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Quantum Electronics, IEEE Journal of

Issue 5 • Date May 2002

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Displaying Results 1 - 11 of 11
  • Locked multichannel generation and management by use of a Fabry-Perot etalon in a mode-locked Cr:forsterite laser cavity

    Publication Year: 2002 , Page(s): 458 - 463
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (257 KB) |  | HTML iconHTML  

    We demonstrate a method to manage the locked multichannel output from a mode-locked Cr:forsterite laser cavity, which was achieved by inserting a Fabry-Perot etalon into the oscillator. It is found that the thickness of the etalon determines the channel spacing and its surface reflectivity affects channel linewidth and channel pulsewidth. Following Fabry-Perot theory, we can use these tracts to control the characteristics of these locked multichannels View full abstract»

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  • Results of small-signal gain measurements on a supersonic chemical oxygen iodine laser with an advanced nozzle bank

    Publication Year: 2002 , Page(s): 421 - 428
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (331 KB) |  | HTML iconHTML  

    High-resolution diode laser spectroscopy has been used to probe the gain in the active medium formed by an advanced supersonic chemical oxygen iodine laser (COIL), ejector nozzle bank. The probe beam was directed through the medium at 90° (normal) to the flow velocity and at an angle of 27.5° away from normal incidence. Analysis of the small-signal gain spectrum allowed for the determination of the gain, average gas velocity, static pressure, and temperature. The dependence of gain, temperature, and gas velocity on the primary nitrogen molar flow rate and basic hydrogen peroxide temperature was obtained. A maximum small-signal gain of 7 × 10-3 cm-1, average gas velocity of 575 m/s, static temperature of 172 K were measured for flow rates of 270 mmole/s of primary nitrogen, 39.2 mmole/s of chlorine, 11 mmole/s of secondary nitrogen, and 0.8 mmole/s of iodine. Estimation of the static pressure in the flow core from spectroscopic data is very close to the static sidewall pressure. The role of transverse velocity components in the gas flow and their effect on the interpretation of gain profiles is discussed View full abstract»

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  • CMOS-compatible planar silicon waveguide-grating-coupler photodetectors fabricated on silicon-on-insulator (SOI) substrates

    Publication Year: 2002 , Page(s): 477 - 480
    Cited by:  Papers (10)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (215 KB) |  | HTML iconHTML  

    We report planar silicon interdigitated p-i-n photodiodes with waveguide-grating couplers fabricated on silicon-on-insulator (SOI) substrates. The devices were fabricated in standard CMOS technology on 200-nm-thick SOI wafers with no additional fabrication steps. A waveguide-grating coupler with a period of 265 nm increased the quantum efficiency by a factor of four compared to a photodiode without a coupler. The dark current was 10 pA at -3-V bias and the bandwidth was 4.1 GHz (RC limited) View full abstract»

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  • An efficient and accurate method for gain spectrum calculations in non-identical multi-quantum-wells

    Publication Year: 2002 , Page(s): 495 - 499
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    This paper describes a semi-analytical approach, with no discretization, for gain spectrum calculations in multi-quantum-well structures, based on the Galerkin method. After a brief presentation of the physical model and development of our method, we show with some examples that this method is superior to the discretized finite-element method in terms of computation time View full abstract»

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  • Coherent microwave generation in a nonlinear photonic crystal

    Publication Year: 2002 , Page(s): 481 - 485
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB) |  | HTML iconHTML  

    We propose a new approach for generating coherent microwaves in a nonlinear photonic crystal through optical rectification. In a photonic crystal, the reciprocal vector and dispersion of the group velocity can be used to both compensate for the velocity mismatch between the generated microwave and the pump light. We show that coherent microwave radiation from kilohertz to terahertz can be generated through this approach by designing a suitable structure View full abstract»

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  • Electroabsorption modulated laser for long transmission spans

    Publication Year: 2002 , Page(s): 464 - 476
    Cited by:  Papers (22)  |  Patents (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (437 KB) |  | HTML iconHTML  

    Strain-compensated AlGaInAs quantum-well electroabsorption modulated lasers (EMLs) transmit at 10 Gbits/s on uncompensated transmission spans of >75 km of standard fiber and >225 km of MetroCor fiber. Details of the design, fabrication, and testing are presented. A complex-coupled distributed feedback (DFB) grating is used to enable high output power. The epitaxy and chip structure are described. The paper studies what is needed to accomplish long-span transmission in terms of minimum physical requirements for laser mode control, facet reflection, index grating strength, laser-modulator matching, laser-modulator electrical isolation, modulator extinction ratio, modulator capacitance, linewidth enhancement factor, etc. The interaction of the modulator with the laser is analyzed and a requirement for this structure is computed for the electrical isolation resistance between modulator and laser contacts. Stability of the laser source is discussed and a method is derived for determining the grating's gain-coupling coefficient at operating power. Chirp due to the modulator is analyzed. Nonzero chirp of the modulator is shown to have beneficial impact on the quality of the signal after transmission. The effect of a bias-dependent alpha parameter is analyzed. Because bit-error rate is a strong function of mean alpha parameter and not a strong function of the range of alpha during nonreturn-to-zero modulation, we determine that tuning the chirp of the EML modulator to suit different fiber types (MetroCor, SMF-28, etc.) is practical. Specific tradeoffs are also required. Experimental results verify the analysis View full abstract»

