Showing papers by "Alwyn J. Seeds published in 1990"
TL;DR: The use of optically controlled devices to perform a range of circuit functions is reviewed in this article, where the optical control of amplifier performance is discussed and future directions for research in this area are discussed.
Abstract: The use of optically controlled devices to perform a range of circuit functions is reviewed. The optical control of amplifier performance is discussed. The optical control of two- and three-terminal oscillators and optically pumped mixers is discussed. Among the active devices treated are Gunn and IMPATT oscillators; MESFET and HEMT amplifiers, oscillators, and mixtures; and diode mixers. Future directions for research in this area are discussed. >
217 citations
TL;DR: In this paper, the maximum laser linewidth and loop gain in an optical phase-locked loop (OPLL) are calculated as a function of loop delay and filter bandwidth, using a cycle-slipping criterion.
Abstract: Maximum laser linewidth and loop gain in an optical phase-locked loop (OPLL) are calculated as a function of loop delay and filter bandwidth, using a cycle-slipping criterion. It is shown that a loop delay of less than 2 ns would permit the realisation of OPLLs using the recently reported submegahertz linewidth monolithic tunable semiconductor lasers.
96 citations
TL;DR: In this paper, a beam forming technique for use in optically controlled phased arrays is presented, which is the optical equivalent of the microwave Huggins phase shifter, using two optical fiber networks to produce a beam having independently specified frequency and aperture phase slope.
Abstract: A new beam forming technique for use in optically controlled phased arrays is presented. The system, which is the optical equivalent of the microwave Huggins phase shifter, uses two optical fibre networks to produce a beam having independently specified frequency and aperture phase slope. The theory of the system is presented together with experimental results for a system implemented at the L-band.
16 citations
08 May 1990
TL;DR: In this article, a review of current European work on optical feeds is presented, ranging from systems demonstrator work and optical signal distribution networks to research studies on phased array beam formers using coherent optical techniques.
Abstract: A review is presented of current European work on optical feeds, ranging from systems demonstrator work on optical signal distribution networks to research studies on phased array beam formers using coherent optical techniques The attractions of optical signal feeds for phases array antennas are becoming accepted, and it is possible to control groups of 10-200 elements from a single laser source In Europe early application to space-based phased arrays is expected However, the advantages of reduced mass and improved electromagnetic compatibility are also important in naval applications Much development work on optical sources and detectors remains to be done to improve the efficiency of the optical-electrical interface Optical beam forming is a topic of considerable current research interest, and both coherent and noncoherent techniques are likely to find system applications In the longer term direct optical control of microwave devices would permit further reductions in array complexity provided the problems of device design to give efficient optical coupling can be overcome >
9 citations
26 Oct 1990
TL;DR: In this article, a new beam forming technique for use in optically controlled phased array antennas is presented, which uses two optical fiber networks to produce a beam having independently specified frequency and aperture phase slope.
Abstract: Presents a new beam forming technique for use in optically controlled phased array antennas The system uses two optical fibre networks to produce a beam having independently specified frequency and aperture phase slope The theory of the system is presented together with a description of the experimental implementation and results for a system operating at L-band
2 citations