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Volume 24, Issue 12
Displaying 1-13 of 13 articles from this issue
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Tadashi ARUGA1996 Volume 24 Issue 12 Pages 1263
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDownload PDF (138K) -
An Overview[in Japanese], [in Japanese], Hiroshi IWASAWA1996 Volume 24 Issue 12 Pages 1264-1271
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSSpace optical communication is expected to play an important role in high-speed and large capacity data links for future global communications and space activities. In the paper, the background and trends in this promising field are presented as well as a scope of its technological basis. Optical communication experiments which have been recently performed by Communications Research Laboratory using ground-to-satellite links are also described.View full abstractDownload PDF (1135K) -
James LESH, Leslie DEUTSCH, Charles EDWARDS1996 Volume 24 Issue 12 Pages 1272-1277
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA recent study of deep space telecommunication systems was performed in support of NASA's Mission to the Solar System planning activity. The results of this study show that high bandwidth communications (greater than 1 Mbps) are feasible at high-value planetary targets provided there are investments in the ground and spacecraft communication infrastructure. These targets include Mars, Jupiter, and Neptune. Optical communications is a key enabling technology for achieving the higher data rates. This work was then extended to consider solutions to extreme deep space (beyond 100AU) communications. Communications data rates between 10 and 100 Kbps should be achievable from as far as 1, 000AU within 25 years. The technologies, infrastructure enhancements, and resulting performance capabilities are discussed in this paper.View full abstractDownload PDF (698K) -
Nobuo TAKEUCHI1996 Volume 24 Issue 12 Pages 1278-1284
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe earth observation by satellite becomes more important with the increase of attention to the global environment. The satellite observation started with the weather, a field of atmospheric science, and the satellite weather observation has become operational. However, the recent development of satellite sensors was on the image sensors for land and ocean. Atmospheric sensors are most important among future sensors to be developed for the EOS(Earth Observing System) program. Especially, laser altimeter and lidar (laser radar) gather a lot of attention, because of the ability of direct range measurement and the good vertical range resolution. In this article, the history of space lidar project by NASA and ESA, space shuttle lidar experiment (LITE), and space lidar program will be presented as well as the long-path absorption between the earth and the satellite.View full abstractDownload PDF (845K) -
Laser Engineering for Multi-Beam ApplicationsJack L. BUFTON, BLAIR BLAIR1996 Volume 24 Issue 12 Pages 1285-1292
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe relatively new technique of laser altimetry, the measurement of Earth surface elevation by timing the propagation interval and digitizing the echo of short laser pulses, is in transition from an airborne remote sensing activity to space-based measurements of global topography. Space-based laser altimeters not only measure distance to the Earth's surface along the nadir track of a host spacecraft, but conduct a surface lidar investigation to reveal the complex shapes of land surface and its vegetation cover. Multi-beam concepts extend the coverage and accuracy of space applications of laser altimetry.View full abstractDownload PDF (1101K) -
Tetsuya MIYAZAKI, Keizo INAGAKI, Yoshio KARASAWA, Hideyuki INOMATA1996 Volume 24 Issue 12 Pages 1293-1300
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSWe examine 2.5Gbit/s and 5Gbit/s transmission characteristics of Nd-doped fiber amplifier (NDFA) at 1.064m as a booster amplifier and a pre-amplifier in the intersatellite optical communication links. It is found that the combination of the booster amplifier (100mW output) and the pre-amplifier (3dB noise figure) employing the NDFAs can establish giga-bit optical links between low-earth-orbit satellites with several thousands kilo-meters. Features of the NDFA such as high power conversion efficiency (52%) and low noise and high gain amplification characteristics, spatial-distortion-free beam output, polarization independence and vibration-free will allow it to replace the solid-state laser amplifier in free-space applications.View full abstractDownload PDF (935K) -
as a Part of Future Space InfrastructureTomohiro ARAKI, Yasumasa HISADA1996 Volume 24 Issue 12 Pages 1301-1307
