Showing papers by "Amnon Yariv published in 1989"
TL;DR: In this article, the performance of the GaAs/AlGaAs superlattice as an infrared detecting material is modeled as a function of temperature for two cutoff wavelengths, namely, 8.3 and 10.0 μm.
Abstract: The performance of the GaAs/AlGaAs superlattice as an infrared detecting material is modeled as a function of temperature for two cutoff wavelengths, namely, 8.3 and 10.0 μm. The results are compared with HgCdTe, the present industry standard material for infrared systems. The limiting performance of the GaAs/AlGaAs materials system is found to be orders of magnitude below that of HgCdTe for any specific cutoff wavelength and operating temperature.
140 citations
TL;DR: Experimental results that demonstrate the formation of photorefractive gratings in KTN:Cu,V in theparaelectric phase are presented using the quadratic electro-optic effect, which allows amplitude modulation of the diffracted beam by an external electric field.
Abstract: Experimental results that demonstrate the formation of photorefractive gratings in KTN:Cu,V in the paraelectric phase are presented. These gratings are formed using the quadratic electro-optic effect, which allows amplitude modulation of the diffracted beam by an external electric field. High diffraction efficiencies of over 50% in a 3-mm thick sample and amplitude modulation of the diffracted beam by an external field at frequencies of up to 20 kHz were observed.
74 citations
TL;DR: In this article, a new technique for determining carrier diffusion length by cathodoluminescence measurements is presented, which is extremely accurate and can be applied to a variety of structures.
Abstract: A new technique for determining carrier diffusion lengths by cathodoluminescence measurements is presented. The technique is extremely accurate and can be applied to a variety of structures. Ambipolar diffusion lengths are determined for GaAs quantum well material, bulk GaAs, Al0.21Ga0.79As, and Al0.37Ga0.63As. A large increase in the diffusion length is found for Al0.37Ga0.63As and is attributed to an order of magnitude increase in lifetime.
66 citations
TL;DR: In this article, low threshold current was obtained for InGaAs/AlGaAs single quantum well lasers grown by molecular beam epitaxy, and the best device showed 0.9 mA threshold current (L=225 µm).
Abstract: We report on low threshold current strained InGaAs/AlGaAs single quantum well lasers grown by molecular beam epitaxy. Broad-area threshold current densities of 114 A/cm2 at 990 nm were measured for 1540-µm-long lasers. Threshold currents of 2.4 mA at 950 nm were obtained for an uncoated buried-heterostructure device with a 2-µm-wide stripe and 425-µm-long cavity. With reflective coatings the best device showed 0.9 mA threshold current (L=225 µm). Preliminary modulation measurements show bandwidths up to 5.5 GHz limited by the detector response.
52 citations
TL;DR: In this article, the effects of fabricational variations on the gain spectra of quantum wires are calculated within the limits of first-order perturbation theory, and upper limits on the size of quantum wells, quantum wires, and quantum boxes are also discussed.
Abstract: The effects of fabricational variations on the gain spectra of quantum wires are calculated within the limits of first-order perturbation theory. Gain spectra and density of states for 50-AA-radius and 150-AA-radius cylindrical quantum wires are calculated and plotted for several different fabrication tolerances. The wave functions for a finite, cylindrical potential are calculated and a quasicritical radius, below which the carriers are weakly confined by the potential, is established. This sets a lower limit on quantum wire size. Upper limits on the size of quantum wells, quantum wires, and quantum boxes are also discussed. The threshold current and differential gain of quantum-wire lasers and quantum wire array lasers are calculated. These calculations indicate a possible reduction in threshold current of one to two orders of magnitude as compared to the best quantum-well lasers. >
46 citations
TL;DR: In this paper, the ambipolar diffusion length and carrier lifetime are measured in AlxGa1−xAs for several mole fractions in the interval 0
Abstract: The ambipolar diffusion length and carrier lifetime are measured in AlxGa1−xAs for several mole fractions in the interval 0
46 citations
TL;DR: In this article, the resonator loss is optimized to invoke lasing from both the first and second quantized states of the single quantum well active region (SLER) of a semiconductor laser in a grating-coupled external cavity.
Abstract: Uncoated, Fabry-Perot (AlGa)As semiconductor lasers are tuned over 105nm in a grating-coupled external cavity. Broadband tunability is achieved by optimising the resonator loss so as to invoke lasing from both the first and second quantised states of the single quantum well active region.
