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Quantum Electronics, IEEE Journal of

Issue 7 • Date July 1991

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Displaying Results 1 - 12 of 12
  • Surface-normal electroabsorption reflection modulators using asymmetric Fabry-Perot structures

    Publication Year: 1991 , Page(s): 1922 - 1931
    Cited by:  Papers (25)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1099 KB)  

    The authors discuss a family of surface-normal electrooptic reflection modulators using asymmetric Fabry-Perot (ASFP) structures with GaAs-AlGaAs multiple quantum wells (MQWs) as the active medium. When an optimized top mirror reflectivity ( approximately 75%) is used, a voltage swing as low as 2 V is enough to change the device reflectivity by more than 40% with a contrast ratio of 50. A comparison with various Fabry-Perot structures shows that the ASFP is the best structure in terms of its operating voltage requirement and optical bandwidth. A sensitivity analysis shows that tolerances of 2 nm in operating wavelength, 0.5 V in operating voltage, 0.3% in layer thickness control or 10 degrees C in temperature variation can be expected from ASFPs with a finesse approximately 10.<> View full abstract»

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  • Dynamics of the transient buildup of emission in Nd3+-doped fiber lasers

    Publication Year: 1991 , Page(s): 1910 - 1921
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (916 KB)  

    The two-stage process of the transient buildup of emission in Nd 4+-doped fiber lasers is described both experimentally and theoretically. After switching on the pump, spontaneous emission increases first until the gain becomes sufficient to compensate for the cavity losses; the laser field then develops and reaches the steady state after more or less regular oscillations. During this second stage, an almost chaotic spiking is obtained either for high pumping rates and/or at low temperatures. The whole set of these dynamical scenarios is not described under the usual assumptions of uniform cavity losses over the whole field spectrum and of pure homogeneous broadening for the transition line, but rather a modified form of the Maxwell-Bloch equations which retains some frequency dependence for the losses in the cavity and the inhomogeneous broadening as well is proposed View full abstract»

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  • Discharge-induced frequency modulation of RF excited CO2 waveguide lasers

    Publication Year: 1991 , Page(s): 1939 - 1945
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    The mechanisms causing a shift in the oscillation frequency of an RF-excited CO2 waveguide laser through changes in the discharge excitation power are investigated. Frequency shifts in the range of ±0.5 to 1 MHz per watt of RF input power were measured. These are shown to be consistent with the effects of thermal expansion of the laser gas caused by an increase of the gas temperature due to RF power absorption. It is also shown that the effects of gas dissociation are small but significant, whereas, contrary to earlier suggestions, the effects of electron density fluctuations are negligible. The discharge-induced frequency shift may be used as a simple frequency modulator with a frequency deviation of ±30 MHz, although the usefulness of this effect is limited to a bandwidth of about 500 Hz, due to the acoustic resonance of the waveguide channel View full abstract»

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  • Analysis of TE and TM modes in DFB lasers by two-dimensional theory

    Publication Year: 1991 , Page(s): 1874 - 1885
    Cited by:  Papers (1)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (820 KB)  

    The two-dimensional theory of a distributed feedback (DFB) laser (which was previously presented and applied to the analysis of the laser threshold conditions for the transverse-electric (TE) mode in a simple three-layer waveguide structure) is developed to treat both TE and transverse-magnetic (TM) modes in a four-layer waveguide structure with a thin grating layer, which more closely reflects actual DFB laser structure. The differences between TE and TM modes for the dispersion relations and the laser threshold conditions are clarified. The effects of the waveguide structure (including grating layer thickness, refractive indexes of layers, coupling constant, and corrugation period) on the threshold gains and the gain differences between the two longitudinal modes on both sides of the Bragg frequencies are studied in detail for both TE and TM modes View full abstract»

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  • CW high power single-lobed far-field operation of long-cavity AlGaAs-GaAs single-quantum-well laser diodes grown by MOCVD

    Publication Year: 1991 , Page(s): 1859 - 1862
    Cited by:  Papers (3)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    Data on long-cavity 100-μm-wide broad-stripe laser diodes that lase with a barrow single-lobed far-field pattern in continuous room-temperature operation are presented. Diodes with a cavity length of 1250 μm emit a power of 200 mW per facet into a 2.5° lobe (full width at half maximum). Short-cavity devices (cavity length of 350 μm) lase with a continuously increasing number of lateral modes right from threshold, and exhibit a far-field divergence that is over three times greater than that of 1250-μm diodes. Explanations for the effect of increasing cavity length on the field patterns of these devices are proposed, based on the measured increase in injected carrier diffusion length in long-cavity diodes and the influence of thermal waveguiding and mirror losses on intermodel discrimination View full abstract»

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  • Computer model of the electron-beam excited XeF(B-X ) laser

