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Showing papers on "Semiconductor optical gain published in 1995"


Journal ArticleDOI
TL;DR: In this paper, an improved mid-wave infrared diode laser structure based on InAs•Ga1−xInxSb• InAs−Ga•Sb Type•II multiple quantum wells was proposed, which combines strong optical coupling, 2D dispersion for both electrons and holes, suppression of the Auger recombination rate and excellent electrical and optical confinement.
Abstract: We discuss an improved mid‐wave infrared diode laser structure based on InAs‐Ga1−xInxSb‐ InAs‐Ga1−xAlxSb Type‐II multiple quantum wells. The proposed design combines strong optical coupling, 2D dispersion for both electrons and holes, suppression of the Auger recombination rate, and excellent electrical and optical confinement.

412 citations


Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the phenomena occurring in semiconductor lasers due to weak external optical feedback, including mode hopping and related mode-hopping noise, linewidth narrowing and broadening, and the transition to the coherence collapse regime.
Abstract: The phenomena occurring in semiconductor lasers due to weak external optical feedback are reviewed, including mode hopping and related mode-hopping noise, linewidth narrowing and broadening, and the transition to the coherence collapse regime. Guidelines are given for designing semiconductor lasers, both edge emitters and VCSEL's, with high endurance against external optical feedback. >

317 citations


Journal ArticleDOI
TL;DR: In this article, the theoretical framework needed for studying the dynamical behaviour of semiconductor laser exposed to three kinds of optical modulation is discussed, including the effect of monochromatic injection in terms of locking and non-locking dynamics, including a thermodynamic potential for phase jumps.
Abstract: In this review we discuss the theoretical framework needed for studying the dynamical behaviour of semiconductor lasers exposed to three kinds of optical modulation. We start by a derivation of the single-mode rate-equations for the slowly varying complex electric field and the inversion, and the necessary extensions for monochromatic optical injection and normal external optical feedback. The basic operating characteristics of the solitary semiconductor laser are analysed, including light-current curves and their dependence on the spontaneous emission level, as well as the optical spectrum. The effect of monochromatic injection is discussed in terms of locking and non-locking dynamics, including a thermodynamic potential for phase jumps. The basic ingredients for studying external optical feedback are given, including a derivation of the thermodynamic potential for phase-diffusion. After an introduction on optical phase conjugation, the field rate-equation for feedback from a phase-conjugate mirror is derived.

294 citations


Proceedings ArticleDOI
17 Feb 1995
TL;DR: In this article, a good understanding of external optical feedback phenomena in semiconductor laser sources is provided, including linewidth narrowing and broadening, mode hopping phenomena and the transition to the so-called coherence-collapse regime.
Abstract: In optical fiber networks, the semiconductor laser source may be subjected to unavoidable optical feedback from fiber pigtails, fiber connectors and other components, unless expensive optical isolators are used. Therefore, a good understanding of external optical feedback phenomena in semiconductor lasers is required. This paper will review these phenomena, including linewidth narrowing and broadening, mode hopping phenomena and the transition to the so-called coherence-collapse regime. In particular, laser designs with high endurance against optical feedback will be discussed.

242 citations


Journal ArticleDOI
TL;DR: In this article, a systematic map of the various instabilities induced in a semiconductor laser subject to strong optical injection as the amount of optical injection power and frequency detuning is varied is presented.
Abstract: We have experimentally obtained and theoretically analyzed a systematic map of the various instabilities induced in a semiconductor laser subject to strong optical injection as the amount of optical injection power and frequency detuning is varied. Two distinct islands of chaos have been identified in the injection‐locked region. They are separated by regions of period one and period two solutions. Spontaneous emission noise obscures the observation of high periodic orbits.

142 citations


Book
01 Mar 1995
TL;DR: Semiconductors - crystal structure properties of semiconductors as discussed by the authors - electronic doping and carrier transport optical propetries of semiconductor devices excitonic effects and modulation semiconductor junction theory optoelectronic detectors noise and the photoreceiver the light emitting diode laser diode - static properties semiconductor lasers - dynamic properties modulation and switching devices optical communication systems list of symbols important properties of the semiconductor materials important quantum mechanics concepts bipolar transistor action optical waves in waveguides and crystals
Abstract: Semiconductors - crystal structure properties of semiconductors - electronic doping and carrier transport optical propetries of semiconductors excitonic effects and modulation semiconductor junction theory optoelectronic detectors noise and the photoreceiver the light emitting diode laser diode - static properties semiconductor lasers - dynamic properties modulation and switching devices optical communication systems list of symbols important properties of semiconductors important quantum mechanics concepts bipolar transistor action optical waves in waveguides and crystals.