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  • Broadly wavelength-tunable external cavity, mid-infrared quantum cascade lasers

    Publication Year: 2002 , Page(s): 486 - 494
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    Wavelength tuning over 120 nm for a grating-coupled 5.1-μm quantum-cascade type-I laser was studied for temperature from 80 to 243 K (-30°C). Both the Littman-Metcalf and first-order grating direct feedback cavity configurations were used with similar tuning results. The goal is to achieve broad tunability, and the result is a combined grating and temperature tuning of 245 nm, from 5.040 to 5.285 μm. The laser was designed for predominantly single-mode or at most, two-longitudinal mode operation. The instrument-limited laser linewidth was less than the cavity longitudinal mode spacing. Stepping-motor control of the grating allowed 0.4-GHz wavelength increments (35 pm) to be realized with high reproducibility. A current-induced wavelength shift of ~2-3 GHz was observed, corresponding to an effective refractive index change of ~10-3. Analysis indicates that single-mode, continuously tunable operation is feasible with a more optimal device and cavity View full abstract»

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  • Electrically tunable, optically induced dynamic and permanent gratings in dye-doped liquid crystals

    Publication Year: 2002 , Page(s): 451 - 457
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB) |  | HTML iconHTML  

    We report on further experimental studies of the ac field response of transient and permanent gratings written with visible light in both planar and homeotropic, dye-doped liquid crystal cells. It is found that the diffraction efficiency of these gratings can be controlled by the applied ac field. High ac frequencies can switch off diffraction completely in both permanent and transient gratings. The response time to the applied electric field is shown to be in the range of milliseconds. Permanent gratings persist for months and, when heated above the liquid crystal phase transition temperature, they can be only partially erased. Furthermore, on cooling the diffraction efficiency can be restored, indicating a strong anchoring at the boundaries of the cell View full abstract»

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  • Influence of Si-doping on the characteristics of InGaN-GaN multiple quantum-well blue light emitting diodes

    Publication Year: 2002 , Page(s): 446 - 450
    Cited by:  Papers (67)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    A detailed study on the effects of Si-doping in the GaN barrier layers of InGaN-GaN multiquantum well (MQW) light-emitting diodes (LEDs) has been performed. Compared with unintentionally doped samples, X-ray diffraction results indicate that Si-doping in barrier layers can improve the crystal and interfacial qualities of the InGaN-GaN MQW LEDs. It was also found that the forward voltage is 3.5 and 4.52 V, the 20-mA luminous intensity is 36.1 and 25.1 mcd for LEDs with a Si-doped barrier and an unintentionally doped barrier, respectively. These results suggests that one can significantly improve the performance of InGaN-GaN MQW LEDs by introducing Si doping in the GaN barrier layers View full abstract»

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  • New short-wavelength laser emissions from optically pumped 13 CD3OD

    Publication Year: 2002 , Page(s): 429 - 431
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (205 KB) |  | HTML iconHTML  

    We report the discovery of 15 new laser emissions from 13 CD3OD when optically pumped with a CW CO2 laser. The wavelengths of these lines, ranging from 57.5 to 135.2 μm, are reported along with their polarization relative to the CO2 pump laser, operating pressure and relative intensity. A three-laser heterodyne system was then used to measure the frequencies of 12 optically pumped laser emissions from this methanol isotope. These emissions range from 65.7 to 151.8 μm and are reported with fractional uncertainties up to 2·10-7 View full abstract»

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  • Theory of spectral beam combining of fiber lasers

    Publication Year: 2002 , Page(s): 432 - 445
    Cited by:  Papers (15)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    We model the spectral beam combining of a fiber laser array in the external resonator configuration, as proposed by V. Daneu et al. A diffraction integral-based approach is used that leads to design principles for most significant measures of performance, such as efficiency, bandwidth, and beam quality. Sensitivity to alignment and positioning errors is also characterized. Off-axis transform lens aberrations are shown to limit array size, and two design criteria are applied to compare the performance of simple spherical, compound, and aspheric lenses. The results indicate that a simple aspheric lens is superior in meeting the proposed criteria to a well-designed compound (quadruplet) lens with spherical surfaces. Application to the efficient coupling of a laser array to a multimode fiber core is discussed as a final example 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