract: A hollow waveguide has a metal-clad pipe having an inside metal layer and an outside metal layer, and a hollow region formed inside of the metal-clad pipe. The metal-clad pipe is formed by pressure-bonding metal pipes each of which is made of a metal material different from each other.

Abstract: An optical fiber includes a rare-earth element-added core for serving as a gain medium, and a cladding formed on a periphery of the core. Pump light propagated through the cladding is coupled into the core. The cladding is in an undulation shape in the longitudinal direction of the cladding. The undulation shape of the cladding is formed according to a grating period at which the pump light is totally reflected and propagated in the cladding. The core includes an undulation shape in a longitudinal direction of the core. The cladding includes an undulating inner cladding, and an outer cladding provided on a periphery of the inner cladding. The core and/or the cladding is circular or abnormally circular in its transverse cross section.

Abstract: A cladding is provided at an outer periphery of a solid-core doped with rare earth ions, and a metal layer is formed to be adjacent to the cladding to provide an optical fiber for a fiber laser device. The metal layer having an inner metal layer and an outer metal layer is disposed along an entire length of the optical fiber for a fiber laser device. An exciting light is incident to the optical fiber for a fiber laser device, and the exciting light is reflection-excited to emit a high power laser oscillation light. A monitoring current is constantly flown into the metal layer. When the disconnection of the optical fiber for a fiber laser device is detected based on the monitoring current, the energization of the optical fiber for a fiber laser device is stopped.

Abstract: A laser energy transmission optical fiber having an optical fiber main body which has a hollow-core region with a diameter greater than a wavelength of transmitted light, an inner clad region which has a solid portion with plurality of holes formed therein, and an outer clad region formed surrounding the inner clad region. The outer clad region has a refractive index lower than the solid portion of the inner clad region.

Abstract: To provide a low-cost, high reliability and high-powered operation enabled optical fiber laser, in the optical fiber laser for oscillating a laser light by introducing an excitation light for exciting the rare earth elements into the optical fiber doped partially by the rare earth elements, the optical fiber is wrapped around the base member, and one part of the outer circumferential area of the wrapped optical fiber is processed in order to form a flat surface, and one face of the prism is made contacted to the flat surface, and the excitation light is introduced to another surface of the prism.

Abstract: A laser energy transmission optical fiber having an optical fiber main body which has a hollow-core region with a diameter greater than a wavelength of transmitted light, an inner clad region which has a solid portion with plurality of holes formed therein, and an outer clad region formed surrounding the inner clad region. The outer clad region has a refractive index lower than the solid portion of the inner clad region.

Abstract: An optical fiber for a fiber laser has: a hollow core region; an inner cladding region having a plurality of holes that extend in a longitudinal direction of the optical fiber and surround the hollow core region; and an outer cladding region that surrounds the inner cladding region. The inner cladding region has a solid part that is made of a glass material into a part or all of which a rare earth element is doped, and the outer cladding region has a refractive index lower than that of the solid part of the inner cladding region.

Abstract: A hollow waveguide has a metal-clad pipe having an inside metal layer and an outside metal layer, and a hollow region formed inside of the metal-clad pipe. The metal-clad pipe is formed by pressure-bonding metal pipes each of which is made of a metal material different from each other.

Abstract: A gas detection method capable of solving the problem with respect to the operation at normal temperature that was impossible so far in the existent catalyst type sensor and detection with high sensitivity that was impossible by the light absorption type sensor. A multi-layered film formed of a first layer adsorbing a specified gas and a second layer having less adsorption are utilized as a detection film, and the detection film is disposed in the direction perpendicular to the optical channel and optically detects the change of stress caused in the detection film by gas adsorption as coupling loss. Alternatively, the stress generated in the detection film caused by gas adsorption is electrically detected by a piezoelectric element or capacitance element.

Abstract: A medical laser probe having a dielectric thin film which is coated on the inside wall of a metal pipe and is transparent at a wavelength band of a transmitted laser light is disclosed. The laser probe is detachable to be disposed and reused and satisfies the required characteristics such as low loss transmission, non-toxicity, mechanical strength, heat resistance, moisture resistance, resistance to chemicals, echonomical efficiency, easy-to-use, and the like.

Abstract: A solution of a metallic compound or a cyclic olefin polymer is introduced into a metallic pipe to deposit the solution onto the whole inner wall of the metallic pipe followed by heat treatment at a high temperature to dry and solidify the solution, thereby forming a dielectric layer. Thus, a metallic hollow waveguide is prepared which comprises a metallic pipe, a dielectric layer provided on the inner wall of the pipe, and a hollow region defined by the inner wall of the dielectric layer. The above constitution makes it possible to provide a highly reliable hollow waveguide which is usable in a broad waveband, for which a quartz optical fiber is unusable, causes no significant transmission loss, can be mass produced, and can be easily produced in a reduced diameter and in an increased length, and to provide a method of making the same.

Abstract: A polyimide resin layer is formed on an inner surface of a metal pipe or a non-metallic pipe having a metal thin film on an inner surface to provide an optical hollow waveguide. The polyimide resin layer is transparent relative to a wavelength band of a laser light transmitted through the optical hollow waveguide. The optical hollow waveguide is fabricated by supplying solution of polyimide precursor to a hollow internal of the metal pipe or the non-metallic pipe, and heating and drying the solution to provide a polyimide resin layer. The solution-supplying step and the solution-heating and drying step are repeated to increase a thickness of the polyimide resin layer up to a predetermined value.

Abstract: A radio frequency (RF) excited waveguide gas laser has a hollow wavegide defined by dielectric or lossy materials and metal electrodes coated by thin films with small absorptions so that the metal electrodes are separated from the filling gas and the waveguide loss is very low. With such thin films on the electrodes, a sealed-off, high-power, compact waveguide gas laser having an extended life is realized.

Abstract: A radio frequency (RF) excited waveguide gas laser has a hollow waveguide defined by dielectric or lossy materials and metal electrodes coated by thin films with small absorptions so that the metal electrodes are separated from the filling gas and the waveguide loss is very low. With such thin films on the electrodes, a sealed-off, high-power, compact waveguide gas laser having an extended life is realized.

Abstract: An optical waveguide comprising a layer formed on a substrate, having a mixed composition of silicon oxide and silicon nitride and having an arbitrary value of refractive index ranging between those of the silicon oxide and the silicon nitride. The layer of said mixed composition can be formed on the substrate to easily fabricate the optical waveguide of the present invention by conducting a sputtering method employing a Si target and controlling the composition of a sputtering gas composed of a mixture of N.sub.2 and O.sub.2 gases.