    Publication Year: 1991 , Page(s): 1946 - 1953
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    The authors report results on the computer simulation of electron-beam pumped XeF lasers user common conditions, as well as under elevated temperature and high pumping rates that are known to improve laser performance. The Boltzmann equation for the electron energy distribution function and the chemical kinetics equations were solved in a consistent manner. The model took into account five vibrational levels of the electronic B state and seven levels for the C and X states of the XeF molecule. The model used gives reasonable agreement with the results of small signal gain measurements. A method of taking into account the finite rate of rotational relaxation makes it possible to obtain time dependencies of the lasing power in different spectral bands that qualitatively agree with those measured in experiments at different temperatures and pump rates View full abstract»

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  • Optically self-locked semiconductor laser with servo control for feedback phase and laser current

    Publication Year: 1991 , Page(s): 1863 - 1868
    Cited by:  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    The operating current of a semiconductor laser optically locked to a high-finesse reference cavity can be controlled using a second-harmonic lock-in technique. The authors present theoretical calculations for this novel servo scheme. For stabilization and noise reduction of semiconductor lasers, the optical lock to a high-finesse cavity with a feedback phase servo has become a standard technique. An additional servo for the laser current is desirable for combining good tuning capability and high spectral purity. It is demonstrated that such a servo can easily be established with no changes in the optical setup. The practical applicability of this technique has been demonstrated in a setup with a 780-mm laser diode View full abstract»

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  • Power exchange in tapered optical couplers

    Publication Year: 1991 , Page(s): 1932 - 1938
    Cited by:  Papers (9)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    The power exchange between nonparallel optical waveguides or tapered couplers is analyzed by the coupled-mode theory based on local modes of the individual waveguides (local waveguide modes). A self-consistent nonorthogonal coupled-mode formulation is presented and transformed into an orthogonal form which is equivalent to the coupled-mode equations for the local modes of the coupled waveguides (local array modes). The coupled-mode equations are then solved numerically and the effect of the taper on the power exchange between the two guides is studied View full abstract»

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  • Analysis of monolithic integrated master oscillator power amplifiers

    Publication Year: 1991 , Page(s): 1900 - 1909
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (832 KB)  

    An analysis of a novel, monolithic integrated master oscillator power amplifier (M-MOPA) is presented. The M-MOPA consists of a DBR master oscillator which injects power into a linear chain of amplifiers and detuned second-order grating output couplers. The analysis self-consistently includes amplified spontaneous emission buildup and residual reflections throughout the amplifier stages. It predicts that output powers in excess of 1 W can be expected from a single-lateral-mode waveguide multistage amplifier less than 1 cm in length, injected with less than 15 mW of input power. In addition to the signal gain of >25 dB, the signal-to-noise ratio at 1-W output exceeds 15 dB. Because of the small reflections associated with the grating output couplers, and gain saturation by the injected signal, the amplifier self-oscillation threshold is suppressed to current densities above 15 kA/cm2 View full abstract»

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  • FM mode-locked high-pressure CW RF-excited CO2 waveguide laser

    Publication Year: 1991 , Page(s): 1869 - 1873
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    The authors report the results from a study of a FM mode-locked continuous-wave (CW) RF-excited CO2 waveguide laser operated at 0.25-2 atm gas pressures. It is shown that electrooptic FM modulations can be efficiently used to mode lock a CW CO2 laser. The combination of a high gas pressure and a high modulation frequency makes it possible to generate pulses which are substantially shorter than those previously reported for CW mode-locked CO2 lasers. A theoretical approach is used for simulation of the FM mode-locked laser. The experimental pulses of a few hundred picoseconds FWHM are considerably shorter than previously reported for CW mode-locked CO2 lasers. The experimental results are compared with the results of numerical calculations using a frequency domain simulation model View full abstract»

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  • CW injection seeding of a modelocked semiconductor laser

    Publication Year: 1991 , Page(s): 1854 - 1858
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    The authors extended the injection locking technique to control the output of a modelocked semiconductor laser with an external continuous-wave (CW) signal. With this injection seeding technique, over 8 mW of average power in 30 ps pulses with side cluster suppression of over 20 dB was obtained from an actively modelocked AlGaAs semiconductor laser. This average output power compares favorably with the 12 mW W output power of the extended resonator. The frequency spectrum of the laser is determined by the background noise level as set by the spontaneous emission. Injection seeding overrides the noise and concentrates over 99% of the available energy in a single nearly transform-limited pulse View full abstract»

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  • A self-consistent model of a nonplanar quantum-well periodic laser array

    Publication Year: 1991 , Page(s): 1886 - 1899
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1204 KB)  

    An analysis of a nonplanar semiconductor periodic laser array is carried out using a self-consistent model that successfully explains the experimentally observed efficiencies and output optical patterns. This model takes into account the two-dimensional injected current distribution coupled with the optical intensity profile and gain variation from the mesa to the groove. The optical field distribution of the nonplanar laser array is treated as a linear combination of the optical modes in the mesas, grooves, and bends using the effective index method. Numerical results show the multimode operation due to spatial hole burning, the near-field patterns affected by the nonuniform current injection, and the competition of available carriers among the modes of neighboring waveguides 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