The transmission of chemical oxygen-iodine laser (COIL) emission through several kinds of multimode quartz optical fiber is measured in order to explore the applicability of COILs for the extraction of natural resources. The minimum transmission loss through these fibers is 0.64 dB/km, and high-power transmission for a distance of kilometers is shown to be feasible. Laser emission at an average input power of 1 kW is successfully transmitted through a multimode optical fiber for a distance of 1 km with an efficiency of 80%.
Chemical oxygen-iodine laser (COIL) has a great potential for applications such as decommissioning and dismantlement (D&D) of nuclear reactor, rock destruction and removal and extraction of a natural resource (Methane hydrate) because of the unique characteristics such as power scalability, high optical beam quality and optical fiber beam. Five-kilowatt Chemical oxygen-iodine laser (COIL) test facility has been developed. The chemical efficiency of 27% has been demonstrated with a moderate beam quality for optical fiber coupling. Our research program contains conventional/ejector-COIL scheme, Jet-SOG/Mist-SOG optimization, fiber delivery and long-term operation.
Chemical oxygen-iodine laser (COIL) has a great potential for applications such as decommissioning and dismantlement (D&D) of nuclear reactor, rock destruction and removal and extraction of a natural resource (Methane hydrate) because of the unique characteristics such as power scalability, high optical beam quality and optical fiber beam. Five-kilowatt Chemical oxygen-iodine laser (COIL) test facility has been developed. The chemical efficiency of 27% has been demonstrated with a moderate beam quality for optical fiber coupling. Our research program contains conventional/ejector-COIL scheme, Jet-SOG/Mist-SOG optimization, fiber delivery and long-term operation.
Pulsed oscillation of chemical oxygen-iodine laser, which is comprised of a pulsed singlet oxygen generator (SOG) and a photolytic iodine laser, is studied. This scheme allows one to produce a large aperture and high-pressure laser medium while maintaining a minimum degradation of stored energy by water vapor. The experimental apparatus consists of a porous pipe SOG, an iodine donor (CH3I) injector, a flash lamp and an optical resonator. Laser oscillation experiments are conducted and the operational characteristics of the apparatus are investigated. Pulse duration is inversely proportional to the iodine donor concentration as expected. The oscillation capability for different iodine donors is studied and it is concluded that the iodine donors containing fluorine are not suitable for the proposed scheme. Unfavorable chemical dissociation of iodate, which was observed in the previous study, is avoided by the optimization of the iodine donor injection and flash exposure timings. Maximum output energy of 730mJ with pulse duration of 65μm is obtained.
KEYWORDS: Diffusers, Throat, Iodine, Chemical oxygen iodine lasers, Laser resonators, Chemical analysis, Chemical reactions, Molecules, Laser development, Chemical lasers
Optimization of iodine injection scheme was conducted in Miki Pulley Co., Ltd. using CFD approach. Variation of the mixing speed as a function of an I2 jet penetration depth, nozzle expansion ratio, and I2 injection point are analyzed. It was found that the inherent geometry of our nozzle and I2 injector affects the I2 mixing process. Influence of a backpressure to the cavity flow condition was also investigated in order to estimate the pressure recovery capability of our diffuser. The normal shock based diffuser efficiency for Mach=2.7 flow was 54.5%.
Miki Pulley has pursued the development of a prototype COIL module for field and industrial applications since its transfer from Tokai University in 2000. The test module has already been constructed in our laboratory. The current status of the development is presented. The achieved chemical efficiency was 17.5% at the chlorine flow rate of 13.2mol/min. The corresponding laser power was 3.5kW.
Laser medium parameters of multi-kW grid nozzle supersonic Chemical Oxygen Iodine Laser (COIL) were experimentally studied. Small-signal gain (SSG) diagnostics was done by a narrow line width tunable laser by scanning 1 GHz range around (2P1/2 ) - (2P3/2) spin-orbit transition line of atomic iodine. SSG was investigated as a function of Mach number and gas flow rates. Modeling of gain for different flow conditions was done as well. Multi-kW COIL device was recently developed in Miki Pulley Co., Ltd. (Japan) and has 37.5 cm length of active medium.
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