Showing papers on "Semiconductor optical gain published in 2006"
TL;DR: In this paper, a surface plasmon device composed of a resonant optical antenna integrated on the facet of a commercial diode laser, termed a Plasmonic Laser antenna, was demonstrated.
Abstract: The authors have demonstrated a surface plasmon device composed of a resonant optical antenna integrated on the facet of a commercial diode laser, termed a plasmonic laser antenna. This device generates enhanced and spatially confined optical near fields. Spot sizes of a few tens of nanometers have been measured at a wavelength ∼0.8μm. This device can be implemented in a wide variety of semiconductor lasers emitting in spectral regions ranging from the visible to the far infrared, including quantum cascade lasers. It is potentially useful in many applications including near-field optical microscopes, optical data storage, and heat-assisted magnetic recording.
414 citations
TL;DR: This work developed the procedures to produce a smooth, low-scattering-loss film inside the capillary, resulting in a whispering gallery mode laser with a well-defined threshold, and represents the first report of an infrared laser made using solution processing.
Abstract: Sources of coherent, monochromatic short-wavelength infrared (1-2 μm) light are essential in telecommunications, biomedical diagnosis, and optical sensing. Today’s semiconductor lasers are made by epitaxial growth on a lattice-matched single-crystal substrate. This strategy is incompatible with direct growth on silicon. Colloidal quantum dots synthesized in solution can, in contrast, be coated onto any surface. Here we show a 1.53 μm laser fabricated using a remarkably simple process: dipping a glass capillary into a colloidal suspension of semiconductor quantum dots. We developed the procedures to produce a smooth, low-scattering-loss film inside the capillary, resulting in a whispering gallery mode laser with a well-defined threshold. While there exist three prior reports of optical gain in infrared-emitting colloidal quantum dots [1, 2, 3], this work represents the first report of an infrared laser made using solution processing. We also report dλmax/dT, the temperature-sensitivity of lasing wavelength, of 0.03 nm/K, the lowest ever reported in a colloidal quantum dot system and 10 times lower than in traditional semiconductor quantum wells.
192 citations
TL;DR: The vertical-external-cavity surface-emitting (VESEM) laser as mentioned in this paper is a diode-pumped solid-state laser with a semiconductor quantum well gain medium.
182 citations
TL;DR: In this paper, the authors reported near-infrared lasing in the telecommunications band in gallium antimonide semiconductor subwavelength wires for future photonic integrated circuits for telecommunications applications.
Abstract: We report near-infrared lasing in the telecommunications band in gallium antimonide semiconductor subwavelength wires. Our results open the possibility of the use of semiconductor subwavelength-wire lasers in future photonic integrated circuits for telecommunications applications.
148 citations
TL;DR: In this article, a theoretical and experimental study of the optical gain, refractive index change, and linewidth enhancement factor (LEF) of a p-doped quantum-dot (QD) laser is reported.
Abstract: A theoretical and experimental study of the optical gain, refractive index change, and linewidth enhancement factor (LEF) of a p-doped quantum-dot (QD) laser is reported These parameters are measured by injecting an external pump, which induces cross-gain and cross-phase modulation A comprehensive theoretical model for the optical gain and refractive index change of InAs QD lasers is introduced with the quasi-equilibrium approximation of carrier distribution We use the Gaussian lineshape function for gain change and the confluent hypergeometric function of the first kind for refractive index change, which satisfies the Kramers-Kronig relation We match the experimental data with the theoretical results when the thermal effect is isolated by an additional pulsed current measurement We also calculate theoretically the optical gain, refractive index change, and LEF of an undoped QD laser of the same structure except the absence of p-type doping We show that the differential gain and LEF of the p-doped QD laser are improved compared with those of the undoped QD laser due to the reduced transparency carrier density
147 citations
TL;DR: In this paper, gain and lasing processes in individual self-assembled organic nanofibers grown on mica substrates were studied and it was shown that the gain-induced response of the nanofiber response depends sensitively on the fiber structure.
Abstract: We study gain and lasing processes in individual self-assembled organic nanofibers grown on mica substrates. The gain-induced response of the nanofibers is found to depend sensitively on the fiber structure. In homogeneous fibers where no coherent optical feedback is present, high net optical gain (of up to 103cm−1) results in spectral narrowing at the material gain peaks. In the case of strong optical feedback, which occurs in long nanofibers with randomly distributed scattering centers, gain is in turn responsible for low-threshold coherent random laser action.
