Abstract: Two or more signal interaction structures (16,18), which may be klystron or traveling wave structures (32,50), are axially disposed in series between an electron gun (12) and a collector (14) for selectively velocity modulating an electron beam (20) generated by the gun (12) with a microwave input signal (IN1,IN2) and extracting a resulting amplified microwave output signal (OUT1,OUT2) from the beam (20). The interaction structures (16,18) are designed to operate in different frequency bands, for example the X and Ku bands, with only one of the structures (16,18) having an input signal (IN1,IN2) applied thereto at any given time. The interaction structures (16,18) are further designed such that the structures (16,18) which are not being used do not affect the structure (16,18) which is being used.

Abstract: A klystron amplifier in which the drift tube is in the form of a casing and a central member disposed coaxially about the same centerline to form a coaxial space between the central member and the casing which runs parallel to the centerline, and through which the klystron's electron beam flows. The casing and central member are maintained at ground potential, which maintains the space charge of the electron beam at a low level, permitting the klystron to operate more efficiently and output higher power.

Abstract: A klystron device comprises an array of cold-cathode field emission elements arranged to form a distributed amplifier which further comprises a modulation strip line and a catcher strip line. A collector electrode is spaced from the catcher strip line. The device may include a deflector for returning electrons emitted by the elements back to the modulation strip line so that the device acts as an oscillator.

Abstract: The invention relates to a low-noise amplification device of an optical wave. Signal wave (F.sub.s) to be amplified interferes with a pump wave (F.sub.p) in such a nonlinear medium (1) as a photorefractive crystal. To reduce the noise considerably, even to eliminate it, the establishing of noise-generating interferences therefore is prevented by moving, by rotation around an axis O, the nonlinear medium.

Abstract: A band selector for a klystron includes a cam carrier and a plurality of cam followers. The cam carrier includes a plurality of cams with the cams being arranged in a plurality of rows. Each of the cam followers has a first end adapted to be mounted to a respective one of the plungers in the klystron and a second end. The cam carrier is positionable so that a selected one of the rows aligns with the cam followers. The cam followers are normally biased so that the second end of the cam followers abuts a respective one of the cams. The band selector further includes a first member movable between a first position and a second position. When the first member is in the first position, it is non-interactive with the cam followers. When the first member is moved to its second position, it becomes engageable with the first end of each of the cam followers to remove the second end of the cam followers from abutment with the respective one of the cams.

Abstract: There is provided a high performance extended interaction output circuit [EIOC] having two cavities. The EIOC of the present invention has an image impedance which is twice the magnitude of its output load resistance. The EIOC of the present invention also includes a three cavity EIOC which has two image impedances, the second image impedance being one half the magnitude of the first image impedance while the output load impedance of the three cavity EIOC is one third the magnitude of the first image impedance.

Abstract: A klystron comprises a plurality of resonant cavities, the frequency of which is defined by a piston within each cavity. In order to change the frequency of the klystron, each piston is provided with a rod applied against an adjusting screw under the pressure of a spring. In order to reduce the bulk of the springs, the distance between a screw head and the plate on which the springs are applied remains constant irrespective of the length of the adjusting screws. This is obtained by means of a set of switches which are fixed on the movable plate and control the compression of the springs by checking the position of a cup in which each spring exerts its force on the corresponding piston rod.

Abstract: The source and the device comprise a generator of a pump wave, optical means for coupling with a monomode optical fiber for guiding and highly confining the pump wave so that a four photon non linear interaction is created. At least one section of this optical fiber is disposed in a thermostat controlled enclosure associated with a temperature control device so as to obtain continuous tuning in a range of frequencies belonging to the near infra red spectrum.

Abstract: An amplifying arrangement includes a klystron in which an electron beam interacts with a high frequency signal to produce a modulated amplified signal. The high frequency signal is maintained at a substantially constant amplitude and modulation of the amplified signal is provided by controlling the electron beam current.

