William K. Marshall

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An exact result for the spectral density of intensity variations that occur after propagation of ergodic light in a medium having lowest-order-only group-velocity dispersion is obtained and applied to the problem of semiconductor laser phase noise to intensity noise conversion in a single-mode optical fiber. It is shown that the intensity spectrum after(More)
— When the series resistance is separated and treated as a separate element, it is shown that losses in an inductor require the ratio of the flux to mmf in the core to be frequency dependent. For small-signal operation, this dependence leads to a circuit model composed of a lossless inductor and a resistor in parallel, both of which are frequency dependent.(More)
In vivo gene transfer to the ischemic heart via electroporation holds promise as a potential therapeutic approach for the treatment of heart disease. In the current study, we investigated the use of in vivo electroporation for gene transfer using three different penetrating electrodes and one non-penetrating electrode. The hearts of adult male swine were(More)
—The spectral density of the optical intensity which results after modulated, noisy light is propagated in dispersive single-mode fiber is investigated theoretically and experimentally. An exact general result is obtained for the case of lowest-order-only group velocity dispersion and is applied to light from a 1550-nm distributed-feedback semiconductor(More)
We report on the demonstration of a high finesse micro-optomechanical system and identify potential applications ranging from optical cooling to weak force detection to massive quantum superpositions. The system consists of a high quality diameter flat dielectric mirror cut from a larger substrate with a focused ion beam and attached to an atomic force(More)
— Measurements of small-signal intensity modulation from direct-modulated distributed feedback (DFB) semiconductor lasers after propagation in dispersive fiber have previously been used to extract intrinsic laser chirp parameters such as linewidth enhancement factor and crossover frequency. Here, we demonstrate that the simple rate equations do not(More)
We describe a method of characterizing high-order polarization mode dispersion (PMD). Using a new expansion to approximate the Jones matrix of a polarization-dispersive medium, we study the length dependence of high-order PMD to the fourth order. A simple rule for the asymptotic behavior of PMD for short and long fibers is found. It is also shown that, in(More)
The effect of dispersive, linear propagation ͑e.g., in single-mode optical fiber͒ on the intensity noise from semiconductor lasers is investigated. Relations between the frequency and amplitude noise variations of semiconductor lasers are obtained from the laser rate equations and used to calculate the change in the relative intensity noise ͑RIN͒ spectrum(More)
Integration of large quantities of wind generation into existing power systems is a topic of concern and much study throughout the world. The New Brunswick System Operator completed a preliminary study of integration issues in the summer of 2005 for large scale wind development in the Maritimes Area of northeast North America. The study simulates wind(More)
The stability margin of an audio power amplifier is reduced by a pole in the loopgain transfer function caused by shunt capacitance in the loudspeaker load. The problem is most severe in amplifiers with output stages that have a high output impedance before feedback. Because MOSFET devices can have an output impedance that is much higher than BJT devices,(More)