Showing papers on "Parametric oscillator published in 1969"
TL;DR: In this paper, a singly resonant optical parametric oscillator (SRO) is used to tune a high power, pulsed source and tune it to a predetermined desired frequency, and radiation of that frequency is injected into a mode of the SRO from a stabilized, low power injection source.
Abstract: A singly resonant optical parametric oscillator (SRO) is pumped by a high power, pulsed source and is tuned approximately to a predetermined desired frequency. Radiation of that frequency is injected into a mode of the SRO from a stabilized, low-power injection source. The output of the SRO is a pulsed, high-power signal with frequency equal to the predetermined frequency to a high degree of accuracy.
99 citations
TL;DR: In this article, a single mode oscillation of a pulsed singly resonant optical parametric oscillator was achieved by placing a tilted mode selecting Fabry-Perot etalon inside the oscillator cavity.
Abstract: Single mode oscillation of a pulsed singly resonant optical parametric oscillator was achieved by placing a tilted mode selecting Fabry‐Perot etalon inside the oscillator cavity. The output power was 25% of that obtained in multimode oscillation without the etalon. Good agreement was obtained between observed and expected spectral width both with and without the etalon inside the optical cavity.
57 citations
TL;DR: In this paper, the effect of noise on the microwave-induced steps in the current-voltage characteristic of a Josephson junction is investigated theoretically, and the dynamic resistance of a step is obtained in the limit that the capacitance of the junction is small.
Abstract: The effect of noise on the microwave-induced steps in the current-voltage characteristic of a Josephson junction is investigated theoretically. The dynamic resistance of a step is obtained in the limit that the capacitance of the junction is small. The phase fluctuations of the junction are greatly reduced in the presence of the microwave signal, and the dynamic resistance can be extremely small.
46 citations
TL;DR: In this paper, the authors present an analysis of the steady-state oscillation of a doubly resonant optical parametric oscillator in which there are no power-dependent reflections of pump power from the oscillator cavity.
Abstract: We present an analysis of the steady-state oscillation of a doubly resonant optical parametric oscillator in which there are no power-dependent reflections of pump power from the oscillator cavity. There is no limiting of the pump power passing through such an oscillator and 100-percent conversion efficiency is obtained for pumping four times threshold. Previous experiments are discussed in light of these results.
32 citations
TL;DR: In this paper, the operation of an optical parametric oscillator which is directly pumped by the 1.06μ output of a continuously pumped, repetitively Q-switched Nd:YAG laser is described.
Abstract: The operation of an optical parametric oscillator which is directly pumped by the 1.06‐μ output of a continuously pumped, repetitively Q‐switched Nd:YAG laser is described. The oscillator uses a 3‐mm lithium niobate crystal in a non−90° orientation as the nonlinear material. 17 mW of average output power at 2 μ have been obtained giving an oscillator conversion efficiency of 8%. Measurements are also reported of pump power threshold, pump depletion, and wavelength tuning of the oscillator. No optically induced index inhomogeneities were observed in the lithium niobate.
27 citations
TL;DR: In this article, the performance of a continuous wave millimeter-wave IMPATT diode oscillator with a wide-band tunability is reported, where the diode is mounted in an iris wafer circuit; its oscillation frequency can be modulated either by a varactor diode or by direct modulation of the IMPATT bias current.
Abstract: In this paper we report the performance of a continuous wave millimeter-wave IMPATT diode oscillator with a wide-band tunability. The diode is mounted in an iris wafer circuit; its oscillation frequency can be modulated either by a varactor diode or by direct modulation of the IMPATT diode bias current. The oscillator has been successfully used as a millimeter-wave frequency deviator in an experimental pulse code modulation millimeter-wave system. We also report detailed measurements on subharmonic frequencies in IMPATT diode oscillators. Experimental results show that wide frequency tunability can be obtained with a circuit which provides an “idler” resonance at one-half the fundamental transit-time frequency. The results also show that by providing “idler” resonances at both the transit-time frequency and at one-half of the transit-time, the oscillation at 3/2 the transit-time frequency is enhanced and yields a useful output power of 2 mW at 86 GHz.
