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Quantum Electronics, IEEE Journal of

Issue 9 • Date September 1984

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Displaying Results 1 - 21 of 21
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • Second workshop on laser acceleration of particles

    Page(s): 994
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    Freely Available from IEEE
  • Announcing a special issue of the IEEE journal opf quantum electronics on optical bistability

    Page(s): 995
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    Freely Available from IEEE
  • An analytic model for the modulation response of buried heterostructure lasers

    Page(s): 1008 - 1015
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    This paper describes an analytic model for the modulation response of buried heterostructure (BH) semiconductor lasers. Using a space-averaged carrier density approach, explicit expressions that take into account the combined effects of carrier diffusion and spontaneous emission are derived for the transient decay time of the relaxation oscillations, and the small-signal modulation response for the carriers and photons. The dynamic shift of the lasing wavelength is estimated by calculating the fluctuations of the carrier density during small-signal modulation. Using the analytic solutions obtained, a network synthesis approach is used to derive two-port circuit models for the device. The validity of the theoretical model is verified by comparing the modulation characteristics of a BH laser measured experimentally to that simulated by circuit analysis. View full abstract»

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  • An analysis of gain-switched semiconductor lasers generating pulse-code-modulated light with a high bit rate

    Page(s): 1016 - 1022
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    A theoretical analysis of gain-switched semiconductor lasers is described. Results of the numerical solution of the coupled rate equations for photon and electron densities are presented, along with analytical expressions which have been derived by using certain approximations to solve these nonlinear differential equations. The two sets of results are seen to be in good agreement. The design requirements to be met in order to use the pulse-code-modulated output in an optical communications system are discussed. It is shown theoretically that bit rates, of the order of 7 Gbits/s without time-division multiplexing, and 35 Gbits/s with multiplexing can be obtained. View full abstract»

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  • Dynamics of the optically pumped midinfrared NH3laser at high pump power - Part I: Inversion gain

    Page(s): 1051 - 1060
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    A simple rate-equation model is shown to account for all the major features of gain dynamics in pulsed NH3lasers operating with buffer gases. The model is validated by a detailed comparison to measured gain coefficients for two different pumping transitions, and accurately predicts gain distributions as a function of rotational quantum number. The two major concepts embodied in the model are the assumption of rapid thermalization of the rotational populations and the absence of vibrational energy transfer between ortho-NH3and para-NH3. The parameters which determine the effectiveness of buffer gases are also identified. N2and Ar are particularly effective buffer gases and He is much less effective. View full abstract»

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  • Dynamics of the optically pumped midinfrared NH3laser at high pump power - Part II: Raman gain and ac stark shifts

    Page(s): 1060 - 1064
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    Coherent effects produced by high-intensity pumping onaR(6, 0) in NH3are investigated for both the pure gas and for mixtures with an inert buffer gas. Two different Raman transitions are observed. One is the usual directly pumped Raman transition, and the other is pumped indirectly since it first requires a large population transfer to the upper vibrational level. This population transfer also creates inversion gain, shifted away from line center due to ac Stark shifts, on both transitions. Raman gain coefficients of 10 percent ċ cm-1and inversion gain coefficients > 2 percent ċ cm-1are observed, and compared to a combined density-matrix and rate-equation model. View full abstract»

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  • The high-power iodine laser

    Page(s): 1098
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    First Page of the Article
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  • [Back cover]

    Page(s): 0
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  • Continuously tunable sum-frequency generation involving sodium Rydberg states

    Page(s): 1074 - 1078
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    Broadly tunable sum-frequency generation has been observed in a vapor of atomic sodium in the presence of a dc electric field. This field induces achi^{(2)}nonlinearity which is resonantly enhanced when the sum frequency corresponds to the energy separation between the ground state and an atomic Rydberg state. In a vapor of number density4 times 10^{14}cm-3, we obtain an energy conversion efficiency as large as3 times 10^{-4}and achi^{(2)}as large as1.2 times 10^{-8}ESU. We have also observed sum-frequency generation in the absence of an applied dc field, and we relate these observations to mechanisms that have been proposed to explain this effect. View full abstract»

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  • On fluctuations and transients in injection lasers

    Page(s): 1032 - 1044
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    A new computer model of the semiconductor injection laser is described. The electron-photon interactions are introduced using a Monte Carlo technique in combination with multimode rate equations to compute laser output versus time and to compute output power probability density. Laser turn-on initially in a side mode, followed by evolution to the normal equilibrium modal power distribution, is shown to be intrinsic and a natural consequence of fluctuations in the modal powers at the moment the laser passes through threshold. Calculations of fluctuations in the equilibrium power levels show that occasional dropouts of the main-mode power are also a natural consequence of electron-photon interactions. Reduction in equilibrium fluctuations and in turn-on fluctuations can be achieved by increasing the laser power-output level, by increasing the mirror reflectivities, and by decreasing the laser length. This work indicates that conventional injection lasers must be operated at or above the 1 mW level in order to assure an error rate of 10-9in digital systems. The well-known transition from thermal-noise statistics below threshold to Poisson statistics well above threshold is still evolving in the 0.5-2 mW region in the injection laser. View full abstract»

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  • Theoretical analysis of combustion-driven 16µm CO2gas dynamic lasers

    Page(s): 1086 - 1092
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    A numerical analysis is presented with a combustion-driven 16 μm CO2gas dynamic laser operating on liquid fuel and liquid oxidizer constituted of benzene (C6H6) and nitrous oxide (N2O), respectively. Adopting a sharp-edged nozzle with an area ratio of 100, optimization of equivalence ratio φ, reservoir pressure P0, and nozzle throat heighth*was performed by considering conditions of no steam condensation and exhausting the combustion gas to the atmosphere. The analysis showed that the maximum value ofG_{16} = 0.48m-1for small-signal gain andE_{16}^{max} = 9mJ/(l . atm . pulse) for available specific energy would be attainable with theP(15)line of the (0200)-(0110) transition. View full abstract»

