By Topic

Solid-State and Electron Devices, IEE Proceedings I

Issue 6 • Date December 1982

Filter Results

Displaying Results 1 - 20 of 20
  • Semiconductor injection lasers and their applications

    Save to Project icon | PDF file iconPDF (148 KB)  
    Freely Available from IEEE
  • Long-wavelength PbSnTe-PbTeSe lattice-matched single-heterestructure lasers grown by LPE

    Page(s): 203 - 207
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (794 KB)  

    Properties of Pb1 ¿ xSnxTe-PbTe1¿ySey lattice-matched single-heterostructure (SH) diode lasers grown on Pb1 ¿ xSnxTe substrates by liquid-phase epitaxy were studied for various compositions in the range 0.13<x<0.24, which corresponds to a wavelength range of 12 ¿m to 18.5 ¿m (at T = 20K). Threshold current density Jth was measured as a function of temperature from 10K to 140K, and was found to be comparable to that observed previously in PbSnTe-PbTeSe and PbSnTeSe-PbTeSe DH lasers. An external differential quantum efficiency of 1¿2% was measured in these lasers. The emission spectra of the SH lasers frequently show a single-mode structure for J<2Jth at high temperatures. Measurements of I/V characteristics carried out in these lasers suggest that tunnelling currents contribute significantly to the observed threshold current density. At high temperatures, characteristic temperatures To in the range 16.5 to 21 K were measured. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Formation of a long-wavelength buried-crescent laser structure on channelled substrates

    Page(s): 209 - 213
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (858 KB)  

    A laser structure, in which a cresent-shaped GaInAsP active region is isolated within a channel chemically etched in an InP substrate, has been formed in a single stage of liquid-phase epitaxial growth. The growth process was influenced, first, by the magnitude and uniformity of the channel width, cross-section and depth, and, secondly, by melt super-saturation. High strength mask-to-substrate adhesion and low super-saturation were necessary for the reproducible formation of the structure. Lasers with pulsed threshold currents of 30¿40 mA at ¿ 25°C have been obtained, and stable zero-order transverse-mode CW operation was possible up to at least 9 mW. These lasers have operated successfully in experimental optical-fibre transmission systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Assessment of advanced laser structures by photoluminescence

    Page(s): 214 - 217
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2722 KB)  

    A photoluminescence system has been developed for use in the 1.2 to 2.0 ¿m wavelength range for the rapid nondestructive evaluation of epitaxial layer structures prior to semiconductor laser fabrication. This system, which has high spatial and spectral resolution, is used to examine narrow-active-layer stripes of double-heterostructure GaInAsP material intended for 1.3 and 1.5 ¿m lasers. The technique permits assessment of entire wafers, and gives advance information on probable yields and wavelengths of fully fabricated devices. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimum designs for InGaAsP/InP (λ = 1.3μm) planoconvex waveguide lasers under lasing conditions

    Page(s): 218 - 228
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1603 KB)  

    Lasing characteristics for 1.3 μm InGaAsP/InP planoconvex waveguide (PCW) lasers were investigated both theoretically and experimentally. Fundamental lateral transverse-mode stability, light-output/ current characteristics, including threshold current and external differential quantum efficiency, and fundamental- mode intensity profiles were investigated up to a high injection-current level by using PCW lasers with individually varying structural design parameters. The experimental results were in good agreement with calculations, which were carried out taking into account carrier outdiffusion along the junction plane and spatial hole burning and their effects on the waveguiding. It was found that a narrow groove width (narrow channel), a relatively large built-in effective refractive index difference and a narrow injection current region width are the main PCW structural design conditions responsible for the high-quality lasing characteristics. The experimental results revealed that high-quality 1.3 μm InGaAsP/InP narrow-channel PCW lasers with 2.5 μm groove width show stable fundamental lateral transverse mode operation up to three times the threshold current, at which 25 m W output power from a facet is attained under CW operation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Gain spectra of quaternary semiconductors

    Page(s): 229 - 236
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1101 KB)  