27 citations
Patent•
20 Mar 1969TL;DR: In this paper, the optical cavity of a pulsed optical parametric oscillator was shown to be resonant for idler radiation and nonresonant for the signal, and various arrangements to affect tuning of the oscillators were disclosed.
Abstract: Continuous-wave and pulsed optical parametric oscillators are disclosed in each of which the optical cavity is resonant for the idler and nonresonant for the signal. Two of the disclosed oscillators employ a nonlinear crystal placed within the pumping laser resonator; and at least one of the pump reflectors is highly transmitting for the signal radiation. One of the oscillators is designed so that oscillation may be achieved on a continuous-wave basis; the other is designed for pulsed or continuous-wave mode-locked operation in which the output consists of a train of short pulses. The other disclosed oscillator employs a nonlinear crystal in a cavity resonant for idler radiation and external to the cavity of the pumping laser. Various arrangements to affect tuning of the oscillators are disclosed.
21 citations
Patent•
20 Mar 1969TL;DR: In this paper, the parametric oscillators are characterized by a common region in which the nonlinear optical medium is disposed, and the first and second ring resonators are separately tunable to resonate the signal and idler, respectively.
Abstract: In the parametric oscillators disclosed, first and second ring resonators are disposed to pass pumping radiation in one direction only and are characterized by a common region in which the nonlinear optical medium is disposed. The first and second ring resonators are separately tunable to resonate the signal and idler, respectively.
21 citations
TL;DR: In this paper, a visible ring-cavity parametric oscillator has been constructed and pump depletions of 60% have been observed, which can result from the optical isolation provided by the ring.
Abstract: A cw visible ring‐cavity parametric oscillator has been constructed and pump depletions of 60% have been observed. The experiment verified the increased conversion efficiency predicted for a parametric oscillator operating without a back‐generated pump wave, and also showed the improved stability which can result from the optical isolation provided by the ring‐cavity configuration.
20 citations
Patent•
10 Oct 1969
TL;DR: In this article, the frequency of the radar was modulated or swept by enclosing the transferred electron oscillator within a ferrite collar, whereby changing the applied voltage to the transceiver voltage changes the frequency.
Abstract: A radar apparatus comprised of a transferred electron oscillator in association with a cavity resonant at the frequency of oscillation of the transferred electron oscillator. A mixing diode in the signal path between the transferred electron oscillator and a transmit/receive aerial yields a difference output. The frequency of the radar may be modulated or swept by enclosing the transferred electron oscillator within a ferrite collar whereby changing the applied voltage to the transferred electron oscillator changes the frequency of the radar.
14 citations
Patent•
04 Mar 1969
TL;DR: In this article, the control fluid flow rate of the OSCILLATOR is modelled as a function of the control flow rate, which is used as a measure of the severity of negative feedback.
Abstract: THE FREQUENCY OF NEGATIVE FEEDBACK TYPE FLUIDIC OSCILLATOR IS RENDERED VARIABLE BY INTRODUCING CONTROL FLUID FLOW TO EITHER AID OR OPPOSE THE FEEDBACK FLOW. THE CONTROL FLUID FLOWS ADJCENT, ABOUT OR WITHIN THE FEEDBACK FLUID IN AN ENLARGED SECTION OF THE FEEDBACK PASSAGE, AND MAY HVE A VARIABLE FLOW RATE WHICH FREQUENCY-MODULATES THE OSCILLATOR OUTPUT SIGNAL. THE OSCILLATOR MAY BE EMPLOYEED AS A FLOW SENSOR WHEN THE CONTROL FLUID IS SUPPLIED FROM THE FLOW BEING MONITORED. ALTERNATELY, IF THE ENLARGED SECTION OF THE FEEDBACK PASSAGE IS CURVED ABOUT A PREDETERMINED AXIS, ROTATION OF THE SYSTEM ABOUT THAT AXIS INTRODUCES CONTROL FLOW VARIATIONS WHICH VARY THE OSCILLATOR FREQUENCY AS A FUNCTION OF ANGULAR ACCELERATION OD THE SYSTEM ABOUT THAT AXIS.
