Massachusetts Institute of Technology

Other

Boston University

Cambrius, Inc.

Pierre R Villeneuve

John Dimitris Joannopoulos

Shanhui Fan

Hermann A Haus

Robert D Meade

Brent Everett Little

Steven G Johnson

Leslie Kolodziejski

Elliott R Brown

Gale Petrich

Christina Manolatou

Tairan Wang

Attila Mekis

Daniel S Abrams

Oliver B McMahon

E Frederick Schubert

An electromagnetic field frequency filter which includes a bus waveguide that carries a signal having a plurality of frequencies, including a desired frequency, and a drop waveguide. A resonator-system is coupled to the bus and drop waveguides via directional couplers and transfers the desired frequency from the bus waveguide to the drop waveguide while allowing transmission of the remaining frequencies in the bus waveguide. The input signal in the bus waveguide is coupled from the bus waveguide to the resonator-system by a first directional coupler. The resonator-system includes two sub-elements each comprising at least one resonator. The first directional coupler splits the input signal into two preferably equal parts and directs each part into a resonator sub-element. The desired frequency is transferred to the drop waveguide by a second directional coupler. The non-desired frequencies are returned to the bus waveguide, in the forward direction, by the first directional coupler.

Directional-coupler assisted add/drop filter with induced on/off switching and modulation

A method of making a low-loss electromagnetic wave resonator structure. The method includes providing a resonator structure, the resonator structure including a confining device and a surrounding medium. The resonator structure supporting at least one resonant mode, the resonant mode displaying a near-field pattern in the vicinity of said confining device and a far-field radiation pattern away from the confining device. The surrounding medium supports at least one radiation channel into which the resonant mode can couple. The resonator structure is specifically configured to reduce or eliminate radiation loss from said resonant mode into at least one of the radiation channels, while keeping the characteristics of the near-field pattern substantially unchanged.

Low-loss resonator and method of making same

A highly efficient channel drop filter. The filter employs a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes. The resonator-system includes one or more interacting resonant cavities which in addition to being coupled to the waveguides, can also be coupled directly among themselves and indirectly among themselves via the waveguides. Each component of the coupling element can be configured or adjusted individually. The geometry and/or dielectric constant/refractive index of the resonator-system are configured so that the frequencies and decay rates of the resonant modes are made to be substantially the same. The filter can achieve 100% signal transfer between the waveguides at certain frequencies, while completely prohibiting signal transfer at other frequencies. In exemplary embodiments, the filter is configured with photonic crystals. In accordance with alternative embodiments of the invention, the filter is configured as an absorption induced on/off switch and modulator. The switching action is achieved with either electrical or optical absorption.

High efficiency channel drop filter with absorption induced on/off switching and modulation

An electronic transportor that allows for the resonant tunneling of electrons between guided states, such as those found in a quantum wire or a line defect in a solid, and localized states, such as those found in a quantum dot or a point defect in a solid, using lateral coupling. In some embodiments, the transporter allows electrons of different energies to be transported to different ports of associated waveguides. In other embodiments, the transportor allows electrons of different energies to be transported at different phases.

Resonant-tunneling electronic transportors

A tunable electromagnetic field frequency filter having an input waveguide which carries a signal including at least one desired frequency, and an output waveguide. A resonator-system is coupled to the input and output waveguides and is operable for the selective transfer of the at least one desired frequency to the output waveguide. The resonator-system supports at least two system modes, and includes at least three reflectors with at least two different reflectivity spectra. At least one of the reflectivity spectra is tuned such that at least two of the system-modes have substantially the same frequency when the transfer occurs substantially.

Tunable add/drop filter using side-coupled resonant tunneling

An optical waveguide structure including a first waveguide, a second waveguide that intersects with the first waveguide, and a photonic crystal resonator system at the intersection of the first and second waveguides. In accordance with another embodiment there is provided an optical waveguide crossing structure including a first waveguide that propagates signals in a first direction, a second waveguide that intersects with the first waveguide and propagates signals in a second direction, and a photonic crystal crossing region at the intersection of the first and second waveguides that prevents crosstalk between the signals of the first and second waveguides. In accordance with another embodiment of the invention there is provided an optical waveguide structure including a first waveguide, a second waveguide, and a resonator system at the intersection of the first and second waveguides, the intersection possessing a first mirror plane that is parallel to the first waveguide, the resonator system supporting a first resonant mode that includes different symmetry with guided modes in the first waveguide with respect to the first mirror plane, the resonator system substantially reduces crosstalk from the second waveguide to said first waveguide.