37 citations
TL;DR: In this paper, single quantum well AlGaAs/GaAs graded-index separate-confinement heterostructure lasers have been fabricated using MeV oxygen ion implantation plus optimized subsequent thermal annealing.
Abstract: Single quantum well AlGaAs/GaAs graded-index separate-confinement heterostructure lasers have been fabricated using MeV oxygen ion implantation plus optimized subsequent thermal annealing. A high differential quantum efficiency of 85% has been obtained in a 360-µm-long and 10-µm-wide stripe geometry device. The results have also demonstrated that excellent electrical isolation (breakdown voltage of over 30 V) and low threshold currents (22 mA) can be obtained with MeV oxygen ion isolation. It is suggested that oxygen ion implantation induced selective carrier compensation and compositional disordering in the quantum well region as well as radiation-induced lattice disordering in AlxGa1–xAs/GaAs may be mostly responsible for the buried layer modification in this fabrication process.
35 citations
TL;DR: In this paper, the gain requirement for a grating-tuned external cavity configuration is examined and applied to a semiconductor quantum well laser with an optimized length of gain region.
Abstract: Quantum well lasers are shown to exhibit flattened broadband gain spectra at a particular pumping condition. The gain requirement for a grating-tuned external cavity configuration is examined and applied to a semiconductor quantum well laser with an optimized length of gain region. The predicted very broadband tunability of quantum well lasers is confirmed experimentally by grating-tuning of uncoated lasers over 85 nm, with single longitudinal mode output power exceeding 200 mW.
30 citations
TL;DR: In this paper, the aluminum concentration in the epilayers is dependent on the facet orientation, changing by as much as 35% from the value in unpatterned areas, and the transition in aluminum concentration at a boundary between two facets is observed to be very abrupt.
Abstract: Cathodoluminescence scanning electron microscopy is used to study AlxGa1−x As epilayers grown on a nonplanar substrate by molecular beam epitaxy. Grooves parallel to the [011] direction were etched in an undoped GaAs substrate. Growth on such grooves proceeds on particular facet planes. We find that the aluminum concentration in the epilayers is dependent on the facet orientation, changing by as much as 35% from the value in the unpatterned areas. The transition in the aluminum concentration at a boundary between two facets is observed to be very abrupt.
28 citations
02 Mar 1989-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this article, the formation of buried high-resistivity layers in InP single crystals by MeV ion implantation was studied, and it was found that the implantation of MeV nitrogen ions plus subsequent thermal annealing can generate a deep burried layer with resistivity up to about 10^6 Ω cm in n-type InP crystals.
Abstract: We have studied the formation of buried high-resistivity layers in InP single crystals by MeV ion implantation. It was found that the implantation of MeV nitrogen ions plus subsequent thermal annealing can generate a deep burried layer with resistivity up to about 10^6 Ω cm in n-type InP crystals. This layer has exhibited implant dose dependence, high thermal stability and reproducibility over a dose range of 5 × 10^(14) − 1 × 10^(16) cm^(−2). The mechanism of insulating layer generation by implantation, based on cross sectional transmission electron microscopy (XTEM) and I–V curve measurements, as well as the application of this technique in device fabrication, will be discussed.
TL;DR: In this article, the phase shift and cross talk of conjugate waves from a self-pumped phase-conjugate mirror are investigated by a phenomenological model based on the four-wave mixing process and measured as a function of a uniform phase change of a wave incident upon the mirror.
TL;DR: In this paper, the photorefractive two-beam coupling constant and response time of two Cr-doped strontium barium niobate crystals with different dopant concentrations were investigated.
Abstract: We present experimental results on the photorefractive two-beam coupling constant and response time of two Cr-doped strontium barium niobate crystals with different dopant concentrations. Both showed significantly faster response times over Ce-doped SBN:60, but with corresponding decreases in their coupling constants.
TL;DR: The theoretical and experimental results of photorefractive two-beam coupling in Cr-doped strontium barium niobate are presented, using thermal excitation (i.e., dark conductivity) to model the experimentally observed temperature-dependent behavior of the two- beam coupling constant and response time.
Abstract: We present the theoretical and experimental results of photorefractive two-beam coupling in Cr-doped strontium barium niobate:60, using thermal excitation (i.e., dark conductivity) to model the experimentally observed temperature-dependent behavior of the two-beam coupling constant and response time.
TL;DR: In this article, an active chirped-corrugation waveguide filter (ACF) is proposed for monolithic broadband tuning of semiconductor lasers, based on spatially selective gain pumping.