124 citations
Patent•
27 Apr 2006
TL;DR: In this paper, the authors proposed an optical path difference between the split beams to reduce optical interference, which is defined as a length equivalent to the pulse width of the laser beam or more and less than the length of the pulse repetition interval.
Abstract: It is an object to achieve continuous crystal growth without optical interference using a compact laser irradiation apparatus. A megahertz laser beam is split and combined to crystallize a semiconductor film. At this point of time, an optical path difference is provided between the split beams to reduce optical interference. The optical path difference is set to have a length equivalent to the pulse width of the megahertz laser beam or more and less than a length equivalent to the pulse repetition interval; thus, optical interference can be suppressed with a very short optical path difference. Therefore, laser beams can be applied continuously and efficiently without energy deterioration.
107 citations
TL;DR: In this paper, the authors demonstrate the existence and control of cavity solitons in externally driven vertical-cavity semiconductor lasers above a threshold using a model including material polarization dynamics.
Abstract: We experimentally demonstrate the existence and the control of cavity solitons in externally driven vertical-cavity semiconductor lasers above threshold. A model including material polarization dynamics is used to predict and confirm the experimental findings.
107 citations
TL;DR: All-optical noninvasive control of a multisection semiconductor laser by means of time-delayed feedback from an external Fabry-Perot cavity is realized experimentally and phase-dependent feedback is used to demonstrate stabilization of the continuous-wave laser output and non invasive suppression of intensity pulsations.
Abstract: All-optical noninvasive control of a multisection semiconductor laser by means of time-delayed feedback from an external Fabry-Perot cavity is realized experimentally. A theoretical analysis, in both a generic model as well as a device-specific simulation, points out the role of the optical phase. Using phase-dependent feedback we demonstrate stabilization of the continuous-wave laser output and noninvasive suppression of intensity pulsations.
101 citations
TL;DR: Design criteria to optimize the delay-bandwidth product of the optical delay in semiconductor optical amplifiers and absorbers are obtained and found to agree well with the experimental data.
Abstract: We investigate variable optical delay of a microwave modulated optical beam in semiconductor optical amplifier/absorber waveguides with population oscillation (PO) and nearly degenerate four-wave-mixing (NDFWM) effects. An optical delay variable between 0 and 160 ps with a 1.0 GHz bandwidth is achieved in an InGaAsP/InP semiconductor optical amplifier (SOA) and shown to be electrically and optically controllable. An analytical model of optical delay is developed and found to agree well with the experimental data. Based on this model, we obtain design criteria to optimize the delay-bandwidth product of the optical delay in semiconductor optical amplifiers and absorbers.
83 citations
TL;DR: In this paper, the authors demonstrate room temperature optically and electrically controllable group delay using population oscillation in a quantum-dot (QD) optical amplifier (SOA).
Abstract: We demonstrate room temperature optically and electrically controllable group delay using population oscillation in a quantum-dot (QD) semiconductor optical amplifier (SOA). A reduction of the group index up to 10% with a bandwidth of 13 GHz is achieved under different configurations of injection current and optical pump intensity. Our theoretical results based on population pulsation agree well with experimental data. We extract the linewidth enhancement factor and effective carrier diffusion coefficient of the QD SOA. We also observe slow light when the injection current is increased.
TL;DR: In this paper, a microscopic theory is used to analyze optical gain in InGaN∕GaN quantum wells (QW), and experimental data are obtained from Hakki-Paoli measurements on edge-emitting lasers for different carrier densities.
Abstract: A microscopic theory is used to analyze optical gain in InGaN∕GaN quantum wells (QW). Experimental data are obtained from Hakki–Paoli measurements on edge-emitting lasers for different carrier densities. The simulations are based on the solution of the quantum kinetic Maxwell–Bloch equations, including many-body effects and a self-consistent treatment of piezoelectric fields. The results confirm the validity of a QW gain description for this material system with a substantial inhomogeneous broadening due to structural variation. They also give an estimate of the nonradiative recombination rate.