Abstract: Klystrons are inherently non-linear and have an amplification characteristic which is frequency dependent on both signal amplitude and beam current. This may be compensated for by applying suitable correcting signals to a beam controlling electrode of the klystron thereby changing its electron beam current over the whole excursion of a modulating signal. A klystron arrangement in accordance with the invention is particularly suitable for use in a television transmitter, enabling full time modulation to be carried out with a significant improvement in the operating efficiency of the klystron.

Abstract: A processor-controlled drive motor system for tuning a cavity klystron monitors the output (amplitude-vs-frequency) of the klystron and compares that monitored performance output with an intended amplitude-vs-frequency profile. Differences between the two characteristics are employed by the processor to generate a set of tuning cavity control signals through which respective stepping motors for displacing each cavity tuning slug are driven. The processor iteratively adjusts the cavity tuner control signals in accordance with a prescribed kylstron tuning program until the monitored amplitude response is within a prescribed tolerance of a preestablished characteristic stored in memory.

Abstract: A new optical parametric oscillator which employs a urea crystal is disclosed. The organic crystal makes the oscillator broadly tunable, so that the entire spectral range from the ultraviolet to the near infrared is accessible.The urea optical parametric oscillator is angle tunable, and has a high efficiency.

Abstract: A parametric electric machine consists of a series resonant circuit, which has a capacitance (C) which is adapted to be mechanically varied, an inductance (L) and a resistance (R). The no-load values of the capacitance (C.sub.o), inductance (L.sub.o) and resistance (R.sub.o) fulfill the threshold condition ##EQU1## and at least one of the parameters L, R and C of the resonant circuit is a function of the current flowing in the resonant circuit.

Abstract: Mono-pulses of light are generated by time compression of laser energy. A Raman medium is located in a low Q energy storage cavity having low losses for light at a predetermined frequency and energy delivered by a laser is that frequency in the storage cavity. The Raman medium is also located in a Stokes cavity dimensioned for having a high gain at a Stokes frequency. Most of the stored energy at the Stokes frequency is extracted by a single to and fro travel through the Stokes cavity.

Abstract: A cyclotron resonance maser system includes coaxial coupling between coaxial wave guides. Such coupling is provided between an outer coaxial waveguide through which a gyrotron electron beam passes in generating or amplifying microwaves and an inner coaxial waveguide terminating in an annular window. The coupling separates the microwaves from the electron beam before the collector region of the gyrotron so that the collector dimensions are not related to, and hence restricted by, the wavelength of the output microwaves. The particular preferred coupling includes substantially axial slots in the common wall between the respective waveguides which slots provide selective coupling between the waveguides in the desired modes and limiting mode conversion. The coupling is preferably between a TE.sub.On or TE.sub.ml mode in the outer input waveguide and a TE.sub.On' mode in the inner, output waveguide, n and n' being integers greater than 1. A preferred resonant cavity limits the generated microwaves to a TE.sub.

Abstract: A klystron is provided for supplying power with optimum efficiency across a variable impedance load. To attain this result, the field in the output cavity of a klystron is detected by a probe. This field supplies the image of the voltage at the terminals of the interaction gap. The signal supplied by the probe is used for adjusting the amplitude of the ultra-high frequency voltage applied to the input cavity so that the voltage of the terminals of the interaction gap remains less than the tolerable maximum whatever the ratio of standing waves reflected back by the output device.

Abstract: The means providing capacitive decoupling between the inside cylinder and a grid electrode are disposed at about one fourth of the wavelength of the highest operating frequency from the tube end of the inside cylinder. This is a current node, and dielectric losses at the highest frequency are thus greatly reduced. The match is less good at lower frequencies, but the corresponding dielectric losses are much less at lower frequencies. The first piston provides capacitive coupling between the first and second cavities whereby the entire outside cylinder may be maintained at ground potential.

Abstract: A cylinder or barrel fitted with cams is used to limit the outward movement of spring-loaded plungers attached to cavity shorting bars in a klystron. Different tunings of the klystron are achieved by rotating the cylinder so that different rows of cams limit the plungers. A linear solenoid is used to decouple the plungers from the cams before rotation. A stepping solenoid is used to move the cylinder from one setting to another.

