Showing papers by "Amnon Yariv published in 1974"
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01 Aug 1974
TL;DR: In this article, the theory of dielectric waveguide modes is reviewed, and the topics of directional coupling, input-output coupling, modulation, and distributed feedback laser sources are treated on the basis of coupled-mode theory.
Abstract: Phenomena associated with the propagation and manipulation of light in thin-film dielectric waveguides are presently the object of considerable research effort, directed toward possible applications in communications and information processing. The theory of dielectric waveguide modes is reviewed, and the topics of directional coupling, input-output coupling, modulation, and distributed feedback laser sources are treated on the basis of coupled-mode theory. A summary of experimental results for each of the guided-wave optical phenomena covered by the theory is also presented.
244 citations
TL;DR: In this paper, the authors reported laser oscillation at 80 −100°K in electrically pumped GaAs−Ga1−xAlxAs double-heterostructure distributed feedback diode lasers.
Abstract: We report laser oscillation at 80–100°K in electrically pumped GaAs–Ga1−xAlxAs double‐heterostructure distributed‐feedback diode lasers. The feedback for laser oscillation was provided by a corrugated interface between the active GaAs layer and the p‐Ga1−xAlxAs layer. The lowest threshold current density was 2.5 kA/cm2 in pulsed operation. The wavelength of laser emission was 8112 A at 82°K with a half‐width of less than 0.3 A. The temperature dependence of the laser wavelength was found to be smaller than that of the conventional Fabry‐Perot laser.
79 citations
TL;DR: Two-channel imbedded directional couplers were fabricated with proton implantation, yielding complete light transfer in 2 mm, and a method of directional coupling was demonstrated.
Abstract: Two-channel imbedded directional couplers were fabricated with proton implantation, yielding complete light transfer in 2 mm. Ridged channel guides were fabricated by ion-micromachining epitaxial layers, and a method of directional coupling was demonstrated.
72 citations
TL;DR: In this article, the basic differential equation governing laser noise is derived from classical and quantum mechanical considerations, and its linearized Van Der Pol form is used to derive the frequency, field, and intensity fluctuation spectra.
Abstract: The basic differential equation governing laser noise is derived from classical and quantum mechanical considerations. Its linearized Van Der Pol form is used to derive the frequency, field, and intensity fluctuation spectra.
32 citations
TL;DR: The presence of gain in a periodic optical medium causes a fundamental change of the propagation behavior near the Bragg regime as mentioned in this paper, where the usual evanescent decay turns into exponential amplification.
28 citations
TL;DR: In this article, expressions for the coupling coefficients characterizing Bragg x-ray scattering in single crystals were derived, which were used to obtain the threshold gain of a new type of x•ray distributed feedback laser.
Abstract: Expressions for the coupling coefficients characterizing Bragg x‐ray scattering in single crystals are derived. These are used to obtain the threshold gain of a new type of x‐ray distributed‐feedback laser.
24 citations
TL;DR: In this paper, the liquid phase epitaxy of GaAlAs was performed on GaAs fine surface corrugations, and the growth conditions were optimized to achieve the desired performance with only minimal meltback.
Abstract: Liquid phase epitaxy of GaAlAs was performed on GaAs fine surface corrugations. By optimizing the growth conditions, GaAlAs layers were grown successfully with only minimal meltback.
20 citations
TL;DR: In this article, the authors used the nonlinear absorption of intense laser light to obtain information about the times required for spectral cross relaxation (T3) and collisional dephasing (T2) in organic dye solutions.
Abstract: The nonlinear absorption of intense laser light is used to obtain information about the times required for spectral cross relaxation (T3) and collisional dephasing (T2) in organic-dye solutions. The steady-state transmission experiment of Huff and DeShazer indicates that T2 is in the range 0.1-1 psec for cryptocyanine-methanol, while T3 is in the range 1-10 psec. For DDI-glycerin (1, 1′-diethyl-2, 2′-dicarbocyanine-iodide-glycerin), measurements of ultrashort-pulse transmission as a function of incident energy and optical polarization suggest a value T2=0.4±0.2 psec for that system. These results are based on a new set of rate equations for absorption by inhomogeneously broadened organic-dye solutions. The equations display the effects of spectral cross relaxation and are not limited to light intensities less than those at which coherent interaction effects become important. For the case of ultrashort incident pulses, the equations are extended to account for excited-state absorption, the dependence of absorption on optical polarization, and the existence of a multiplicity of interacting excited states.
14 citations
TL;DR: In this article, a monolithic structure for solid-state traveling-wave amplifiers is proposed, which promises efficient interaction between a drifting charge carrier stream and a slow electromagnetic wave component.
Abstract: A new monolithic structure for solid‐state traveling‐wave amplifiers is proposed, which promises efficient interaction between a drifting charge carrier stream and a slow electromagnetic wave component. The suggested configuration is potentially suitable for operation in the far‐ir frequency regime. A one‐dimensional analysis of the interaction between the electromagnetic waveguide mode and the carrier current is presented, including the loss contribution due to the nonsynchronous space harmonics of the electromagnetic mode.