TL;DR: An all-optical AND gate based on optically induced nonlinear polarization rotation of a probe light in a bulk semiconductor optical amplifier is realized at a bit rate of 2.5Gbit/s and the extinction ratio is improved by 8dB compared with previously published work.
Abstract: An all-optical AND gate based on optically induced nonlinear polarization rotation of a probe light in a bulk semiconductor optical amplifier is realized at a bit rate of 2.5Gbit/s. By operating the AND gate in an up and inverted wavelength conversion scheme, the extinction ratio is improved by 8dB compared with previously published work.
TL;DR: In this article, a WDM-PON system which uses the laser light injected reflective semiconductor optical amplifier (R-SOA) as the optical transmitter is proposed, where the optical carrier consists of a pair of the perpendicularly polarized laser lights to avoid the polarization dependence of R-SOAs.
TL;DR: In this paper, the collector I-V characteristics of a transistor laser were analyzed and a decrease in the common-emitter gain (β≡ΔIC∕ΔIB) was shown to be related to carrier recombination.
Abstract: Data are presented showing significant structure in the collector I-V characteristics of a transistor laser, a decrease (“compression”) in the common-emitter gain (β≡ΔIC∕ΔIB), that can be mapped in some detail and related to quantum well (QW) carrier recombination. The change in gain (β) and laser wavelength corresponding to stimulated recombination (stimulated emission) on QW transitions, which is compared with operation in spontaneous recombination (cavity Q spoiled), is used with conventional transistor charge analysis to reveal the dynamic properties of the transistor laser.
TL;DR: In this paper, the authors investigated the recovery dynamics of optical amplifiers and explained why the ultrafast component of the gain recovery is largely absent in the phase response, which has important implications for optical signal processing.
Abstract: An investigation of the recovery dynamics of semiconductor optical amplifiers (SOAs) explains why the ultrafast component of the gain recovery is largely absent in the phase response. The time-resolved gain and phase dynamics of a bulk GaInAs SOA are measured using a pump-probe technique and differences between the gain and phase recoveries are highlighted and explained using Kramers-Kronig analysis. These have important implications for optical signal processing.
TL;DR: In this paper, the behavior of period-one oscillations in optically injected semiconductor lasers as a function of linewidth enhancement factor is investigated and the occurrence of the dynamics is favored by large values of the factor.
Abstract: The behavior of period-one oscillations in optically injected semiconductor lasers as a function of linewidth enhancement factor is investigated. The occurrence of the dynamics is favored by large values of the factor. The dependence of the spectral features of the dynamics on the factor suggests a strong relation between the emergence of the dynamics and the preferred cavity resonance under external perturbation.
TL;DR: Optical gain and lasing properties of ZnO∕ZnMgO multiple quantum wells with and without separate optical confinement in the temperature range from 5to290K were investigated in this article.
Abstract: Optical gain and lasing properties of ZnO∕ZnMgO multiple quantum wells with and without separate optical confinement are investigated in the temperature range from 5to290K. The data signify that localized states are crucially involved in the laser action up to room temperature. The lasing threshold increases by about one order of magnitude and reaches 140kW∕cm2 at 290K. The room temperature material gain is in the 103cm−1 range.
TL;DR: In this article, the gain of p-doped and intrinsic InAs∕GaAs quantum dot lasers is studied at room temperature and at 350K, and it is shown that, due to the wider nonthermal distribution of carriers amongst the dots at T=293K, the peak net gain of the p-Doped lasers is actually less at low injection than that of the undoped devices.
Abstract: The gain of p-doped and intrinsic InAs∕GaAs quantum dot lasers is studied at room temperature and at 350K. Our results show that, although one would theoretically expect a higher gain for a fixed carrier density in p-doped devices, due to the wider nonthermal distribution of carriers amongst the dots at T=293K, the peak net gain of the p-doped lasers is actually less at low injection than that of the undoped devices. However, at higher current densities, p doping reduces the effect of gain saturation and therefore allows ground-state lasing in shorter cavities and at higher temperatures.
TL;DR: In this article, the authors studied the power and spectral characteristics of semiconductor laser at high excitation levels (up to 100 kA/cm2) in pulsed lasing mode (100 ns, 10 kHz).