TL;DR: In this paper, a simple current-to-frequency converter was developed which works directly with photomultiplier currents, and it has full scale input current ranges of 3×10−10 to 3× 10−6 A.
Abstract: A simple current‐to‐frequency converter has been developed which works directly with photomultiplier currents. It has full scale input current ranges of 3×10−10 to 3×10−6 A. The feedback pulse is a square pulse that is clocked on and off by a continuously running oscillator. Drift in the oscillator frequency is compensated if the oscillator also serves as the time base of the counter used to count the pulses. With oscillator frequencies up to and including 20 kHz the linearity is 0.01% or better and the drift less than 0.01% of full scale per hour.
Patent•
26 May 1969
TL;DR: In this article, a first high frequency stable oscillator is used to control a second lower frequency oscillator by the method of sensing the attainment of a peak value of one of the oscillating parameters of the second oscillator, applying a constraint to that parameter to inhibit temporarily the oscillation of the first oscillator.
Abstract: A first high frequency stable oscillator is used to control a second lower frequency oscillator by the method of sensing the attainment of a peak value of one of the oscillating parameters of the second oscillator, applying a constraint to that parameter to inhibit temporarily the oscillation of the second oscillator, and releasing the constraint when the first oscillator next reaches a datum position in its cycle of oscillation.
Patent•
08 May 1969TL;DR: In this paper, a peak detector circuit is used to provide a control voltage proportional to the highest peak of the oscillator, which is applied to a chroma amplifier stage for varying the gain in accordance with varying oscillator amplitude.
Abstract: Automatic chroma control circuitry employs a peak detector circuit, operated from a chroma oscillator configuration, which oscillator exhibits a varying amplitude response determined by a narrow band filter included in an AC feedback path for the oscillator and arranged to selectively filter signal frequencies within the narrow band-pass as coupled thereto during the oscillatory burst interval. The band-pass filtered signals, including noise components serving to vary the peak amplitude of the oscillator cause the detector to provide at an output a control voltage proportional to the highest peak of the oscillator. This control voltage is applied to a chroma amplifier stage for varying the gain in accordance with varying oscillator amplitude.
TL;DR: In this article, the statistical properties of a parametric amplifier and a frequency converter are studied by means of quantum mechanical methods, where the Schrodinger picture and the P-representation of the density matrix are used.
Abstract: The statistical properties of a parametric amplifier and a frequency converter are studied by means of quantum mechanical methods. The Schrodinger picture and the P-representation of the density matrix are used. Carrying out the Fourier transformation of the Liouville equation a partial differential equation for a generating function is obtained. The inverse Fourier transform of a solution of this equation is a time-dependent P-representationPN(α1,α2,t). For the parametric amplifier a relation is derived which enables us to compute the functionPA(α1,α2,t) = =1π is shown thatPA is classical distribution ifPN(α1,α2,0) is a positive distribution, while the P-representationPN(α1,α2,t) need not exist as a distribution and the P-representationPN(α1,α2,t) for the parametric frequency converter is constant along classical trajectories.
TL;DR: In this paper, a method to lock the output frequency of an optical parametric oscillator to an absorbing atomic transition was proposed, where the effective linewidth of the oscillator becomes approximately that of the absorbing transition.
Abstract: A method to lock the output frequency of an optical parametric oscillator to an absorbing atomic transition is proposed. The effective linewidth of the oscillator becomes approximately that of the absorbing transition.
Patent•
16 Jun 1969TL;DR: In this article, a microwave oscillator circuit for a high-power high-efficiency negative-resistance bulk effect device is described, which includes a half-wavelength open-circuited length of transmission line provided with variable lumped capacitors at opposite ends thereof.