12 citations
TL;DR: In this article, the collisionless Boltzmann equation was used to analyze the interaction between a flowing plasma and an external slow wave structure in a collisionless regime, and the analysis was applied to a plasma consisting of drifiting charge carriers in a solid.
Abstract: Traveling‐wave interaction between flowing plasma and electromagnetic wave supported by external slow wave structure is analyzed in the collisionless regime. The plasma is described with the collisionless Boltzmann equation and the interaction is analyzed using the coupled‐mode approach. The analysis is applied to a plasma consisting of drifiting charge carriers in a solid. Illustrative examples demonstrate interaction leading to wave growth for frequencies in the far‐infrared regime. It is suggested that experimental measurement of wave growth or damping due to this effect can provide information about the velocity distribution of drifting carriers in the solid.
11 citations
01 Nov 1974
TL;DR: In this paper, the authors reported laser oscillation at 80-100°K in electrically pumped GaAs[Single Bond]Ga1-xAlxAs double-heterostructure distributed-feedback diode lasers.
Abstract: We report laser oscillation at 80–100°K in electrically pumped GaAs[Single Bond]Ga1–xAlxAs double-heterostructure distributed-feedback diode lasers. The feedback for laser oscillation was provided by a corrugated interface between the active GaAs layer and the p-Ga1–xAlxAs layer. The lowest threshold current density was 2.5 kA/cm^2 in pulsed operation. The wavelength of laser emission was 8112 A at 82°K with a half-width of less than 0.3 A. The temperature dependence of the laser wavelength was found to be smaller than that of the conventional Fabry-Perot laser.
01 Jan 1974
TL;DR: In this article, the eigenmodes of two electromagnetic modes with different frequencies whose complex amplitudes are A and B are taken as the eigens of the unperturbed medium so that they represent propagating disturbances.
Abstract: Consider two electromagnetic modes with, in general, different frequencies whose complex amplitudes are A and B. These are taken as the eigenmodes of the unperturbed medium so that they represent propagating disturbances
$$ \begin{gathered} a\left( {z,t} \right) = A{e^{i\left( {{\omega _a}t - {\beta _a}z} \right)}} \hfill \\ b\left( {z,t} \right) = B{e^{i\left( {{\omega _b}t \pm {\beta _b}z} \right)}} \hfill \\ \end{gathered} $$
(1)
with A and B constant.
01 Dec 1974
TL;DR: In this paper, a GaAs-Ga1-xAlxAs double-heterostructure distributed feedback diode laser was investigated at 80-100 K under electrical pumping.
Abstract: Lasing characteristics of GaAs-Ga1-xAlxAs double-heterostructure distributed feedback diode lasers are investigated at 80-100 K under electrical pumping. The main subjects studied here are the spectrum and mode of the distributed feedback laser and its temperature characteristics. Single longitudinal mode oscillation is observed at wavelengths which are determined by the corrugation period. The temperature dependence of the wavelength is about 1/3 that of the cleaved Fabry-Perot laser made from the same wafer.
Patent•
16 Sep 1974
TL;DR: In this article, an integrated optical detector comprising a semiconductor substrate having an optical waveguide formed integrally therewith and a photodetector made from the same semiconductor material as the waveguide and integratedrally coupled to it is described.
Abstract: There is disclosed an integrated optical detector comprising a semiconductor substrate having an optical waveguide formed integrally therewith and a photodetector made from the same semiconductor material as the waveguide and integrally coupled to it. The detector region is sensitive to light of the same wavelengths that can be transmitted through the waveguide region of the semiconductor without excessive absorption therein by virtue of the fact that after the waveguide is formed proton bombardment of the detector portion thereof is used to create optically active defect centers thereby shifting the effective absorption edge in the detector region. Where gallium arsenide is used as the semiconductor defect levels induced by implantation of high energy protons give rise to optical absorption between 6 micron and 0.9 micron. This results in detector action in the presence of a Schottkey barrier depletion layer. Detector response times less than 200 nanoseconds and external quantum efficiencies of 16 percent have been observed in the device.
TL;DR: In this paper, two main obstacles in the way of obtaining laser action in the X-ray region are identified: the first involves the pumping necessary to obtain the critical inversion, and the second one is that of the optical feedback.
Abstract: There are two main obstacles in the
way of obtaining laser action in the X-ray
region. The first involves the pumping
necessary to obtain the critical inversion.
The second one is that of the optical feedback.
01 Jan 1974
TL;DR: In this paper, a single mode TE or TM propagation is demonstrated in an optical waveguide consisting of a high resistivity semiconductor (GaAs) layer (τ= 10 μ) which is sandwiched between a metal film and a lower resistor semiconductor.
Abstract: Single mode TE or TM propagation is demonstrated in an optical waveguide consisting of a high resistivity semiconductor (GaAs) layer (τ= 10 μ) which is sandwiched between a metal film and a lower resistivity semiconductor. A reverse bias applied to the metal-semiconductor Schottky barrier causes an electro-optic retardation (or, in general, phase variation) which can be used for modulation purposes. Amplitude modulation with a “half-voltage” V1/2 = 84 volts is demonstrated at γo 1.15 μ with a sample 2.4 mm long.