Showing papers on "Injection locking published in 1980"
TL;DR: Stable Fourier-transform-limited single-axial-mode operation of an unstable-resonator Nd:YAG oscillator is achieved and the 10-Hz repetition-rate, 150-mJ, 9-nsec Q-switched Nd-YAG source operated with a measured 50-MHz bandwidth at ±5-MHz frequency jitter.
Abstract: We have achieved stable Fourier-transform-limited single-axial-mode operation of an unstable-resonator Nd:YAG oscillator. The 10-Hz repetition-rate, 150-mJ, 9-nsec Q-switched Nd:YAG source operated with a measured 50-MHz bandwidth at ±5-MHz frequency jitter when injected with a low-power single-frequency pulse from a TEM00-mode Nd:YAG source.
117 citations
TL;DR: In this paper, the authors measured the locking frequency width and locking gain of an AlGaAs double-heterostructure laser with respect to locking frequency and gain, and the relation of the locking bandwidth versus the ratio of locked laser to injected power was consistent with the analysis on injection locking phenomena.
Abstract: Injection locking of an AlGaAs double-heterostructure laser was studied with respect to locking frequency width and locking gain. The relation of the locking bandwidth versus the ratio of locked laser to injected power was consistent with the analysis on injection locking phenomena by Adler. Measured maximum locking bandwidth was 3 GHz, when locking gain was 23 dB. The 40 dB maximum gain was observed with the 500 MHz locking bandwidth. By measuring the beat notes between two temperature-stabilized free running AlGaAs lasers, the linewidth was estimated as 10 MHz.
79 citations
TL;DR: In this paper, a single-mode operation of an AlGaAs double heterostructure semiconductor laser directly modulated at 500 Mbit/s data rate was realized by injection locking.
Abstract: Single-mode operation of an AlGaAs double heterostructure semiconductor laser directly modulated at 500 Mbit/s data rate was realised by injection locking. The power ratio of central injected mode to total spectrum power was 94%.
65 citations
TL;DR: In this paper, an experimental study on optical injection locking of X-band silicon IMPATT oscillators was carried out by modulating a cw GaAlAs laser at subharmonics of the frequency and optically injected into the IMPATT diode, achieving a locking range of several megahertz at frequency ratios ranging from 4:1 to 8:1.
Abstract: An experimental study on optical injection locking of X‐band silicon IMPATT oscillators was carried out. The locking process was achieved by modulating a cw GaAlAs laser at subharmonics of the IMPATT oscillation frequency and optically injected into the IMPATT diode. A locking range of several megahertz can be obtained at frequency ratios ranging from 4:1 to 8:1.
32 citations
Patent•
23 May 1980
TL;DR: In this paper, a GaAs FET structure with a high electric field region, or active region, contacted by source, gate and drain electrodes is provided which can be used for high speed optical detection or for microwave oscillator optical injection locking.
Abstract: A GaAs FET structure with a high electric field region, or active region, contacted by source, gate and drain electrodes is provided which can be used for high speed optical detection or for microwave oscillator optical injection locking. The device provides for efficient coupling of incident optical radiation into the active region, employing confinement and waveguiding regions lying in the plane of the device and adapted to guide incident optical radiation to the active region. GaAs photoconductors are also provided by eliminating the gate electrode.
29 citations
TL;DR: The phase error variance and the correlation between the errors at different oscillators is computed and compared in their behavior for large N and the theory can be easily extended to include these two effects.
Abstract: A set of N identical oscillators (clocks) are connected to form a mutually synchronous network. General matrix expressions are derived for the phase error spectrum at each oscillator when the network operates in the linear regime. For certain topologies of practical interest the phase error variance and the correlation between the errors at different oscillators is computed and compared in their behavior for large N . The results presented assume no thermal noise and no delay between the oscillators. However, the theory can be easily extended to include these two effects.
18 citations
Patent•
02 Jun 1980TL;DR: In this paper, a phase-locked loop circuit for use in locking onto a sub-harmonic of the frequency of a reference source is presented. And the loop can be controlled by a loop control signal generated by the phase detector and loop filter.
Abstract: A phase-locked loop circuit for use in locking onto a sub-harmonic of the frequency of a reference source. An oscillator operating at the sub-harmonic frequency is injection-synchronized to the primary voltage controlled oscillator of the phase-locked loop, thereby causing it to function as a divider. The injection-synchronized oscillator can be controlled by a loop control signal generated by the loop's phase detector and loop filter.