Abstract: It is shown that the reason why the maximum attainable optical power in semiconductor lasers is limited is the finite time of carrier energy relaxation via scattering by nonequilibrium optical phonons in the quantum-well active region. The power and spectral characteristics of semiconductor lasers are studied experimentally at high excitation levels (up to 100 kA/cm2) in pulsed lasing mode (100 ns, 10 kHz). As the drive current increases, the maximum intensity of stimulated emission tends to a constant value (“saturates”), and the emitted power increases owing to extension of the spectrum to shorter wavelengths. The intensity saturation is due to limitation of the rate of stimulated recombination, caused by a finite time of the electron energy relaxation via scattering by polar optical phonons. It is found that the broadening of the stimulated emission spectrum is related to an increase in carrier concentration in the active region, which enhances the escape of electrons into the waveguide layers. As the drive current increases, the carrier concentration in the waveguide reaches its threshold value and there appears an effective channel of current leakage from the active region. The experiment shows that the appearance of a band of waveguide lasing correlates with a sharp drop in the differential quantum efficiency of a semiconductor laser.
TL;DR: In this paper, the InP-based quantum dash (QDash) layer structures were used to realize ultrawide-gain bandwidth lasers for applications in the 1.55μm telecommunication range.
Abstract: The excellent wavelength tuning properties of InP-based quantum dash (QDash) layer structures were used to realize ultrawide-gain bandwidth lasers for applications in the 1.55μm telecommunication range. To expand the attainable gain bandwidth six QDash layers with three different emission wavelengths were combined in a laser structure. Broad area laser evaluation reveals good device performance. Within the optical telecommunication band at 1.55μm a gain bandwidth of more than 300nm could be experimentally confirmed, which is in good quantitative agreement with theoretical predictions by taking into account an inhomogeneous carrier distribution between the different dash layers.
TL;DR: In this paper, a compact solid state optical amplifier based on conjugated polymer poly[2methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] has been demonstrated.
Abstract: A compact, solid state optical amplifier based on the conjugated polymer poly[2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] has been demonstrated. The amplifier was optically pumped. Gratings were used to couple the signal into and out of the film. The transmitted signal was amplified over 100 times in a 1mm long waveguide giving 21dB gain at 630nm. A gain of >13dB was observed at 615 and 650nm giving a gain bandwidth of >26THz. The gain dynamics at pump densities below 5μJ∕cm2 are described by an exciton-exciton annihilation model. At higher pump intensities, amplified spontaneous emission and photoinduced losses become significant.
TL;DR: In this article, a single-emitter multiple-input transistor laser has been realized and demonstrated in signal mixing, yielding in the stimulated-recombination region near laser threshold frequency conversion with simultaneously an electrical and optical output signal.
Abstract: A single-emitter multiple-input transistor laser has been realized and demonstrated in signal mixing, yielding in the stimulated-recombination region near laser threshold frequency conversion with simultaneously an electrical and optical output signal. In the unique nonlinear region of compression of the transistor I-V characteristics (β≡ΔIC∕ΔIB, βspon>βstim), input signals f1=2GHz and f2=2.1GHz are converted into mf1±nf2 ranging from 0.1to8.4GHz. Stimulated emission (enhanced recombination) changes the transistor into a special form of nonlinear element, a special form of electronic processor or “switch.”
TL;DR: In this article, the authors provide an update on the further development of optically pumped semiconductor lasers based on the InAs∕InGaSb ∕InAs type-II quantum wells, and show increased power generation and inherent flexibility to produce devices that can emit at any wavelength in the ∼2.4μm to ∼9.3μm range with consistently high photon-to-photon conversion rates.
Abstract: We provide an update on the further development of optically pumped semiconductor lasers based on the InAs∕InGaSb∕InAs type-II quantum wells. We show increased power generation, as well as the inherent flexibility to produce devices that can emit at any wavelength in the ∼2.4μm to ∼9.3μm range with consistently high photon-to-photon conversion rates.
09 Feb 2006
TL;DR: In this article, it is shown that fully microscopic many-body models are required for a correct description of the dominant carrier loss processes in semiconductor lasers, spontaneous emission and Auger recombination, and that they are able to quantitatively predict these losses.