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  • Two-dimensional propagating beam analysis of an electrooptic waveguide modulator

    Page(s): 1093 - 1097
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    Diffused waveguides are analyzed employing the propagating beam method. By reducing the problem to two dimensions by the effective index method, a reduction of the computer time by a factor of 100 is achieved. The method has been exemplified by aY- branch electrooptic waveguide modulator. The calculated output power versus applied voltage is in good agreement with results found in the literature. We expect the method to be a powerful tool when optimizing the geometry of modulators and similar waveguiding circuits with respect to physical dimensions and losses. View full abstract»

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  • Repetitively pulsed transversely excited Sr+recombination laser

    Page(s): 1006 - 1007
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    Operation of a transversely excited strontium-ion recombination laser at repetition rates up to 500 Hz is reported. Maximum average output power of 90 mW on the 430.5 nm transition has been obtained from a sealed-off device of active volume ∼ 40 cm3at a pulse repetition frequency of 200 Hz. This performace was achieved in the absence of any discharge preionization or forced recirculation of the gas mixture. View full abstract»

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  • Slab waveguides characterized by moments of the index profile

    Page(s): 996 - 999
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    The fundamental mode of a symmetric slab waveguide is described to a high degree of accuracy using only two moments of the refractive index profile rather than its exact form. The two moments can be used to define an equivalent step index slab waveguide, and the fundamental mode propagation constant of an arbitrary profile guide is given by the step index value multiplied by a simple correction factor. The limit to single-mode operation, the second-mode cutoff point, is also given by a simple formula requiring only profile moments. Numerical confirmation of the method is given. View full abstract»

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  • High frequency heterodyne spectroscopy with current-modulated diode lasers

    Page(s): 1045 - 1050
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    The use of current-modulated semiconductor lasers for optical heterodyne spectroscopy has been investigated at modulation frequencies up to 2.6 GHz. The current modulation produces a simultaneous frequency and amplitude modulation of the laser output. A characteristic heterodyne spectrum occurs when the modulated laser probes a narrow absorption line. In order to analyze the measured spectra, a complete line shape theory has been derived for heterodyne spectroscopy with frequency- and amplitude-modulated laser light. The results show how the obtained signals depend on the modulation frequency and the phase difference between the frequency and the amplitude modulation. The measurement technique permits investigation of the FM-AM phase difference of current-modulated semiconductor lasers. View full abstract»

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  • Operation mechanism of electrooptic multimode X-switches

    Page(s): 999 - 1002
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    The operation mechanism of electrooptic multimode switches using crossing channel waveguides (X-switch) is investigated theoretically and experimentally. The light propagation through the X-structure as well as the switching behavior of the device is explained in terms of local normal modes. The theoretical model is confirmed by numerical calculations (BPM) and by experiments using Ti:LiNbO3multimode channel waveguides. The results indicate that the generally applied model of total internal reflection (TIR) is not suited to explain the low voltage operation of multimode X-switches. View full abstract»

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  • Stability analysis for a semiconductor laser in an external cavity

    Page(s): 1023 - 1032
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    A detailed theoretical analysis of stability is presented for a semiconductor laser in an external cavity. The limits of stable operation are determined as a function of the external cavity parameters and the linewidth enhancement factor α. Instability is related to jumps of the laser frequency between external cavity modes (frequency bistability) or to feedback-induced intensity pulsations due to the carrier density dependence of the refractive index. The limit of bistability is derived from the steady-state solutions of the rate equations and the intensity pulsation limit is obtained from a small-signal analysis. This analysis also gives the location of zeros in the system determinant and the resulting FM noise spectrum. For practical applications we emphasize the determination of the stable tuning range for the phase in the external cavity and the classification of the possible types of instability for various feedback levels. View full abstract»

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  • Limits on the single-pass higher harmonics FEL operation

    Page(s): 1003 - 1005
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    The Lawson-Penner limit is used to gain some insight on the best performances of a single-pass higher order harmonic FEL operation. It is pointed out that under suitable conditions, a low energy accelerating device may be used to obtain FEL operation in the visible or UV region. View full abstract»

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  • Stimulated Raman forward scattering with a divergent or convergent pump beam

    Page(s): 1065 - 1074
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    Stimulated Raman forward scattering is investigated for a divergent or convergent pump beam. The rate equations for this case are derived and analytically solved, including pump depletion. The solutions are compared to an experiment where the generation of a Stokes pulse from noise is investigated with a pump beam of variable divergence. Theoretical and experimental results are in good agreement. Stimulated Raman forward scattering thus may be controlled by the beam geometry, e.g., in Raman pulse compressors. An example is discussed in the Appendix. View full abstract»

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  • The nonlinear interaction between an electron and multimode fields in an electromagnetically pumped free electron laser

    Page(s): 1079 - 1085
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    We consider the motion of an electron under the influence of two counterpropagating multimode electromagnetic waves and a longitudinal electrostatic field. General equations of motion are presented from which a simple wavelength scaling condition is deduced for minimizing detrapping effects. An interaction coherence time or a maximum useful interaction length parameter is derived. The full equations of motion are numerically solved for a variety of external and initial conditions. View full abstract»

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Aims & Scope

The IEEE Journal of Quantum Electronics is dedicated to the publication of manuscripts reporting novel experimental or theoretical results in the broad field of the science and technology of quantum electronics..

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Aaron R. Hawkins
Brigham Young University