    A simple analytical model is applied to predict gain spectra of InGaAsP quaternary alloys. Band-to-band recombination between parabolic bands with no K-selection is assumed, with contributions from both heavy and light hole bands taken into account. An effective bandgap energy varying with the carrier concentration accounts for the bandgap shrinkage effect. The gain function is calculated analytically in terms of carrier concentration via the approximations of Marinelli, Unger, and Joyce and Dixon. Comparison of calculated results with available data shows good agreement between theory and experiment. The dependence of gain spectra on carrier concentration, doping and alloy composition is discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Single-mode lasers for optical communications

    Page(s): 237 - 251
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2076 KB)  

    The intended fibre-optic applications for both short- and long-wavelength single-mode diode lasers are discussed. Major types of single-mode devices are grouped and described in two Sections: lowpower (1¿7 mW/facet) lasers and high-power (10¿50 mW/facet) lasers. The low-power laser Section contains principles of fundamental-mode stabilisation, and a treatment in parallel of AlGaAs and InGaAsP buriedmesa, nonplanar-substrate and laterally lossy devices. The high-power laser Section contains the various means of achieving high-power reliable single-mode operation and a description and comparison of major types of high-power AlGaAs devices. Emphasis is placed on the performance of the constricted doubleheterojunction large-optical-cavity (CDH-LOC) laser. A discussion of single-longitudinal-mode stabilisation and device dynamic behaviour is also presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 'Nonwaveguide'-mode semiconductor injection lasers

    Page(s): 252 - 255
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (501 KB)  

    Double-heterostructure AlGaAs (λ = 0.83 μm) and GaInPAs/InP (λ = 1.26 μm) injection lasers, operating in a 'nonwaveguide' mode have been prepared and studied. The axis of a Fabry-Pérot cavity was inclined to the active layer plane, and so laser emission had to penetrate through the transparent widebandgap cladding layers of the heterostructure. Tilting angles were chosen from 10° to 15° to prevent waveguide propagation of laser emission along the active layer. Laser action with pulse excitation, including room-temperature operation at λ = 1.26 μm, was observed, and the divergence of the laser beam was found to be several times less in the nonwaveguide configuration (5-8°) than in the usual device (40-50°). Threshold current considerations and comments on device preparation are also given. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Pulsed-power performance and stability of 880 nm GaAlAs/GaAs oxide-stripe lasers

    Page(s): 256 - 261
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (875 KB)  

    The paper gives the results of an experimental and theoretical investigation of GaAlAs/GaAs oxidestripe lasers under high-pulsed-power conditions. At a pulsewidth of 18 ns the best samples delivered optical powers of more than 2 W per facet. The kink-free light/current characteristics, the well-behaved far-fields and the very-small-amplitude jitter in the optical pulse indicate a stable operation in the fundamental lateral mode up to the maximum power level. The maximum available power is found to vary less than the inverse square root of the pulse width between 20 ns and 1 ¿s. Catastrophic failure of these lasers is always accompanied with damage to one or both of the Al2O3-coated mirrors. The experimental power-law dependence and the distinct levels of power limit for lasers with differently prepared mirrors can be explained by a model which assumes a heat source in the mirror plane originating from nonradiative carrier recombination at the surface. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A survey of optical nonlinearities theory and observation in (AlGa)As injection lasers

    Page(s): 262 - 266
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (817 KB)  

    As a guide to understanding laser spectra, the results of published theories of nonlinear interactions in injection lasers are expressed in terms of a dimensional constant P¿, the power at which the effective steady-state gain, i.e.(gain/loss), at fixed junction voltage is halved. An analytical expression for P¿ is derived; with it the numerical value of P¿ corresponding to any particular theoretical model of optical nonlinearity can be deduced. This permits quantitative comparison of the strengths of the various model nonlinearities with each other as well as with experimental observation on actual devices. The paper deduces P¿ from the published analysis of two-photon absorption and of several formulations of spatial and spectral hole burning. Tabulations of the general expressions for P¿, of numerical values calculated for particular devices, and of observed values, indicate which interactions might be affecting the spectra of specific lasers. They also suggest experimental tests of nonlinear models. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Correlated laser spectral and intensity noise in short-path-difference interferometers

    Page(s): 267 - 270
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (487 KB)  

    A novel technique has been developed for stabilising against drift and vibration the path difference of a Michelson two-path interferometer. The technique has enabled measurements to be made for the first time of semiconductor laser noise around individual interference fringes near to, and including, zero order. Minimum noise was not detected at zero path difference as had been expected: this characteristic may be explained by assuming partial correlation between the source intensity and demodulated spectral noises. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Longitudinal mode competition in semiconductor lasers: Rate equations revisited

