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Quantum Electronics, IEEE Journal of

Issue 9 • Date Sep 1992

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Displaying Results 1 - 16 of 16
  • A 5 kW CW CO2 laser using a novel negative-branch unstable resonator with a phase-unifying output coupler

    Publication Year: 1992 , Page(s): 1855 - 1858
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    A 5 kW CW CO2 laser using a negative-branch unstable resonator (M=-1.5) is proposed and characterized experimentally. The resonator consists of a stepwise variable reflecting output coupler, called the phase-unifying output coupler, and a total reflector. A 5 kW CW laser beam with diffraction limited quality (2θ=0.45 mrad) is obtained and affected by the focal point in the resonator. The misalignment angle to reduce the laser power to 95% is improved by a factor of 19 compared with a positive-branch unstable resonator (M=1.5) with a phase-unifying output coupler at the same resonator length View full abstract»

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  • The stimulated Raman scattering threshold for a nondiffraction-limited pump beam

    Publication Year: 1992 , Page(s): 1930 - 1936
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (660 KB)  

    The threshold power of stimulated Raman scattering (SRS) has been calculated for various nondiffraction-limited pump beams using a numerical model. These calculations were performed for the following pump beam profiles: Gaussian-Hermite, Gaussian-Laguerre, Gaussian-Schell-model (GSM), and several superpositions of Gaussian-Hermite modes. It is shown that the threshold power, for a tightly focused beam, depends on the M2 factor, which is a dimensionless factor that compares the divergence of a given beam with the divergence of a (diffraction-limited) Gaussian beam, related to the pump beam quality. The influence of the exact pump beam profile on the threshold is small. It is shown that the measured SRS thresholds in methane for two pump beams, one with an M2 of 1.12 and the other with M2=8.7, correspond with the calculated thresholds for two GSM beams with the same M2 View full abstract»

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  • Modeling the static and dynamic behavior of quarter-wave-shifted DFB lasers

    Publication Year: 1992 , Page(s): 1874 - 1883
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    High-coupling (grating coupling constant=3.0) phase-shifted distributed-feedback (DFB) lasers are studied using a transmission-line laser model (TTLM) which includes spatial hole burning (SHB), the material gain spectrum, refractive index dependence on carrier concentration, and random spontaneous emission. Good agreement for CW spectra is shown with other models and experimental results. Dynamic simulation of laser transients shows SHB-induced deterministic mode hopping and chirping at moderate output powers. The effects of mode hopping and chirping on system performance are studied using a laser model combined with a fiber model View full abstract»

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  • Piezoelectrically induced optical phase modulation of light in single-mode fibers

    Publication Year: 1992 , Page(s): 1901 - 1908
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB)  

    Optical phase modulation induced in piezoelectric copolymer, vinylidene fluoride (73 mol.%)/trifluoroethylene (27 mol.%), coated single-mode fibers has been examined and analyzed from both experimental and theoretical aspects. High-sensitive phase modulation, which is more than four times as large as those of vinylidene fluoride/tetrafluoroethylene copolymer, is obtained over a flat response range from 10 kHz to 3 MHz. At frequencies below 7 kHz and higher than 6 MHz the optical responses are dominated by axial and radial resonances, respectively, of the fiber-jacket composite. The theoretical prediction on induced phase shifts at high frequencies is carried out based on radial vibration analysis and followed by the experimental results View full abstract»

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  • Plasma electronics in pulsed nitrogen lasers

    Publication Year: 1992 , Page(s): 1937 - 1940
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    A detailed study showing that the electronic impedances of both the spark gap and the laser channel plasmas play an integral part in the overall discharge circuit of a pulsed nitrogen laser is presented. The electronic properties of these plasmas can critically determine the temporal width of the laser pulse View full abstract»

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  • Design considerations and operating characteristics of high-power active grating-surface-emitting amplifiers

    Publication Year: 1992 , Page(s): 1884 - 1893
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB)  