Abstract: A microwave oscillator circuit for a high-power high-efficiency negative-resistance bulk-effect device is disclosed. The circuit includes a half-wavelength open-circuited length of stripline transmission line provided with variable lumped capacitors at opposite ends thereof, such capacitors serving to tune the stripline for a fundamental mode of resonance at the operating frequency of the oscillator. The low-impedance bulk-effect device is connected across the stripline at a point near the voltage null of the fundamental resonance. The characteristic impedance and the length of the stripline are adjusted such that the reactance of the line and the reactance of the capacitors at the ends allow the circuit to support full wave resonance at precisely twice the fundamental frequency and therefore develop a second harmonic voltage across the bulk-effect device to improve the conversion efficiency of the oscillator. Power is extracted from the oscillator circuit by means of a filter circuit tuned to pass the fundamental frequency and reject the harmonic. The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department of the Air Force.
TL;DR: Tunable optical continuous wave parametric oscillator using 5145 angstrom Ar laser pump and lithium niobate as nonlinear material, noting large oscillation bandwidth as mentioned in this paper.
Abstract: Tunable optical continuous wave parametric oscillator using 5145 angstrom Ar laser pump and lithium niobate as nonlinear material, noting large oscillation bandwidth
TL;DR: In this paper, an analogue computer model for an avalanche transit-time diode oscillator with single and double-resonant circuit is described Resonant responses of fundamental and subharmonic oscillations are discussed and compared with theory.
Abstract: An analogue-computer model for an avalanche transit-time diode oscillator with single- and double-resonant circuit is described Resonant responses of fundamental and subharmonic oscillations are discussed and compared with theory
Patent•
27 Jun 1969
TL;DR: In this paper, an electronic control device comprising a pair of electrodes connected in an oscillator circuit is described, where electrodes are designed to be held between the hands of a subject and the oscillator output frequency is continuously variable in accordance with the conditions imposed on the electrodes by the subject.
Abstract: An electronic control device comprising a pair of electrodes connected in an oscillator circuit. The electrodes are designed to be held between the hands of a subject and the oscillator output frequency is continuously variable in accordance with the conditions imposed on the electrodes by the subject.
Patent•
10 Jan 1969
TL;DR: In this article, a microwave oscillator including a transistor connected as an oscillator and coupled to a resonator tuned to a first frequency, line means are coupled to the resonator, a step recovery diode is connected in shunt along the line means and a filter arrangement is provided which is tuned to the harmonic of the above-mentioned first frequency and is coupled to line means to derive a signal of the harmonic from the step recovery dode.
Abstract: A microwave oscillator including a transistor connected as an oscillator and coupled to a resonator tuned to a first frequency, line means are coupled to the resonator, a step recovery diode is connected in shunt along the line means and a filter arrangement is provided which is tuned to a harmonic of the above-mentioned first frequency and is coupled to the line means to derive a signal of the harmonic from the step recovery diode.
TL;DR: In this article, a non-degenerate-type self-pumped parametric amplifier using GaAs transferred-electron devices was reported to achieve gains of as much as 30dB, noise figures as low as 18dB, and instantaneous gain-bandwidth products of about 50MHz at Xband signal frequencies.
Abstract: The letter reports experimental results obtained with a non-degenerate-type self-pumped parametric amplifier using GaAs transferred-electron devices. Gains of as much as 30dB, noise figures as low as 18dB, and instantaneous gain-bandwidth products of about 50MHz have been obtained at Xband signal frequencies with the amplifier using GaAs transferred-electron devices oscillating at Q band frequencies.
TL;DR: In this paper, the transition probability of a linearly forced harmonic oscillator system is derived by expanding the evolution operator using an expansion theorem valid for operators obeying the commutation law.
Abstract: The transition probability of a linearly forced harmonic oscillator system is derived by expanding the evolution operator using an expansion theorem valid for operators obeying the commutation law, (A, B) = 1.