128 citations


Journal ArticleDOI
TL;DR: In this article, the authors identify the various physical mechanisms in low frequency fluctuations, which occur when a semiconductor laser is subject to moderate optical feedback while operating close to its solitary laser threshold.
Abstract: We identify the various physical mechanisms in low frequency fluctuations, which occur when a semiconductor laser is subject to moderate optical feedback while operating close to its solitary laser threshold. In attempting to reach the maximum gain mode, which often is stable, the system forms short mode-locked pulses. In between pulses mode-slipping can occur, generally in the direction of maximum gain. Inevitably, the trajectory passes too close to one of the many saddle points, which will take the system back to the solitary laser state. >

120 citations


Journal ArticleDOI
TL;DR: An extended-cavity 1.5-microm semiconductor laser was frequency stabilized to saturated-absorption lines of acetylene, with long-term frequency stability of 10(-12), with a reproducibility of +/-10 kHz.
Abstract: An extended-cavity 1.5-μm semiconductor laser was frequency stabilized to saturated-absorption lines of acetylene. Its long-term frequency stability is of the order of 10−12, with a reproducibility of ±10 kHz. Using the lines of C2H2 or HCN, we could obtain such a high stability with the same laser at many wavelengths covering the 1.51 – 1.56-μm band.

119 citations


Journal ArticleDOI
TL;DR: In this paper, the longitudinal optical mode shift with temperature was measured in two vertical cavity surface-emitting laser (VCSEL) type optical resonators with different GaAs and AlAs layer structures.
Abstract: The longitudinal optical mode shift with temperature was measured in two vertical cavity surface‐emitting laser (VCSEL) type optical resonators with different GaAs and AlAs layer structures. The measurements show distinct differences in the behavior of the cavities. From the data the thermal dependencies of the indices of refraction of GaAs and AlAs for wavelengths near 1 μm were determined to be (2.67±0.07)×10−4/°C and (1.43±0.07)×10−4/°C, respectively.

109 citations


Proceedings ArticleDOI
30 May 1995
TL;DR: In this article, the frequency modulated continuous wave radar (FMCW) has been applied to optical frequencies, and several tuning principles to be used in optical FMCW are discussed.
Abstract: The principle of frequency modulated continuous wave radar (FMCW) has been applied to optical frequencies. By tuning the wavelength of a semiconductor laser with time, high resolution imaging in scattering media is possible. The spatial resolution depends mainly on the tuning range of the laser. Several tuning principles to be used in optical FMCW are discussed. As a coherent detection scheme with small bandwidth is used, low noise and high dynamic range are expected. The basic theory is outlined and experimental results are presented. Nonlinear tuning characteristics that degrade the resolution are discussed and interferometric methods enhancing system characteristics are proposed.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

105 citations


Patent
Nobuo Suzuki1, Hirayama Yuzo1
11 Sep 1995
TL;DR: A semiconductor optical waveguide device comprises a stripe-shaped semiconductor infrared waveguide, part of which is an active layer producing gain by electric current injection, and part of the semiconductor IR waveguide being an intra-band resonant absorption layer in which an IR resonant wavelength is arranged within the gain band of the active layer.
Abstract: A semiconductor optical waveguide device comprises a stripe-shaped semiconductor optical waveguide, part of the semiconductor optical waveguide being an active layer producing gain by electric current injection, and part of the semiconductor optical waveguide being an intra-band resonant absorption layer in which an intra-band absorption resonant wavelength is arranged within the gain band of the active layer, and means for injecting electric current into the active layer.

Journal ArticleDOI
TL;DR: In this article, a manybody calculation of the nonlinear optical response of bulk group-III nitrides is presented, showing that the Coulomb effects contribute significantly to the magnitude and spectral extension, as well as the temperature and carrier density dependences of the optical gain and absorption.
Abstract: A many‐body calculation of the nonlinear optical response of bulk group‐III nitrides is presented. For the example of GaN it is shown that the Coulomb effects contribute significantly to the magnitude and spectral extension, as well as the temperature and carrier density dependences of the optical gain and absorption.