Abstract: A novel tunable semiconductor waveguide reflection filter is proposed and analyzed. The filter is based on spatially selective gain pumping of a chirped‐corrugation waveguide. This active chirped‐corrugation waveguide filter (ACF) is considered for monolithic broadband tuning of semiconductor lasers.
TL;DR: In this paper, the phase-conjugation process as a function of input-beam launching conditions is discussed and several new applications of the scheme which involve correction of non-reciprocal polarization distortions, correction of lossy amplitude distortions, phaseconjugate multimode fiber-optic interferometers and gyros, temporal data channeling between beams, and all-optical beam thresholding are described.
Abstract: Recent theoretical and experimental studies of polarization and spatial information recovery by modal dispersal and phase-conjugation are discussed. The fidelity of this phase-conjugation process as a function of input-beam launching conditions is discussed. Several new applications of the scheme which involve correction of nonreciprocal polarization distortions, correction of lossy amplitude distortions, phase-conjugate multimode fiber-optic interferometers and gyros, temporal data channeling between beams, and all-optical beam thresholding are described. >
01 May 1989
TL;DR: In this article, the gain requirement for a grating-tuned external cavity configuration is examined and is applied to a semiconductor quantum-well laser with an optimized length of gain region.
Abstract: Semiconductor injection lasers are known to be tunable over a range of order kB T. Quantum-well lasers, in particular, are shown to exhibit flattened, broadband gain spectra at a particular pumping condition. The gain requirement for a grating-tuned external cavity configuration is examined and is applied to a semiconductor quantum-well laser with an optimized length of gain region. The coupled-cavity formalism is employed to examine the conditions for continuous tuning. The possible tuning range of double-heterostructure lasers is compared to that of quantum-well lasers. The predicted broadband tunability of quantum-well lasers is confirmed experimentally by grating-tuning of uncoated lasers exceeding 120 nm, with single, longitudinal mode output power exceeding 300 mW.
TL;DR: In this article, the authors present a novel approach to photoconductive sampling with a resolution which is virtually independent of the carrier lifetime and is governed solely by the circuit-limited gap charging time.
Abstract: We present a novel approach to photoconductive sampling with a resolution which is virtually independent of the carrier lifetime and is governed solely by the circuit‐limited gap charging time. Using photoconductors with a carrier lifetime of 150 ps, accurate measurement of a 65‐ps‐wide electrical signal is demonstrated and the actual resolution is believed to be 10 ps.
03 Dec 1989
TL;DR: In this article, a novel technique for determining carrier diffusion length in direct gap semiconductors by cathodoluminescence measurement is presented, which is attributed to an order-of-magnitude increase in lifetime > 038.
Abstract: A novel technique for determining carrier diffusion lengths in direct gap semiconductors by cathodoluminescence measurement is presented Ambipolar diffusion lengths are determined for GaAs quantum-well material, bulk GaAs, and Al/sub x/Ga/sub 1-x/As with x up to 038 A large increase in the diffusion length is found as x approaches 038 and is attributed to an order-of-magnitude increase in lifetime >
TL;DR: In this paper, a buried crescent InGaAsP/InP laser with a double active layer was fabricated and a theoretical model using a rate equation approach showed good agreement with the experimental results.
Abstract: A buried crescent InGaAsP/InP laser with a double active layer was fabricated. The laser showed very high characteristic temperature T0 and highly nonlinear light versus current characteristics. A theoretical model using a rate equation approach showed good agreement with the experimental results.
Proceedings Article•
24 Apr 1989
22 Jun 1989
TL;DR: In this article, the effects of fabricational variations on the gain spectra of quantum wires are calculated within the limits of first-order perturbation theory, and the threshold current and differential gain of quantum wire lasers and quantum wire array lasers are calculated.
Abstract: The effects of fabricational variations on the gain spectra of quantum wires are calculated within the limits of first order perturbation theory. Gain spectra and density of states for 50A radius and 150A radius cylindrical quantum wires are calculated and plotted for several different fabrication tolerances. The wave functions for a finite, cylindrical potential are calculated and a quasi-critical radius, below which the carriers are weakly confined by the potential, is established. This sets a lower limit on quantum wire size. Upper limits on the size of quantum wells, quantum wires, and quantum boxes are also discussed. The threshold current and differential gain of quantum wire lasers and quantum wire array lasers are calculated. These calculations indicate a possible reduction in threshold current of one to two orders of magnitude as compared to the best quantum well lasers to date.