Abstract: A klystron tuning control system has a D.C. motor which is connected to the tuning shaft of the klystron. The position of the tuning shaft is detected electrically and used to control the turning of the D.C. motor in order to reduce to zero a difference between the output voltage of the detecting means and a reference voltage. At zero, a coincidence signal is produced so that a counter means may count a predetermined number and provide an output responsive to which the D.C. motor is operated in only a predetermined direction for a short period of time.

Abstract: A power amplifier including a klystron is stabilized against variations in output power with a simplified servo-loop system and cooperating temperature compensation. The system is fully solid-state, digital, and includes an operator-presettable initial power selector, a power output sensor, comparator logic, variable attenuation responsive to error signals indicative of deviation from the preset power, and temperature compensation means, for assured accuracy and stability.

Abstract: A surface-acoustic-wave device wherein a plurality of metal strips (S) are provided on a propagation path of surface acoustic wave which is formed in a laminate comprised of a piezoelectric layer (23) and a semiconductor (1), the metal strips are extended onto the semiconductor outside the propagation path of surface acoustic wave, and depletion layer capacitance non-linearity created on the semiconductor surface at a region where the metal strips are extended is used as a main factor of a parametric interaction.

Abstract: The present invention relates to a subharmonically pumped hysteretic superconductor-insulator-superconductor (SIS) junction mixer. The hysteretic junction (10), achieved by not suppressing the critical current I.sub.c of the junction, is responsive to a first source of a pump signal (12) at a frequency .omega..sub.p and a second source of an input signal (14) at a frequency .omega..sub.i, to produce a non-zero output signal at a frequency .omega..sub.o =.vertline..omega..sub.i -2.omega..sub.p .vertline., during either an overpumped or underpumped condition. The hysteretic nature of the junction allows the mixer to operate in a switching mode, thereby producing low-noise mixing with gain.

Abstract: A frequency-conversion apparatus including, among others, a single active component in common use for signal amplification and local oscillation with its operating point selected in its linear region, but not in its saturation region. With this device, there is no need for any special components conventionally used in this type of apparatus, such as a nonlinear circuit for controlling oscillation output and an extraction circuit for feeding the local-oscillation signal to the frequency mixer as conventionally arranged outside of the oscillation loop.

Abstract: A backward-wave Raman amplifier or pulse compressor for compressing laser pulses. A laser pulse, or pump beam, of relatively long duration enters one end of the compressor. A short, initiating Stokes-Raman pulse enters the other end of the compressor and absorbs energy from the pump beam as the Stokes-Raman pulse traverses the compressor. The cross-sectional area of the Stokes-Raman pulse within the compressor increases linearly with distance traversed through the compressor so that the energy density within the pulse remains substantially constant as the pulse traverses the compressor and receives energy from the pump beam which traverses the compressor in the opposite direction. The cross section of the pump beam also varies linearly with distance within the compressor so as to coincide substantially with the cross section of the Stokes-Raman pulse and thus achieve efficient compression.

Abstract: A frequency selector apparatus which effects a frequency selection by providing at least one reflecting electrode at a position adjacent elastic surface wave transducer or transducers provided in an acoustic wave propagation track in a piezoelectric medium so as to reflect a frequency component selected by a parametric interaction with an a.c. electrical signal applied to said reflecting electrode.

Abstract: A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

Abstract: A device for producing stimulated Raman scattering of CO.sub.2 laser radiation by rotational states in a diatomic molecular gas utilizing a Stokes injection signal. The system utilizes a cryogenically cooled waveguide for extending focal interaction length. The waveguide, in conjunction with the Stokes injection signal, reduces required power density of the CO.sub.2 radiation below the breakdown threshold for the diatomic molecular gas. A Fresnel rhomb is employed to circularly polarize the Stokes injection signal and CO.sub.2 laser radiation in opposite circular directions. The device can be employed either as a regenerative oscillator utilizing optical cavity mirrors or as a single pass amplifier. Additionally, a plurality of Raman gain cells can be staged to increase output power magnitude. Also, in the regenerative oscillator embodiment, the Raman gain cell cavity length and CO.sub.2 cavity length can be matched to provide synchronism between mode locked CO.sub.