Journal ArticleDOI
TL;DR: It is shown that, contrary to common wisdom, the maximum gain mode of semiconductor lasers subject to optical feedback is always stable and the minimum linewidth mode is shown to be subject to a Hopf bifurcation associated with destabilizing the relaxation oscillations.
Abstract: We show that, contrary to common wisdom, the maximum gain mode of semiconductor lasers subject to optical feedback is always stable. The minimum linewidth mode is shown to be subject to a Hopf bifurcation associated with destabilizing the relaxation oscillations. This explains the experimental observation of narrow-linewidth, single-mode diode lasers operating with high optical feedback. © 1995 The American Physical Society.

Journal ArticleDOI
TL;DR: In this paper, the authors used the Hakki-Paoli method to extract the gain and refractive index spectra of an amplified spontaneous emission spectroscopy (SSE) system.
Abstract: Amplified spontaneous emission spectroscopy is used to extract the gain and refractive index spectra systematically. We obtain the gain and differential gain spectra using the Hakki-Paoli method. The refractive index profile, the induced change in refractive index by an incremental current, and the linewidth enhancement factor are measured from the Fabry-Perot peaks and the current-induced peak shifts in the amplified spontaneous emission spectra. The measured optical gain and refractive index are then compared with our theoretical model for strained quantum-well lasers. We show that a complete theoretical model for calculating the electronic band structure, the optical constant, and the linewidth enhancement factor agrees very well with the experiment. Our approach demonstrates that amplified spontaneous emission spectroscopy can be a good diagnostic tool to characterize laser diodes, extract the optical gain and index profiles, and confirm material parameters such as the strained quantum-well band structure parameters for a semiconductor structure under carrier injection.

Journal ArticleDOI
TL;DR: An analytical solution to the problem of nondegenerate four-wave mixing in a semiconductor optical amplifier emphasizing operation with short optical pulses is described in this article, where conditions for optimum conversion efficiencies in terms of the pump input energy and the relative temporal alignment between the pulses are presented.
Abstract: An analytical solution to the problem of nondegenerate four wave mixing in a semiconductor optical amplifier emphasizing operation with short optical pulses is described. Calculated conversion efficiencies for pulses are significantly larger than for cw fields and are pulse width dependent. Conditions for optimum conversion efficiencies in terms of the pump input energy and the relative temporal alignment between the pulses are presented.

Journal ArticleDOI
TL;DR: In this paper, a dual-mode long-cavity multisection DFB laser is driven at a subharmonic of the free-running-mode beat signal frequency to produce phase-locked millimetre waves with a 3 dB linewidth of less than 10 Hz and a 3dB locking range of ~500 MHz.
Abstract: The authors demonstrate the optical generation of extremely narrow linewidth millimetre-wave signals between 40 and 60 GHz using a single-chip semiconductor laser. A dual-mode long-cavity multisection DFB semiconductor laser is driven at a subharmonic of the free-running-mode beat signal frequency to produce phase-locked millimetre waves with a 3 dB linewidth of less than 10 Hz and a 3 dB locking range of ~500 MHz.

Journal ArticleDOI
D.A.O. Davies1
TL;DR: In this article, the authors analyzed the wavelength conversion due to gain saturation in a traveling wave semiconductor laser amplifier using a small-signal model and showed that the small-Signal bandwidth of wavelength conversion is not limited simply to the carrier modulation bandwidth, but also depends on the single-pass gain of the device.
Abstract: Wavelength conversion due to gain saturation in a travelling wave semiconductor laser amplifier is analyzed using a small-signal model An analytic expression is developed showing that the small-signal bandwidth of wavelength conversion is not limited simply to the carrier modulation bandwidth, but also depends on the single-pass gain of the device >

Patent
27 Oct 1995
TL;DR: In this paper, the authors proposed a distributed feedback grating for a high power monolithic surface emitting semiconductor laser, which consists of an active region layer at which light is emitted and a complex-coupled distributed feedback GRating positioned to act upon light from the active region, and selected the grating period or the combined width of the two adjacent grating elements to be equal to a full wavelength in the semiconductor structure.
Abstract: A high power monolithic surface emitting semiconductor laser provides a single lobe far-field radiation profile which is emitted normal to the plane of a surface of the semiconductor laser structure. The semiconductor laser includes an active region layer at which light is emitted and a complex-coupled distributed feedback grating positioned to act upon light from the active region. The adjacent elements of the distributed feedback grating differ from one another in both refractive index and gain/loss. The grating period, or the combined width of the two adjacent grating elements, is selected to be equal to a full wavelength in the semiconductor structure of the light emitted from the active region. Lasing occurs in a symmetric mode, resulting in emission of light from a planar surface of the semiconductor structure perpendicular to the surface, the grating layer and the active region layer as long as the modal-gain difference between symmetric and antisymmetric modes due to optical-field overlap with the gain/loss grating overcomes the modal-gain difference based on radiation losses.