16 citations
16 citations
TL;DR: In this article, a nanosecond and a microsecond pulse duration dye laser was used as the master oscillator, and the experimental conditions then lead to two different injection regimes defined as the CW and the delta pulse regime.
Abstract: Experimental studies of frequency locking by injection are performed using a nanosecond and a microsecond pulse duration dye laser. Either of these two lasers can be used as the master oscillator, and the experimental conditions then lead to two different injection regimes defined as the CW and the delta pulse regime. In both regimes, the locking efficiency, which is measured as a function of the injected flux of the injected wavelength and of the time delay between the two pulses, reaches a value close to unity when the injected flux present in the forced oscillator cavity is at least equal to 10 W · cm-2. An analytical relation is derived to explain the experimental results. The use of the injection locking technique to probe the progressive narrowing of tuned dye lasers and to monitor the occurrence of the laser threshold is emphasized.
13 citations
TL;DR: In this paper, the output power from three Gunn oscillators was combined using a short-slot coupler in conjunction with high-level injection locking with the power combining efficiency of ahout 100 percent at 9.7 GHz.
Abstract: The output power from three Gunn oscillators was combined using a short-slot coupler in conjunction with high-level injection locking with the power combining efficiency of ahout 100 percent at 9.7 GHz. Using the 3-oscillator structure as the building block, we constructed (3/sup 2/ = )9-oscillator corporate structure and (2X4+1=)9- and (2X6+1 = )13-oscillator tandem structures to demonstrate power combining efficiencies of 92, 95, and 93 percent, respectively, at 9.6 GHz.
12 citations
TL;DR: Recent advances in injection mode locking and high-power 10 μm pulse selection have been incorporated into a high- power CO2 laser system built around a single 5 l TEA CO2 gain module.
Abstract: Recent advances in injection mode locking and high-power 10 μm pulse selection have been incorporated into a high-power CO2 laser system built around a single 5 l TEA CO2 gain module. A pulse selected from a line-tuned [to P(20)] injection-mode-locked oscillator was amplified to produce a 20 J, 3 ns pulse with a main-pulse-to-prepulse contrast ratio of >107:1.
Patent•
18 Dec 1980TL;DR: In this article, a combined phase shifter and signal source are formed by injection locking a variable frequency oscillator and the free running frequency control of the oscillator operates as a phase control.
Abstract: A combined phase shifter and signal source are formed by injection locking a variable frequency oscillator. The free running frequency control of the oscillator operates as a phase control when the oscillator is injection locked. The invention functions as a phase shifter which exhibits gain, permitting its use in a unique phased array antenna system.
Patent•
24 Mar 1980
TL;DR: In this article, a GaAs FET structure with a high electric field region, or active region, contacted by source, gate and drain electrodes is provided which can be used for high speed optical detection or for microwave oscillator optical injection locking.
Abstract: A GaAs FET structure with a high electric field region, or active region, contacted by source, gate and drain electrodes is provided which can be used for high speed optical detection or for microwave oscillator optical injection locking. The device provides for efficient coupling of optical radiation into the active region through an opening in a semi-insulating substrate used to support the device. A buffer layer between the active region and the substrate prevents leakage current to the substrate, permits a larger illumination window for improved optical coupling and provides mechanical support for the FET detector. GaAs photodetectors are also provided by eliminating the gate electrode.
Patent•
02 May 1980
TL;DR: In a swept frequency oscillator arrangement compensation is provided for the nonlinearities in the tuning sensitivity of the oscillator as mentioned in this paper, where the non-linearities are initially measured and stored.
Abstract: In a swept frequency oscillator arrangement compensation is provided for the non-linearities in the tuning sensitivity of the oscillator. The non-linearities are initially measured and stored. Subsequently the stored values are used to control the rate at which the clock pulses are integrated to produce a control signal for the oscillator.
TL;DR: In this paper, the authors investigated injection locking as a means for control of optical pulse duration and polarization in a XeF laser, and showed that injection of a low-level 1 ns optical pulse into a XEF oscillator can improve the performance of the ultraviolet laser.