    Page(s): 271 - 274
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    Multimode rate equations have been used to investigate the response to a step current pulse of a semiconductor laser with built-in lateral waveguide. General expressions are given for the frequency and damping time of relaxation oscillations allowing for both gain and total spontaneous emission rate to have arbitrary dependences on carrier concentration. The exchange of power between dominant longitudinal modes, which occurs as a result of the peak gain shift with oscillating carrier concentration, is shown to occur on a time scale controlled by the damping time. The power exchange and the eventual domination by one or other mode are extremely sensitive to one key parameter ¿ the wavelength displacement between peak gain and the adjacent Fabry-Pérot mode. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-rate amplitude and frequency modulation of semiconductor lasers

    Page(s): 275 - 282
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1039 KB)  

    The paper discusses the amplitude and frequency modulation characteristics of directly modulated semiconductor lasers, with emphasis on their application to the optical control of microwave semiconductor devices. Measurements of the amplitude and frequency modulation performance of a double-heterostructure GaAs/GaAlAs laser at frequencies between 2 and 3 GHz are presented. A simple theory of laser frequency modulation is developed, and is shown to be in good agreement with the experimental results. High-level modulation is shown to have a severe effect on the laser mode structure. Suggestions are made for optimising the high-frequency modulation performance of semiconductor lasers. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Gain-switched pulse generation with semiconductor lasers

    Page(s): 283 - 290
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (799 KB)  

    The generation of picosecond optical pulses using the gain-switching method is examined using two different types of current drive at 1 GHz: short-pulse drive and sinusoidal (hard RF drive). The temporal and spectral characteristics of the resulting pulses are compared. The influence of the photon lifetime in the laser cavity has been examined for both types of drive, and it is shown that the shorter the photon lifetime then the shorter the output pulse. Simple numerical simulations are shown to give useful qualitative agreement within the limits of the model, but suggest that a limiting value of gain should be included. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Closely coupled twin-stripe lasers

    Page(s): 291 - 296
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (650 KB)  

    The paper reports on novel effects exhibited by closely coupled twin-stripe lasers, Two forms of bistability have been observed. One effect is possibly caused by switching of waveguiding mechanisms from gain guiding to self-focusing. The second mechanism exhibits a large shift in near-field distribution from one side of the laser to the other. The speed of this bistable switching has been found to be between 800 and 900 ps. The effect of optical injection on bistability is also noted. Finally, twin-stripe lasers allow picosecond pulses as short as 20 ps to be generated, and the paper records the dependence of picosecond pulsewidth on asymmetric waveguiding. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical limiter action in twin-stripe-geometry lasers

    Page(s): 297 - 300
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (566 KB)  

    Twin-stripe-geometry lasers subject to optical injection are analysed theoretically in terms of optical output power and injection current. The requirements on optical input power for the achievement of near-field movement are considered. A mode of device operation is found in which optical limiter action is obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effects of cavity length on 20 μm stripe laser waveguiding

    Page(s): 301 - 305
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    Measurements have been made on a number of lasers, cleaved to different lengths, but otherwise identical. The lasers used were simple planar oxide-insulated devices with stripe widths of about 18 nm and lengths from 225 to 600μm. The parameters measured were: threshold current, maximum power for zero-order-mode operation, and near-field widths (parallel to the junction). The variations of measurable parameters with length are shown to agree with first-order theory. A sophisticated numerical model has also been used to calculate the variables measured, using only material parameters and device dimensions. The values obtained are generally in good agreement with those measured, showing that, despite the complex behaviourof this weakly guided device, it is possible to model its behaviour with confidence. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • GaAs/GaAlAs p-n-p-n negative-resistance laser with low threshold current density

    Page(s): 306 - 309
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (719 KB)  

    Six-layer heterostructure p-n-p-n switching lasers with low lasing threshold current densities (2500 A cm¿2 at room temperature) and good electrical turn-on properties have been produced. The paper deals with the analysis and practical realisation of good switching characteristics and the trade-offs necessary to achieve them while maintaining low threshold-current densities. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full text access may be available. Click article title to sign in or learn about subscription options.