Journal ArticleDOI
TL;DR: It is shown numerically that, in some parameter regimes, spontaneous emission noise qualitatively influences the nature and statistics of the dropouts in semiconductor lasers with optical feedback.
Abstract: Semiconductor lasers with optical feedback can display sudden power-dropout events at irregular time intervals. We show numerically that, in some parameter regimes, spontaneous emission noise qualitatively influences the nature and statistics of the dropouts. Experimental measurements of the mean time between dropout events and its dependence on feedback strength agree well with analytic predictions made by Henry and Kazarinov [IEEE J. Quantum Electron. QE-22, 294 (1986)] based on the assumption that spontaneous emission noise induces these dropout events.

Journal ArticleDOI
TL;DR: Differential carrier lifetimes of semiconductor lasers are obtained directly from the device impedance measurements as discussed by the authors, which gives accurate lifetimes down to low bias currents, at which correct lifetimes are an order of magnitude higher than those obtained by a commonly used optical technique.
Abstract: Differential carrier lifetimes of semiconductor lasers are obtained directly from the device impedance measurements. This new technique gives accurate lifetimes down to low bias currents, at which correct lifetimes are an order of magnitude higher than those obtained by a commonly used optical technique. Correct lifetimes reconcile the results of early PL studies and suggest much higher carrier concentrations.

Journal ArticleDOI
TL;DR: In this paper, the influence of many-body, nonequilibrium, and cavity effects on the emission characteristics and carrier dynamics of semiconductor microcavity lasers is investigated, and nonlinear coupled equations for the carrier kinetics and the laser dynamics are derived.
Abstract: The influence of many-body, nonequilibrium, and cavity effects on the emission characteristics and carrier dynamics of semiconductor microcavity lasers is investigated. The nonlinear coupled equations for the carrier kinetics and the laser dynamics are derived. Numerical solutions for vertical cavity surface emitting lasers show that the electron-hole plasma population has strong nonequilibrium character under many realistic conditions, exhibiting plasma heating and/or kinetic hole burning. It is shown that the desired threshold reduction through increased spontaneous emission coupling is accompanied by a significant increase in the laser linewidth and deviations from the usual Schawlow-Townes line narrowing. Assuming optical excitation with femtosecond pulses, the delayed onset of laser action and the dynamical emission characteristics are computed.

Patent
16 Mar 1995
TL;DR: In this article, an oscillation polarization selective semiconductor (OPSSC) laser is used as a light source in optical communication systems, where the gain spectra generated in the active layer for induced mutually perpendicular propagation modes are selectively controlled by controlling the carrier density injected into the active layers.
Abstract: An oscillation polarization selective semiconductor laser that switches oscillation polarization modes between two different polarization modes includes a laser structure on a substrate. An active layer of the laser structure includes plural sets of quantum wells and barriers. The structure of at least one set of quantum wells and the barriers is different from the other sets so that the gain spectra generated in the active layer for induced mutually perpendicular propagation modes are selectively controlled by controlling the carrier density injected into the active layer. The oscillation polarization selective semiconductor laser may be used as a light source in optical communication systems.

Patent
Toshihiko Ouchi1, Majima Masao1, Jun Nitta1, Mishima Seiji1, Kubota Ouichi1 
09 May 1995
TL;DR: In this paper, the polarization mode of oscillation light from a semiconductor laser is switchable between two different polarization modes when a modulation current is injected into a portion of a light waveguide of the semiconductor LM.
Abstract: In a light source apparatus, the polarization mode of oscillation light from a semiconductor laser is switchable between two different polarization modes when a modulation current is injected into a portion of a light waveguide of the semiconductor laser. Light in one polarization mode and light in the other polarization mode are separately obtained from the oscillation light from the semiconductor laser. At least the light in one of the two different polarization modes is converted to an electric signal. Current injected into the semiconductor laser is controlled based on the electric signal such that a modulation state of light from the semiconductor laser is stabilized. The light in the other polarization mode, or light in one polarization mode emitted from the other emission side of the semiconductor laser may be used for optical transmission.