    An analysis of the characteristics and optimization of the design parameters of active-grating surface emitting amplifiers is presented. It is concluded that coherent power outputs of more than 1 W with ⩽30 dB of amplified spontaneous emission noise power contained in the far-field beam divergence of the coherent output are expected for amplifier lengths greater than 0.5 cm. The effects of end reflections on the active-grating amplifier power output are also considered, and it is found that end reflections of 10-3 or less should have a negligible effect on the power output View full abstract»

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  • Experimental study of stimulated Brillouin scattering by broad-band pumping

    Publication Year: 1992 , Page(s): 1859 - 1863
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    A XeCl laser system has been used to investigate stimulated Brillouin scattering (SBS) cyclohexane and methanol with laser radiation of spectral width Δνp much larger than the bandwidth of the excited acoustic wave Δνa. The reflectivity and the phase conjugation (PC) fidelity of the SBS reflector versus pump intensity and bandwidth have been measured. It is shown experimentally that the PC fidelity and the reflectivity are strongly dependent on the pump spectral width and intensity. However, the experimental results show that the use of a liquid SBS reflector is still effective for correcting the spatial aberrations of laser radiation with Δν p≃30 Δνa in a double-pass amplifier View full abstract»

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  • Quasi-phase-matched second harmonic generation in a LiTaO3 waveguide

    Publication Year: 1992 , Page(s): 1909 - 1914
    Cited by:  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (492 KB)  

    The authors report third-order quasi-matched (QPM) second harmonic generation (SHG) in a LiTaO3 channel waveguide. A deep domain-inverted region is first fabricated by a proton-exchange and heat treatment technique. Then a uniform and low-pass channel waveguide is fabricated by pyrophosphoric acid proton exchange. Consequently, 12 mW of blue light is obtained at 424 nm wavelength with a conversion efficiency of 6%. The observed FWHM (full-width half maximum) temperature acceptance width for SHG power is 3.2°C and FWHM wavelength acceptance bandwidth for that is 0.2 nm. It is also shown that diffraction limited focusing of the generated blue light may be obtained View full abstract»

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  • Distributed out-coupling of second harmonic generation in a waveguide via nonresonant first-order corrugation

    Publication Year: 1992 , Page(s): 1848 - 1854
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    In some waveguide materials, strong second-order optical nonlinearity is accompanied by strong harmonic propagation loss, particularly due to absorption. The conversion efficiency of such waveguides can be significantly enhanced by using a distributed out-coupling via a nonresonant first-order corrugation. Analysis of the proposed device is carried out using a coupled-mode approach. The results indicate that in certain cases, the second harmonic generation may be enhanced up to few orders of magnitude. The proposed scheme appears to be efficient mainly in phase-matched situations with moderate harmonic loss (up to about 100 cm-1). The far field of the proposed surface emitting device is diffraction limited View full abstract»

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  • Gain of TE-TM modes in quantum-well lasers

    Publication Year: 1992 , Page(s): 1864 - 1873
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    Semiclassical laser theory is rigorously applied to semiconductor lasers in order to obtain both the complete TE and TM linear gain. The resulting expressions for the modal gain in heterostructure lasers differ in form from those conventionally accepted. In particular, the conventional modal gain written as the product of a confinement factor and a bulk gain is only an approximation of the true modal gain derived. The conventional expression relies on an explicit definition of the active region of the laser, which can be ambiguous when certain heterostructures, such as parabolic quantum wells, are to be treated. This ambiguity is eliminated by the gain expressions as a more natural active region defined by the product of electron and hole wave functions emerges. The relevant approximations which allow the newly derived gain equations to be written in forms similar to the conventional expressions for single quantum well, multiquantum well (MQW), and in wide active region lasers are explicitly shown View full abstract»

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  • A self-consistent model for negative glow discharge lasers: the hollow cathode helium mercury laser

    Publication Year: 1992 , Page(s): 1941 - 1956
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1412 KB)  

