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Author

Giora Griffel

Bio: Giora Griffel is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Power dividers and directional couplers & Semiconductor laser theory. The author has an hindex of 4, co-authored 7 publications receiving 122 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a grating-assisted directional coupler is investigated using an improved coupled-mode formulation for multi-waveguide systems with longitudinal perturbation, which is capable of handling three-dimensional structures as well as a complex index of refraction and nonisotropic media.
Abstract: A grating-assisted directional coupler is investigated using an improved coupled-mode formulation for multi-waveguide systems with longitudinal perturbation. This approach is capable of handling three-dimensional structures as well as a complex index of refraction and nonisotropic media. The case of two coupled channel waveguides is closely examined, and a numerical analysis is carried out for several cases of slab structures. >

45 citations

Journal ArticleDOI
TL;DR: In this paper, the spectral properties of grating-assisted directional couplers were studied using an improved coupled mode formulation, and the parameters for the design of these structures, such as the grating period, the coupling length and other structural parameters, were calculated.
Abstract: The spectral properties of grating-assisted directional couplers are studied using an improved coupled mode formulation. Key parameters for the design of these structures, such as the grating period, the coupling length, and other structural parameters, are calculated. The frequency response, the filter bandwidth, and the tuning range are analyzed. The technique is used to examine a specific case of InGaAsP-InP tunable filters, and the results are compared to a prior experiment. >

39 citations

Journal ArticleDOI
TL;DR: In this article, a monolithic integration of a double barrier AlAs/GaAs resonant tunneling diode and a GaAs/AlGaAs quantum well laser is reported.
Abstract: A monolithic integration of a double barrier AlAs/GaAs resonant tunneling diode and a GaAs/AlGaAs quantum well laser is reported. Negative differential resistance and negative differential optical response are observed at room temperature. The device displays bistable electrical and optical characteristics which are voltage controlled. Operation as a two‐state optical memory is demonstrated.

23 citations

Journal ArticleDOI
TL;DR: In this paper, a monolithic, laterally coupled semiconductor stripe laser with a tuning range of 14.2 nm has been demonstrated. But the tuning range is not yet known for a single longitudinal mode spectrum.
Abstract: Tunable, single longitudinal mode spectrum of a novel monolithic, laterally coupled semiconductor stripe laser has been demonstrated. A tuning range of 14.2 nm, which is the widest observed so far in a monolithic device, has been achieved.

10 citations

Journal ArticleDOI
TL;DR: Frequency selectivity of a novel type of multielement, multisection laterally coupled semiconductor laser array is studied using the round-trip method and the experimental results show excellent agreement with the theoretical prediction.
Abstract: Frequency selectivity of a novel type of multielement, multisection laterally coupled semiconductor laser array is studied using the round-trip method. It is found that such a structure should lead to a strong frequency selectivity owing to a periodic dependency of the threshold gain on the frequency. A gain-guided two-coupled-cavity device was fabricated. The experimental results show excellent agreement with the theoretical prediction.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a review of the recent development of coupled-mode theory for optical waveguides is given, with emphasis on the analysis of coupled optical waveguide, and three typical coupler configurations (uniform, grating-assisted, and tapered) are examined in detail.
Abstract: The coupled-mode theory (CMT) for optical waveguides is reviewed, with emphasis on the analysis of coupled optical waveguides. A brief account of the recent development of the CMT for coupled optical waveguides is given. Issues raised in the debates of the 1980’s on the merits and shortcomings of the conventional as well as the improved coupled-mode formulations are discussed. The conventional coupled-mode formulations are set up in a simple, intuitive way. The rigorous CMT is established on the basis of a linear superposition of the modes for individual waveguides. The cross-power terms appear logically as a result of modal nonorthogonality. The cross power is necessary for the self-consistency of the CMT for dissimilar waveguides. The nonorthogonal CMT, though more complicated, yields more-accurate results than the conventional orthogonal CMT for most practical applications. It also leads to the prediction of cross talk in directional couplers. The conventional orthogonal CMT is, however, reliably accurate for describing the power coupling between two weakly coupled, nearly identical waveguides. For dissimilar waveguides, a self-consistent orthogonal CMT can be derived by a redefinition of the coupling coefficients, and it predicts the coupling length and therefore the power exchange between the waveguides accurately if the two waveguides are far apart. Three typical coupler configurations—the uniform, the grating-assisted, and the tapered—are examined in detail. The accuracy, scope of validity, limitations, and extensions of the coupled-mode formulations are discussed in conjunction with each configuration. To verify the arguments in the discussions, comparisons with the exact analytical solutions and the rigorous numerical simulations are made.

691 citations

Patent
19 Apr 1999
TL;DR: In this paper, an optical coupler is used to couple two optical waveguides (50, 60) and an optical switch based on the optical coupling mechanism, where the indices of refraction of parallel sections of the two waveguiders are reversibly perturbed periodically in space by imposing a mechanism (58, 68, 59, 69) to couple low order modes in the two Waveguides via a high order mode common to the twoWaveguides.
Abstract: An optical coupler, for coupling two optical waveguides (50, 60), and an optical switch based on the optical coupler. The indices of refraction of parallel sections of the two waveguides (50, 60) are reversibly perturbed periodically in space by imposing a mechanism (58, 68, 59, 69) to couple low order modes in the two waveguides via a high order mode common to the two waveguides. The waveguides are thus coupled with a beat length that may be five or more orders of magnitude shorter than it would be without the periodic perturbations.

127 citations

Journal ArticleDOI
TL;DR: The transmission-line representation can serve as a template for computational algorithms that systematically evaluate dispersion properties, radiation effects, wave coupling and other characteristics that are not readily obtained by other methods.
Abstract: Solutions to problems involving the scattering and guiding of waves by multilayered grating configurations can be phrased in rigorous modal terms. We show that such a modal solution can be represented by electrical transmission-line networks, which are generalized forms of simpler conventional circuits. This approach brings considerable physical insight into the grating diffraction process and facilitates the derivation of the fields everywhere. In particular, the transmission-line representation can serve as a template for computational algorithms that systematically evaluate dispersion properties, radiation effects, wave coupling and other characteristics that are not readily obtained by other methods. Examples illustrating the application of the present approach are given for waves guided by grating configurations encountered in optoelectronic devices.

115 citations

Journal ArticleDOI
TL;DR: In this paper, the first demonstration of broadly electrically tunable (215 A), narrowband (∼20 A full width at half maximum), wavelength selective, grating assisted coupling between vertically stacked buried rib InGaAsP/InP channel waveguides was presented.
Abstract: We report the first demonstration of broadly electrically tunable (215 A), narrow‐band (∼20 A full width at half maximum), wavelength selective, grating‐assisted coupling between vertically stacked buried rib InGaAsP/InP channel waveguides. This current injection tuned device is suitable for integration in a variety of photonic devices and integrated circuits including broadly tunable extended cavity lasers, amplifier/filter, and demultiplexer/detector circuits.

66 citations

Journal ArticleDOI
TL;DR: In this paper, a grating-assisted directional coupler is investigated using an improved coupled-mode formulation for multi-waveguide systems with longitudinal perturbation, which is capable of handling three-dimensional structures as well as a complex index of refraction and nonisotropic media.
Abstract: A grating-assisted directional coupler is investigated using an improved coupled-mode formulation for multi-waveguide systems with longitudinal perturbation. This approach is capable of handling three-dimensional structures as well as a complex index of refraction and nonisotropic media. The case of two coupled channel waveguides is closely examined, and a numerical analysis is carried out for several cases of slab structures. >

45 citations