Abstract: A multi-cavity klystron device having a plurality of resonance cavities, comprising a plurality of movable elements, each of which is mounted on each of said resonance cavities and which is adapted to change the resonance frequency in each cavity, a plurality of tuning means for giving a reciprocal movement to each movable element against a resilient member provided therefor, a plurality of pulse motors coupled to the tuning means, and a preset means for controlling pulse supply to each pulse motor, wherein a predetermined number of pulses stored in the memory units of the preset means are selectively applied to the pulse motors to rotate each pulse motor in correspondence with the number of pulses, thereby changing each resonance frequency of each cavity.

Abstract: A new mode of operation of an optical cavity is disclosed. In this "regenerative pulsation" mode, a substantially nonvarying input yields an output consisting of a train of pulses. Fractional modulations exceeding 90 percent are demonstrated.

Abstract: A single varactor diode parametric amplifier is described which has a broadband termination at the upper sideband frequency in the pump waveguide. This termination presents an open circuit condition at the upper sideband frequency, which, in combination with an upper sideband fequency choke on the input signal circuit transmission line achieves low noise, high gain characteristics with minimum interaction with the input signal, pump, and idler circuitry. Theoretical noise figures can be obtained at low power consumption, high gain, and broadband performance.

Abstract: A tunable far infrared generator makes use of a four-photon mixing process that cycles among highly excited atomic states, the lowest of which states is reached from the atomic ground state by a visible or ultraviolet photon, and the remainder of which states are connected by transitions in the infrared.

Abstract: Amplifier device for the UHF-TV band, assembled from cylindrical conductors which are coaxially arranged with respect to one another and connected to a tetrode. The screen grid is grounded and the control grid is provided with dc voltage connecting terminals required for setting the tetrode.

Abstract: This invention provides a klystron amplifier arrangement having means for producing a radial component of magnetic field tending to direct beam electrons out of their path from the electron gun to the collector electrode of the kylstron. By suitably choosing the strength of the radial component of magnetic field generated undesired slow electrons in the beam will tend to be deflected, while the relatively fast electrons will be substantially unaffected.The radial component of magnetic field may be axially asymmetrical or symmetrical and may be generated in a variety of ways, for example, by means of magnetic material introduced into the field region of the normally provided main solenoid or by the use of an auxiliary winding. The magnetic material may form at least part of a cylinder or cylinders surrounding the beam path, for example, if provided as at least part of a drift tube or a water jacket. Any auxiliary solenoid may for example, be wound around a cooling jacket surrounding the beam path.

Abstract: A device is disclosed which is capable of amplifying optical signals. The absorptive and dispersive properties of a cavity-enclosed nonlinear medium are combined with the transmission properties of the cavity to yield an input-output characteristic curve that displays gain or bistability.

Abstract: Schemes for generating tunable coherent radiation by noncollinear phase-matched sum-difference frequency optical mixing in a nonlinear medium for use, by way of illustration, in connection with uranium 235-isotope separation in UF.sub.6.

Abstract: A method and apparatus for phase-matching the output of a four-wave nonlinear optical mixing process is disclosed. The method produces phase-matching that is independent of variations in density of the conversion medium and extends over the entire frequency spectrum from the far infrared to the vacuum ultraviolet. The phase-matching is accomplished by adjustment of the frequencies of three input lasers so that the desired frequency is produced, the condition for two-photon resonance enhancement is met, and the phase-matching condition is satisfied.