    A model for negative glow metal-vapor ion lasers that self-consistently describes the dynamics of the negative glow and the cathode sheath regions of the discharge has been developed. The model computes the electron energy distribution and the population of relevant excited states in the negative glow self-consistently with the charged particles fluxes and electric field distribution in the cathode sheath. Its application to the study of the helium-mercury charge transfer ion laser is reported. The model accurately depicts the operation of a hollow cathode in the laboratory, where for a defined cathode geometry and material, the discharge characteristics are determined by the selected discharge voltage and the gas pressure. The laser output power calculated as a function of the discharge parameters is in good agreement with experimental measurements reported in the literature. The model can be modified to simulate other negative glow discharge lasers, such as electron-beam pumped CW ion lasers View full abstract»

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  • Noise study of low-dimensional quantum-well semiconductor laser amplifiers

    Publication Year: 1992 , Page(s): 1894 - 1900
    Cited by:  Papers (4)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    Low noise characteristics of semiconductor laser amplifiers (SLAs) consisting of low-dimensional quantum-well structures are obtained theoretically using density matrix theory. Due to a sharper gain spectrum as well as a smaller population inversion parameter in quantum-wire and quantum-box structures, predominant two beat noises of traveling-wave SLAs were found to be reduced in the lower dimensional quantum-well structures, even in solitary devices without a narrow bandpass filter. The noise figure can be reduced to 3.3 dB in a quantum-box structure, which nears the theoretical limit of 3 dB View full abstract»

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  • The Rayleigh scattering loss of isotropic weakly guiding single-mode waveguides

    Publication Year: 1992 , Page(s): 1844 - 1847
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    The relation between the Rayleigh scattering loss and the Laplacian mode-field-half-width (MFHW) is derived. It is shown that not only the Rayleigh scattering loss but also the transverse offset loss, the angular misalignment loss, and the microbending loss will be small if the field distribution is similar to an elliptic-Gaussian distribution View full abstract»

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  • Femtosecond soliton transmission characteristics in an ultralong erbium-doped fiber amplifier with different pumping configurations

    Publication Year: 1992 , Page(s): 1922 - 1929
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    The transmission characteristics of femtosecond optical solitons in an 18.2 km-long erbium-doped fiber amplifier (EDFA) have been investigated in detail by changing the pumping configuration. With backward pumping, a lossless transmission of 440 fs solitons at 1.55 μm has been realized with a pump power of 16 mW. The output pulsewidth is determined by the spectrum modified by the soliton self-frequency shift. In a bidirectional pumping configuration, 440-fs soliton pulses have been transmitted for a total pump power of 38 mW, where the output pulse width is determined by the original 1.55 μm spectrum. Although a femtosecond soliton is very weakly trapped in the EDFA-gain bandwidth of 1.55 μm and the soliton self-frequency shift inevitably occurs, the femtosecond pulse component still exists at 1.55 μm, and a pulse can be successfully transmitted with a gain of 11 dB and very little pulse broadening View full abstract»

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  • Two- and four-wave mixing with saturable absorption and gain

    Publication Year: 1992 , Page(s): 1915 - 1921
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    An exact solution to a model of two- and four-wave mixing in photorefractive media with saturable gain and absorption is presented. Pump depletion effects are accounted for, and the procedure for matching two-point boundary conditions is given. Possibilities of multistable solutions are investigated, and procedures on how to deal with such situations are outlined. It is found that the energy transfer between waves is less effective in the nonsaturated regime as compared to the saturated regime. It is also established that the nonsaturated system is more stable than the saturated under the same conditions View full abstract»

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  • Modulation instability in highly birefringent optical fibers: a coupled-mode analysis

    Publication Year: 1992 , Page(s): 1838 - 1843
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    The self- and cross-phase modulation instabilities (SPMI and XPMI) of the orthogonally polarized beams in high birefringent optical fibers are studied in detail by a coupled-mode theory in the frequency domain. This approach is mathematically identical to the perturbation method in the time domain, but lends itself to a clear insight of the physical process. It is noted that the phase-matching conditions are critical in the interactions between sideband components. By identifying these phase-matching conditions, possible patterns and the gains and positions of the peak gains of modulation instabilities may be well predicted by simple analytical expressions, which have been verified by the more rigorous full-wave solutions 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..

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Meet Our Editors

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