Showing papers by "Ulrich Johann published in 1991"
01 May 1991
TL;DR: In this article, the authors have evaluated and breadboarded the pointing/acquisition/tracking subsystem breadboard, an optical Costas-loop receiver, and advanced Nd:YAG transmitter technology.
Abstract: Germany's Solid State Laser Communications in Space, or 'SOLACOS' program has undertaken the terrestrial verification of coherent laser communications systems based on Nd:YAG lasers, giving attention to the evaluation and breadboarding of critical components and subsystems. These components encompass the pointing/acquisition/tracking subsystem breadboard, an optical Costas-loop receiver, and advanced Nd:YAG transmitter technology. Results are presented for subsystem components developed to date.
8 citations
01 May 1991
TL;DR: In this paper, a diode-pumped Nd:YAG laser transmitter laboratory breadboard is proposed for space applications, which can not only furnish the data carrier but also serve as a tracking reference and (in conjunction with a boost amplifier) as a beacon.
Abstract: A design concept suitable for space applications is proposed on the basis of a diode-pumped Nd:YAG laser transmitter laboratory breadboard; this transmitter must not only furnish the data carrier but also serve as a tracking reference and (in conjunction with a boost amplifier) as a beacon for receiver-station acquisition. The diffraction-limited beam is generated with 6.3-percent electrical-to-optical conversion efficiency. The proposed space communications system will incorporate astigmatically-focused stacked-laser diodes for continuous reliable operation over the course of seven years.
6 citations
01 May 1991
TL;DR: The SILEX experimental program is concerned with demonstrating the technologies of an optical communications link between two satellites; in order to expand system capabilities to the high data rates required for future LEO-GEO interorbit links, a detailed design study has been conducted for a system predicated on diode-pumped Nd:YAG laser technology.
Abstract: The SILEX experimental program is concerned with demonstrating the technologies of an optical communications link between two satellites; in order to expand system capabilities to the high data rates required for future LEO-GEO interorbit links, a detailed design study has been conducted for a system predicated on diode-pumped Nd:YAG laser technology. Even with telescopes whose apertures are less than 10 cm on the LEO satellite, and transmitter powers of less than 1 W, system transmission performance is greater than 1 Gbit/sec.
5 citations
01 May 1991
TL;DR: In this paper, a fast optical fiber based tracking detector was developed, tested and characterized as a cmponent for a coherent Nd:YAG laser space communication system, where a freely suspended and conductively coated singlemode fiber end is excited to a fast small amplitude conical motion when electrostatically deflected close to its mechanical resonances by the capacitive action of one or two electrodes.
Abstract: A fast optical fiber based tracking detector has been developed, tested and characterized as a cmponent for a coherent Nd:YAG laser space communication system. A freely suspended and conductively coated single-mode fiber end is excited to a fast small amplitude conical motion when electrostatically deflected close to its mechanical resonances by the capacitive action of one or two electrodes. The induced intensity modulation of the laser light coupled into the fiber is phase-sensitively detected (optionally after coherent amplification) and used for spatial input coupling optimization in a servo loop steering the laser beam. Modulation frequencies higher than 10 kHz are feasible in a very compact, rugged device at low power consumption. The device can also be modified for scanning of a transmitter beam.
4 citations
01 Jun 1991
TL;DR: In this paper, a detailed design study for an advanced optical communication system based on diode-pumped Nd:YAG laser technology performed within the framework of an ESA contract is presented.
Abstract: Results of a detailed design study for an advanced optical communication system based on diode-pumped Nd:YAG laser technology performed within the framework of an ESA contract are presented. Emphasis is placed on reaching a low mass/low power design with sufficient maturity to develop space-qualified systems by the middle of this decade. The systems employ coherent PSK homodyne Costas loop receiver technology on the high data rate links, while QPPM modulation and direct detection is foreseen on the 25-Mb/s link. For the intersatellite duplex link, the same communication laser line is used for both directions, thus allowing multiple connections within a given satellite network. With 15-cm aperture telescopes on both terminals, maximum transmitter power is 500 mW for the 650 Mb/s link. Overall communication terminal mass is in the 70-80 kg range, and typical power consumption is 120-160 W.
3 citations