Journal ArticleDOI
TL;DR: In this paper, the authors show experimentally and theoretically that the bandwidth for wavelength conversion through cross-gain modulation varies approximately linearly with the length of the amplifier, and that by cascading two similar semiconductor optical amplifiers, the small-signal wavelength conversion bandwidth is doubled.
Abstract: The authors show experimentally and theoretically that the bandwidth for wavelength conversion through cross-gain modulation varies approximately linearly with the length of the amplifier. By cascading two similar semiconductor optical amplifiers, the small-signal wavelength conversion bandwidth is doubled.

Journal ArticleDOI
TL;DR: In this paper, the spatial distribution of the temperature, gain, and carrier density along the longitudinal direction of a semiconductor laser cavity is studied. But the authors do not consider the effect of temperature on the modal gain spectrum.
Abstract: We study the spatial distribution of the temperature, gain, and carrier density along the longitudinal direction of a semiconductor laser cavity. In high-power laser diodes, the use of asymmetrical facet reflectivities creates a spatially nonuniform photon intensity profile and results in inhomogeneous temperature and carrier distributions along the active stripe. These profiles are determined from direct measurements of blackbody radiation and the spontaneous emission from the laser cavity. The temperature of the active stripe is observed to be significantly higher than that of the heat sink during lasing, and the effect of temperature on the modal gain spectrum is analyzed. We demonstrate that the local carrier density and optical gain within a laser are not pinned beyond threshold. A spatially inhomogeneous gain profile is possible in laser cavities as long as the threshold condition that the averaged round-trip gain equals the total losses is maintained. A theoretical model is presented which explains the observed experimental data. >

Journal ArticleDOI
TL;DR: In this paper, the intrinsic resolution limitations of near-field photoconductivity in quantum-well heterostructures and demonstrate that the resolution depends strongly on the amount of evanescent and propagating field components in the semiconductor.
Abstract: Near-field optical microscopy and spectroscopy is emerging as a powerful tool for the investigation of semiconductor structures. Tunable excitation combined with sub-wavelength resolution is providing an unprecedented level of detail on the local optical properties of semiconductor structures. Recent near-field optical studies have addressed issues of laser diode mode profiling, minority carrier transport, near-field photocurrent response of quantum-well structures and laser diodes, imaging of local waveguide properties, and location and studies of dislocations in semiconductor thin films. We present results on the intrinsic resolution limitations of near-field photoconductivity in quantum-well heterostructures and demonstrate that the resolution depends strongly on the amount of evanescent and propagating field components in the semiconductor. Spectroscopic mode-profiling of high-power laser diode emission details the spatial dependence of multiple spectral modes. This paper presents an overview of NSOM techniques for semiconductor systems, its limitations, and present status.

Journal ArticleDOI
Takeshi Uenoyama1
TL;DR: In this article, the authors studied the optical gain in terms of the transition between a localized state and a continuous subband state with small carrier concentration, and showed that the enhanced optical gain is strongly enhanced by excitonic effects through the coupling between the two transitions.
Abstract: Excitonic effects of optical gain in quantum wells have been studied theoretically in a three-band model. Taking into account an additional localized level in the energy gap, we obtain the optical gain in terms of the transition between a localized state and a continuous subband state with small carrier concentration. Simultaneously, excitonic absorption also occurs near the band-edge transition. It is shown that the optical gain is strongly enhanced by excitonic effects through the coupling between the two transitions. This enhanced optical gain might show the realization of very-low-threshold current-laser diodes.

Journal ArticleDOI
TL;DR: In this article, a highly accurate method of measuring optical loss in individual semiconductor lasers is presented and compared with other methods, which illustrate the suitability of this technique for studying the dependence of loss on temperature and carrier density.
Abstract: A highly accurate method of measuring optical loss in individual semiconductor lasers is presented and compared with other methods. Measured loss data for 1.3 mu m semiconductor lasers are presented that illustrate the suitability of this technique for studying the dependence of loss on temperature and carrier density.

Journal ArticleDOI
TL;DR: In this article, the authors describe the dependence of four-wave mixing conversion efficiency among short optical pulses in a semiconductor optical amplifier and show a strong dependence on pulse shape and pulse overlap.
Abstract: We describe the dependence of four-wave mixing conversion efficiency among short optical pulses in a semiconductor optical amplifier We show a strong dependence on pulse shape and pulse overlap, predicted theoretically and confirmed in experiments >

Journal ArticleDOI
TL;DR: An extension of the two-level model which features asymmetric gain is introduced for semiconductor laser diodes in this article, which includes an evolution equation for the material polarization in semiconductor media obtained from the calculation of the electrical susceptibility.