Abstract: A fiber laser device contains a first optical fiber of a double-clad type in which optical resonance of an infrared laser light takes place inside a core with Pr3+and Yb3+added thereto to generate a light of a wavelength of about 630 nm, a second optical fiber of a double-clad type in which optical resonance of an infrared laser light takes place inside a core with Pr3+and Yb3+added thereto to generate a light of a wavelength of about 690 nm, and a third optical fiber in which optical resonance of the lights from the first and second optical fibers takes place inside a core with Tm3+added thereto to generate a light of a wavelength of about 450 nm, and the core diameter of the third optical fiber is made substantially equal to the spot diameters of the lights from the first and second optical fibers.

Abstract: An optical module apparatus comprises a first optical element, a first member which holds the first optical element, a second optical element placed near the first optical element, and a second member which holds the second optical element. A plurality of wedges are arranged at a plurality of positions between the first member and the second member thereby to hold the relative positions of the first optical element and the second optical element.

Abstract: A semiconductor laser module comprising, a semiconductor laser element, an electronic cooling element configured to allow heat from the semiconductor laser element to be transmitted thereto, a heat sink configured to allow the heat which is transmitted to the electronic cooling element to be released, an optical system configured to conduct a laser beam which is emitted from the semiconductor laser element to an optical fiber cable, and a heat resistance section configured to transmit the heat of the optical system to the electronic cooling element, having a heat resistance greater than a heat resistance when the heat of the semiconductor laser element is transmitted to the electronic cooling element.

Abstract: An optical fiber module according to the present invention holds an optical fiber made by an ordinary manufacturing means between two glass substrates with a coefficient of thermal expansion approximately equal to that of a cladding material of the optical fiber, these substrates being heated up to a predetermined temperature higher than a glass transition temperature of the optical fiber, and pressurized by a predetermined pressure to taper the optical fiber, thereby improving the coupling with a light-emitting element such as a semiconductor laser.

Abstract: An optical module apparatus comprises a first optical element, a first member which holds the first optical element, a second optical element placed near the first optical element, and a second member which holds the second optical element. A plurality of wedges are arranged at a plurality of positions between the first member and the second member thereby to hold the relative positions of the first optical element and the second optical element.

Abstract: An optical fiber, having a fiber cladding and a fiber core doped with laser active material, is embedded in an optical waveguide core having a refractive index almost equal to that of the optical fiber cladding, and pumping light is guided, in a side pumping manner, from the semiconductor laser via the light-guiding section. The guided pumping light is absorbed by the laser active material, as it propagates and moves around in the optical waveguide core in a fixed direction. Because the optical waveguide core is ring-shaped and enclosed by the optical waveguide cladding having a low refractive index, the rest of the guided pumping light propagates and moves around in the optical waveguide core again. Therefore, a laser active material in the optical fiber core can be pumped efficiently.

Abstract: A method of drilling a well by utilizing AE/MA measurement which has the steps of monitoring an AE wave emitted at the periphery of the well, and drilling the well without lost circulation by providing lost circulation preventing means in the well if the energy of the AE wave emitted at the periphery of the well increases. Thus, the method can confirm a lost circulation layer, i.e., the size, the place and the direction of the underground crack to further determine whether further drilling is necessary or not.

Abstract: A method of collecting geothermal steam using Acoustic Emission Microseismic Activity (AE/MA) measurement includes the steps of (a) surveying an AE wave emitted in subsurface cracks to obtain the size of a water permeable geothermal reservoir by analyzing the AE wave, (b) further surveying the AE wave emitted in and around the periphery of the geothermal reservoir, (c) operating the wellhead valve of the geothermal well connected with the geothermal reservoir, thereby extending or preventing the extension of the geothermal reservoir in accordance with the information obtained in step (a) and/or step (b), thereby stably obtaining a predetermined quantity of steam of high quality. Thus, the method can stably obtain geothermal steam of high quality by accurately surveying or monitoring subsurface cracks by an AE measurement technique and propagating the subsurface cracks or suppressing the propagation of the cracks.

Abstract: An integration sphere type turbidimeter having a cylindrical sample cell passing through an integration sphere and an optical system disposed so as to permit a collimated beam of light to be projected into the sample cell from one end to the other end thereof, whereby the diffused rays of light produced by the dispersed particles in the sample liquid are substantially completely picked up by the integration sphere.

Abstract: Disclosed herein is a device for wiping the optical window of a sample cell in a turbidimeter or other optical instrument for examining a liquid sample, which device comprises a wiper adapted to be inserted into the inner surface of the sample cell and rotated around its axis so as to clean the optical window quickly and easily of defiling matter adhering to the optical window.