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSWe would like to report our research and development on Optical Inter-orbit Communication (Optical IOC) technology. NASDA has been developing Optical Inter-orbit Communications Engineering Test Satellite (OICETS) for a demonstration of Acquisition, Tracking, and Pointing (ATP) technology on orbit, as a key technical problem of Optical IOC, with ESA satellite ARTEMIS. Moreover, we have been conducting researchers on 1W-class high power optical amplifiers, namely Erbium doped fiver amplifiers (EDFA, λ=1550nm) and Neodymium doped fiber amplifiers (NDFA, λ=1060nm), to establish higher data rate (> 1Gbps) technology and much-smaller equipment technology, which will satisfy the requirements of future space activities. We already achieved 345mW amplification of double-clad NDFA (DC-NDFA). In this paper, we report our latest progress on fiber amplifiers. In addition, we discuss the results of trial manufacture of InGaAs-QD as an ATP sensor for wavelengths of NDFA and EDFA. The future of Optical IOC technology is also discussed.View full abstractDownload PDF (815K) -
Hiroo YUGAMI, Hitoshi NAITO, Haruo Arashi1996 Volume 24 Issue 12 Pages 1308-1314
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPower transmission by high power lasers is one of the most attractive methods for energy supply system in space. This paper describes the results of solar-pumped solid state lasers developed by the author's group, and some concepts of laser power beaming proposed in USA and Japan. Finally, we introduce the proposal on the space experiment of laser power beaming at Japanese Experiment Module (JEM) on the space station.View full abstractDownload PDF (865K) -
Michio NAKAYAMA, Atsuko WATANABE, Tadashi TAKAHASHI, Toshio SATOH, Yos ...1996 Volume 24 Issue 12 Pages 1315-1323
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA frequency stabilized Helium-Neon laser was developed to be launched into space and used as a calibration light source in a Fourier-transform interferometer. It is a simple Helium-Neon laser constructed with a minimum number of components and without any active resonator length controls to achieve both frequency stability and operating reliability in the space environment. Tests indicate a short-term frequency vs. temperature stability of the order of 10-8/degreeC, a frequency repeatability of 5×10-9, and an estimated reliability of 0.94 for 3 years of operation period, all of which satisfy the mission requirements.View full abstractDownload PDF (1112K) -
Keizo NAKAGAWA, Yoshiaki SUZUKI, Takashi JONO1996 Volume 24 Issue 12 Pages 1324-1331
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe laser diodes (LD) are installed on the Optical Inter-orbit Communications Engineering Test Satellite (OICETS). These LDs are used for communications from OICETS to the geostationary satellite, ARTEMIS (Advanced Relay and Technology Mission Satellite) manufactured by European Space Agency (ESA). Through the screening, evaluation test and qualification test, the LDs for flight could be selected. The evaluation and qualification test flow and the results of the tests are described in this paper.View full abstractDownload PDF (838K) -
Do-Hyun PARK, Gi-Jung NAM, Kyu-Haeng LEE, Sang-Cheon KIM, Hoon SHIM, S ...1996 Volume 24 Issue 12 Pages 1332-1336
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe effects of the saturable absorber absorption on the pulse duration and stability of active-passively mode-locked YAlO3:Nd3+ laser were investigated. The optimum conditions for energy stability and pulse duration were obtained at the absorption coefficient of α0 = 10.5 cm-1. The energy stability of the steady-state part of the pulse train, containing approximately 60 pulses, was achieved to be less than ±1% r.m.s.. The nonlinear behavior of the passive negative feedback element was also observed.View full abstractDownload PDF (603K) -
Fumiyoshi KUWASHIMA, Iwao KITAZIMA, Hiroshi IWASAWA1996 Volume 24 Issue 12 Pages 1337-1343
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThis paper reports the first observation on the chaotic emission from a class A laser. A single mode He-Ne (6328Å) laser which had an external mirror with a PZT was used. Varying the vibrational frequency of the PZT, time series of laser output power were observed, from which the strange attractors in the phase space, finite correlation dimension, positive Lyapunov exponents were obtained. As results, around 100Hz of the PZT frequency, the chaotic emission was recognized.View full abstractDownload PDF (735K) -
Noboru Nakatani1996 Volume 24 Issue 12 Pages 1344-1349
Published: December 25, 1996
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThis paper describes a system for measuring the flow velocity and temperature of gases by means of a photothermal effect. We used a differential interferometer for suppressing the influence of external disturbances and detecting small phase variation caused by the photothermal effect. The operating point is set at the maximum inclination point of fringe intensity curve by controlling the position of a photodetector. This system uses two focal spots as measuring points of time-of-flight method. The interferometer signals are analyzed for obtaining propagation velocity of photoacoustic pulse and velocity of photothermal puff. Using jets of a gas mixture of nitrogen and ethylene, we confirmed that this measurement system is useful to measure the flow velocity and temperature.View full abstractDownload PDF (689K)
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