Abstract: Injection locking is investigated as a means for control of optical pulse duration and polarization in a XeF laser. Intense short‐pulse generation in the ultraviolet is achieved by injection of a low‐level 1‐ns optical pulse into a XeF oscillator. Control of laser output polarization by injection locking is demonstrated and studied as a function of injected signal level. Enhancement of XeF electric‐discharge laser efficiency by injection pulse ’’priming’’ is observed.
TL;DR: In this paper, the possibility of obtaining phase locking by injection of the reference signal into the laser is investigated, and from the results obtained, it is inferred that this technique can be efficiently used in the frequency range up to 1 THz.
Abstract: Phase locking of optically pumped far-infrared lasers to highly stable synthesized signals is an interesting goal, at least for metrological purposes. In this paper, the possibility of obtaining such a stabilization by injection of the reference signal into the laser is investigated, and from the results obtained, it is inferred that this technique can be efficiently used in the frequency range up to 1 THz.
TL;DR: In this article, a model of a specific Josephson microwave circuit, that of a Josephson oscillator, was used to predict the RF behavior of a real JO oscillator from a knowledge of the experimentally measured microwave circuit parameters, such as critical current, and junction shunt resistance.
Abstract: In this paper, we deal with a model of a specific Josephson microwave circuit, that of a Josephson oscillator, and show that the RF behavior of a real Josephson oscillator may be predicted from a knowledge of the experimentally measured microwave circuit parameters, the junction critical current, and junction shunt resistance. Based on observations made with an electronic analog, we present an approximate analytical method for calculating the junction impedance or, rigorously speaking, the appropriate single sinusoidal-input describing function. Emphasis is placed on the proper use of the impedance, for example, in calculating the operating point and the expected output power of the oscillator. The circuit model used is that of a junction, described by the resistively shunted junction model, coupled to a series LCR resonance. Further confirmation of the validity of the circuit-theory approach is obtained by using the injection-locked oscillator theory of Kurokawa to predict the in-lock amplitude variation of a Josephson oscillator exposed to a weak synchronizing signal. Experimental data describing the amplitude variation and output power of an oscillator consisting of a point-contact junction placed in a 9.72-GHz coaxial resonator are presented. The data demonstrate the reasonable agreement obtained when the measured critical current and shunt resistance are used with the analytical expression for the junction impedance and the circuit theory to predict the RF behavior of a Josephson oscillator. Circuits more complex than our specific example may be handled by means of describing function techniques recently developed in the area of nonlinear solid-state microwave devices.
TL;DR: In this article, a technique of improving the locking time of an injection synchronized oscillator (ISO) has been suggested, and a method of evaluating the locking range and locking times of an ISO in the presence of an interfering tone is presented.
Abstract: This correspondence begins with a critical review of the phenomenon of injection synchronization in an oscillator incorporating a low- Q tank circuit. A technique of improving the locking time of an injection synchronized oscillator (ISO) has been suggested. Also presented is a method of evaluating the locking range and locking time of an ISO in the presence of an interfering tone. The response of an ISO to an FM signal has been studied. Experimental results corroborating the theoretical findings have been given.
TL;DR: Simultaneous longitudinal and transverse mode-locking was evidenced by periodic focusing of the internal short pulse in TEA-CO(2) laser cavities made of two copper mirrors.
Abstract: Single short pulses were injected in TEA-CO(2) laser cavities made of two copper mirrors. Simultaneous longitudinal and transverse mode-locking was evidenced by periodic focusing of the internal short pulse. The focusing action could be eliminated by short train injection.
TL;DR: In this article, the feasibility of phase locking a FIR laser by injection of a highly stable synthesized signal is examined and the theory of injection locking is revised in order to take into account the characteristic features of FIR lasers and turns out to be in satisfactory agreement with the experimental data reported.
Abstract: In this paper the feasibility of phase locking a FIR laser by injection of a highly stable synthesized signal is examined. The theory of injection locking is revised in order to take into account the characteristic features of FIR lasers and turns out to be in satisfactory agreement with the experimental data reported. From the results obtained, it is inferred that the state of the art of submillimetric multipliers makes it possible to stabilize FIR laser emissions up to about 1 THz.
TL;DR: In this article, the laser oscillator and parametric oscillator were analyzed in the presence of an externally injected signal and an exact expression for the stationary probability distribution was obtained for Δi = 0.