Abstract: A balanced circuit for IMPATT amplifiers and oscillators, which includes at least one pair of anti-series connected matched avalanche diodes electrically connected to the junction of a balanced and an unbalanced transmission line is disclosed. The diodes which are pumped by a large-signal input, are d-c biased to operate in the avalanche condition. A parametrically generated pair of unwanted idler frequencies are separated so that one component of the parametric-pair flows in the balanced line, and the other component flows in the unbalanced line. A central branch of the unbalanced line portion is resistively loaded to overcome the parametrically induced negative resistance of the diodes operating in the avalanche condition, and to suppress all incipient unwanted parametrically generated frequencies. The resistance loading, which is frequency independent, has little effect on the impedance presented to the diodes at the large-signal frequency.

Abstract: Amplification of optical signals propagating through a first waveguide is achieved by modulation of high intensity light propagating through an elastomeric waveguide responsive to said signals, the modulation of the high intensity light being accomplished by an apparatus including a photodiode for registering the modulation of the optical signals and an electrode arrangement for causing corresponding light-modulating deformation of the elastomeric waveguide, the circuitry between photodiode and the electrode arrangement including a resistor and a D.C. power source.

Abstract: A parametrically-stable microwave circuit comprises in cascade a negative resistance diode, a stabilizing network, and a complementary type filter. The complementary type filter presents a substantially constant impedance to the stabilizing network from low frequencies to the operating frequency by selectively coupling the diode microwave signals to a dummy load or to a circuit load. With its termination thus controlled, the stabilizing network may be designed to suppress spurious parametric oscillations by presenting to the negative resistance diode a predetermined impedance over a broad range of frequencies.

Abstract: A device is disclosed which is capable of amplifying optical signals. The absorptive and dispersive properties of a cavity-enclosed nonlinear medium are combined with the transmission properties of the cavity to yield an input-output characteristic curve that displays gain or bistability.

Abstract: The disclosure relates to a laser apparatus for generating a line-tunable pulsed infrared difference frequency output. The apparatus comprises a CO.sub.2 laser which produces a first frequency, a CO laser which produces a second frequency and a mixer for combining the output of the CO.sub.2 and CO lasers so as to produce a final output comprising a difference frequency from the first and second frequency outputs.

Abstract: A parametric amplifier which includes series coupled diodes contained in a resonating wave guide for providing a low noise figure by limiting the impedance to the idler circuit and inhibiting current flow in the upper sideband circuit. The mechanism for inhibiting current flow of the upper sideband circuit is independent of the characteristic impedance of the resonating wave guide to provide a constant, low power requirement, with high gain and broadband performance.

Abstract: A lightweight, tunable, wideband output circuit for a klystron amplifier loys a first cavity resonator which is excited by the modulated electron beam and a filter cavity resonator coupled thereto which is provided with a coaxial probe that both capacitatively tunes this resonator and serves as a means for extracting the output signal therefrom in a mode-free manner.

Abstract: The low noise parametric amplifier disclosed is a non-cryogenic non-redundant plural stage unit with excess gain such that failure of any one stage results in only minor degradation of signal-to-noise ratio. While the amplifier is of general application, it is specifically intended for use in the receiver of an unattended earth terminal of a satellite communication system. In this environment, reliability is achieved by employing a plurality of cascaded, modular parametric amplifier stages. Each stage includes a varactor diode, a pump circuit with its oscillator, a bias circuit, and temperature stabilizing circuitry employing a Peltier junction. The stages are connected to a multi-port circulator by quick disconnect couplings which permit the modular amplifier stages to be removed and replaced without any interruption in the operation of the amplifier.

Abstract: A reliable earth terminal for satellite communications systems capable of unattended operation for extended periods of time is disclosed. The terminal includes an antenna with a single fixed reflector which can provide multiple beams, each of which can be positioned by small feed motion. The transmitter is of a modular construction, using a relatively low power traveling wave tube power amplifier for each increment in the operating band. The transmitting chains are designed to carry voice, data, or television signals to a satellite and include a modulator, IF amplifier, band-limiting filter, frequency converter, and power amplifier. Each amplifier is capable of operating over the full operating band; however, operation of each amplifier is limited to an assigned increment through the use of band-limiting filters. A single, redundant high power amplifier is provided and may be remotely switched into any one of the transmitting chains in the event of a failure.