Abstract: It is demonstrated that fully microscopic many-body models are required for a correct description of the dominant carrier loss processes in semiconductor lasers, spontaneous emission and Auger recombination, and that they are able to quantitatively predict these losses. The density dependence of the losses assumed in semi-empirical approaches, J=AN+BN2+CN3, is shown to break down already near transparency. For the spontaneous emission it is shown to decrease from quadratic to linear (BN), Auger rates are shown to
increase only quadratically (CN2) or even less.
TL;DR: In this paper, the authors demonstrate within a metrology experiment the applicability of a recently proposed temporally incoherent semiconductor laser source which relies on nonlinear dynamics and realized spectrally broadband emission with an output power of 110mW and a coherence length of only 120μm.
Abstract: The authors demonstrate within a metrology experiment the applicability of a recently proposed temporally incoherent semiconductor laser source which relies on nonlinear dynamics. The realized spectrally broadband emission with an output power of 110mW and a coherence length of only 120μm is used in a rainbow refractometry experiment for sizing of liquid droplets, representing an important problem in industrial processes. The observed emission characteristics are attractive for implementation of modern imaging and metrology techniques which are based on the properties of well-directed, temporally incoherent light.
TL;DR: In this article, the authors studied the optical gain behavior of semiconductor quantum dots within a quantum-kinetic theory, with carrier-carrier and carrier-phonon scattering treated using renormalized quasiparticle states.
Abstract: Optical gain behavior of semiconductor quantum dots is studied within a quantum-kinetic theory, with carrier-carrier and carrier-phonon scattering treated using renormalized quasiparticle states. For inhomogeneously broadened samples, we found the excitation dependence of gain to be basically similar to quantum-well and bulk systems. However, for a high quality sample, our theory predicts the possibility of a decreasing peak gain with increasing carrier density. This anomaly can be attributed to the delicate balance between state filling and dephasing.
TL;DR: In this paper, semianalytic estimates for the Q-switching instability boundary of the continuous-wave (cw) mode-locking regime domain for a ring-cavity semiconductor laser were provided.
Abstract: We suggest semianalytic estimates for the Q-switching instability boundary of the continuous-wave (cw) mode-locking regime domain for a ring-cavity semiconductor laser. We use a differential delay laser model that allows us to assume large gain and loss in the cavity, which is a typical situation for this class of lasers. The Q-switching instability boundary is obtained as a Neimark-Sacker bifurcation curve of a map describing the transformation of pulse parameters after a round trip in the cavity. We study the dependence of this boundary on laser parameters and show that our theoretical results are in qualitative agreement with the experimental data obtained with a passively mode-locked monolithic semiconductor laser.
TL;DR: The properties of GaAs based quantum dot semiconductor lasers emitting near 1310 nm are analysed and the line-width enhancement factor is shown to depend strongly on device temperature, ranging from 1.5 at 20 degrees C to 5 at 50 degrees C.
Abstract: We analyse the properties of GaAs based quantum dot semiconductor lasers emitting near 1310 nm. The line-width enhancement factor is shown to depend strongly on device temperature, ranging from 1.5 at 20 degrees C to 5 at 50 degrees C. With optical feedback from a distant reflector, devices remained stable at 20 degrees C but displayed a range of instabilities at 50 degrees C, including irregular power drop--outs and periodic pulsations, before entering a chaotic regime. Such dynamical features are unique to quantum dot lasers -- quantum well lasers are significantly more unstable under optical feedback making such a clear route to chaos difficult to observe.
TL;DR: In this paper, the authors numerically investigate the detailed characteristics of chaos synchronization in semiconductor lasers subject to polarization-rotated optical feedback and find two types of synchronization with different time-lags.
Abstract: We numerically investigate the detailed characteristics of chaos synchronization in semiconductor lasers subject to polarization-rotated optical feedback. The emission of the dominant TE mode of a drive laser is rotated 90 deg and fed back to the laser with time delay. The polarization-rotated TE mode is also injected with time delay into the TM mode of a second laser. Two types of synchronization with different time-lags are found, as in the case for synchronization in semiconductor lasers with nonrotated optical feedback. However, a significant difference to the nonrotated optical feedback case is that neither of the two types of synchronization requires matching of optical carrier frequency between the two lasers.