01 Nov 1969
TL;DR: In this article, a parametric amplifier with an MIS varactor exhibits gain saturation for high pump voltage, and two MIS varactors connected antiparallel have an even C-V characteristic.
Abstract: A parametric amplifier with an MIS varactor exhibits gain saturation for high pump voltage. Two MIS varactors connected antiparallel have an even C-V characteristic. The differential capacitance varies with twice the pump frequency, and the gain has a flat maximum at a certain pump voltage.
Patent•
29 Aug 1969
TL;DR: An AFC control circuit for an oscillator that is tunable over a wide frequency band produces a relatively constant frequency change or pull-in range at any frequency value within the band.
Abstract: An AFC control circuit for an oscillator that is tunable over a wide frequency band produces a relatively constant frequency change or ''''pull-in'''' range at any frequency value within the band. The control circuit is connected across the main capacitance of the oscillator''s resonant circuit and is comprised of a varactor and a parallel inductance that define a reference resonant frequency lower than any frequency value within the band. The control circuit exhibits an effective capacity at all frequencies of interest and the varactor provides a change in such effective capacity which is related to operating frequency in a manner to achieve the uniform ''''pull-in'''' characteristic.
Patent•
06 May 1969TL;DR: In this article, a linearly polarized difference-frequency wave for which free carriers (electrons or holes) have the effect of subtracting an appreciable amount from the index of refraction determining its propagation constant is generated.
Abstract: A phase-matched tunable millimeter wave or far infrared wave generator or mixer employs semiconductor active media having large bound-electron second-order nonlinear effects but which, in particular instances, are not sufficiently birefringent to be phase-matchable by conventional techniques. There is generated a linearly polarized difference-frequency wave for which free carriers (electrons or holes) have the effect of subtracting an appreciable amount from the index of refraction determining its propagation constant. The linearly polarized wave is generated in crystals of the active medium when the frequencies of a pair of input radiations to be mixed and a tuning condition, such as the magnitude of magnetic field applied transversely to the direction of propagation of the input radiations, are appropriately selected. Also, in a parametric oscillator, one radiation is supplied and a second radiation relatively closely spaced in frequency is highly resonated, the frequency of the second radiation and the difference frequency being variable by variation of the magnetic field magnitude.
TL;DR: In this article, a now typo of driven sub-harmonic oscillator is proposed which depends for its action on the incorporation of a non-linear element with a hysteresis type of currentvoltage characteristic.
Abstract: A now typo of driven sub-harmonic oscillator is proposed which depends for its action on the incorporation of a non-linear element with a hysteresis-type of current-voltage characteristic. Noteworthy features of its performance include its many modes of operation, the availability of power gain, the potentially high division rates and the ability to generate rational fractions of the driving frequency. Two circuits are suggested for generating the required non-linear characteristic.
TL;DR: In this paper, the authors investigated the stability of the resonant periodic motions of a weakly coupled linear and strictly non-linear oscillator subject to weak periodic forcing, where the natural frequencies of the linear oscillator and of the nonlinear oscillators with appropriate energy were assumed to be close to rational multiples of the forcing frequency.
Abstract: This paper is concerned with the investigation of the resonant periodic motions, and their stability, for a weakly coupled linear and strictly non-linear oscillator, subject to weak periodic forcing The non-linear oscillator may be performing either (large) oscillations or rotations The natural frequencies of the linear oscillator and of the non-linear oscillator (with appropriate energy) are assumed to be close to rational multiples of the forcing frequency The equations of motion are transformed into an appropriate standard form, and previously obtained results are applied in order to investigate the resonant periodic motions, and their stability, in the general case The investigation is carried out analytically for a particular example, for which the resonance for the linear oscillator must be fundamental The resonance for the non-linear oscillator may be fundamental, or a subharmonic one in the oscillatory case, and an ultrasubharmonic one in the rotary case