Abstract: The laser oscillator and parametric oscillator are analyzed in the presence of an externally injected signal. Synchronization to the external signal is possible only if it is larger than a certain magnitude. In the weak synchronization limit, expressions for the oscillator frequency and linewidth as a function of detuning (Δi) are obtained. An exact expression for the stationary probability distribution is obtained for Δi=0. It is shown that laser noise due to reflected signal may result from the repetitions of the ’’locked’’ and ’’unlocked’’ state arising from temperature variation within the laser itself.
TL;DR: In this paper, the effects of a second harmonic resonance circuit on IMPATT oscillator characteristics have been investigated, and it is found that the negative conductance at the fundamental frequency is increased by properly selecting the load admittance at the second harmonic frequency.
Abstract: The effects of a second harmonic resonance circuit on IMPATT oscillator characteristics have been investigated. The admittance of an IMPATT diode is measured using an injection locking method simultaneously at the fundamental and second harmonic frequencies. A computer analysis, approximating the p+nn+ IMPATT structure with a Read diode, is carried out and the results are compared with the experiment. The theory agrees well with the experiment and has revealed characteristics of IMPATT diodes in the presence of an ac voltage component at second harmonic frequency. It is found that the negative conductance at the fundamental frequency is increased by properly selecting the load admittance at the second harmonic frequency. Characteristics of an IMPATT oscillator with a second harmonic resonance circuit at microwave and millimeter wave frequencies then are examined based on the computer simulation. The output power at the fundamental frequency varies over 10 dB when the second harmonic circuit conditions are varied near the resonance condition. The output power at fundamental frequency can be made a few decibels higher for optimized admittance at the second harmonic circuit than under off-resonance conditions. Considerable output power at the second harmonic frequency is obtained under the above resonance conditions, and is described in detail.
01 Dec 1980
TL;DR: In this article, the performance of a 1 micro set XeF laser pulse and Raman converter scaling have been investigated, showing that injection signal power to output laser power on the order of.00001 is adequate for efficient injection-locking to occur.
Abstract: : Injection locking performance of a 1 micro set XeF laser pulse and Raman converter scaling have been investigated. Narrowband ultraviolet radiation from a frequency-doubled dye laser has been used to control the linewidth and polarization of a long pulse-length electron beam-excited XeF laser. Linewidths of 0.004 nm have been achieved in the 353 nm band of the XeF (B yields X) Laser transition. Over 90% of the energy in the free-running laser pulse has been extracted in the narrowband injection-locked pulse. Ratios of injection signal power to output laser power on the order of .00001 are adequate for efficient injection-locking to occur. Efficient Raman conversion of microsecond-pulse, injection-locked XeF (353 nm) laser radiation into the blue-green region via the second Stokes shift in hydrogen has been demonstrated using a Raman oscillator- amplifier scheme. Strong depletion of the pump and the first Stokes radiation accompanied by a dominant second Stokes (500 nm) output was observed for the first time. Amplifier power conversion efficiency of 43% was achieved along with a blue-green output energy of 1.7 J at an energy efficiency of 34%. These data support Raman converter scaling analyses which predict feasibility of efficient XeF-to-blue-green conversion at higher energies.
01 Jan 1980
TL;DR: In this paper, a bank of SAW oscillators has been fabricated and locked to a comb generator, and the injection locking bandwidth is calculated from phase slope and the ratio of injected voltage and oscillator signal levels.
Abstract: SAW oscillators are finding increased application in direct frequency synthesizers due to their excellent phase noise and good temperature stabil ity. In such applications it is often desirable to injection lock a bank of SAW oscillators to a single reference to establish coherence and improve stability. The injection locking properties of SAW oscillators have therefore been investigated. It has been found that with minor modification, the classic theory of injection locked oscillators can be applied to SAW oscillators. As the theory p redicts, phase slope is the delay line parameter which establishes the injection locking p roperties of SAW oscillators. I njection locking bandwidth can be calculated from phase slope and the ratio of injected voltage and oscillator signal levels. Data is presented showing the excellent fit of theoretical and measured injection locking bandwidth for SAWs of various delay times. standing of injection locking, a bank of SAW oscillators has been fabricated and locked to a comb generator. Data for this circuit is also presented. Based on this under