Optical waveguide crossings

A composite photonic crystal structure comprising a guide crystal configured in a lane having a dielectric periodicity in at least a first direction in the plane; and barrier crystals configured above and below the guide crystal to confine light within the guide crystal, the barrier crystals having a dielectric periodicity in at least a second direction not in the plane. In another embodiment, there is provided a composite photonic crystal structure comprising a guide crystal configured in a plane having a dielectric periodicity in at least one dimension; and a barrier crystal configured adjacent the guide crystal to confine light within the guide crystal, the barrier crystal having a dielectric periodicity in at least two dimensions.

Composite photonic crystals

A highly efficient channel drop filter. The filter employs a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes. The resonator-system includes one or more interacting resonant cavities which in addition to being coupled to the waveguides, can also be coupled directly among themselves and indirectly among themselves via the waveguides. Each component of the coupling element can be configured or adjusted individually. The geometry and/or dielectric constant/refractive index of the resonator-system are configured so that the frequencies and decay rates of the resonant modes are made to be substantially the same. The filter can achieve 100% signal transfer between the waveguides at certain frequencies, while completely prohibiting signal transfer at other frequencies. In exemplary embodiments, the filter is configured with photonic crystals. In accordance with alternative embodiments of the invention, there are provided channel drop filter devices with flat-top and straight-sidewall lineshape characteristics. These lineshape characteristics are realized by using several resonances to couple the waveguides, and by designing the relative positioning of the frequency of each resonance with respect to one another.

High efficiency channel drop filter

High efficiency channel drop filter with absorption induced on/off

A nonlinear dielectric material is incorporated within a photonic crystal as a means of changing the refractive index of a defect. In this way, the resonant frequency can be easily adjusted, after fabrication, by external mechanisms (either optical or electronic). The ability to tune the frequency of a resonant mode is useful for constructing photonic integrated devices, thus the invention enables the use of a photonic-crystal microcavity for such purposes. In one embodiment there is provided a photonic crystal having a periodic dielectric structure, and a defect positioned within the structure to define a microcavity. The defect includes a nonlinear material and being adapted to have an induced variation in index of refraction so as to tune the resonant mode of the microcavity.

Tunable microcavity and method of using nonlinear materials in a

A metallodielectric photonic crystal including a plurality of elements, each having a non-dielectric component, arranged with respect to each other in a three-dimensionally periodic lattice. The non-dielectric components being spatially isolated from one another, the lattice exhibiting a band gap in the spectrum of electromagnetic radiation modes propagating through said lattice. A support structure positions the elements in the three-dimensionally periodic lattice. In an exemplary embodiment, the elements are metallic spheres arranged within dielectric material. The three-dimensionally periodic lattice can include a face-centered-cubic lattice which exhibits a unidirectional photonic band gap, or a diamond lattice which exhibits an omnidirectional photonic band gap. The diamond lattice structure includes a gap width to midgap frequency ratio which can exceed 60%.

Metallodielectric photonic crystal

A light emitting device comprising a substrate and a dielectric structure having at least a two-dimensionally periodic variation of dielectric constant which exhibits a spectrum of electromagnetic modes including guided modes of frequencies below a predetermined frequency cutoff and radiation modes of frequencies above and below said predetermined frequency cutoff, the two-dimensionally periodic variation of dielectric constant of the dielectric structure introducing a band gap between the guided modes. A radiation source, such as a quantum well, is associated with said structure, and generates electromagnetic radiation which couples to the radiation modes resulting in radiation extraction from the structure. The band gap allows the radiation to couple to radiation modes rather than to guided modes resulting in radiation extraction from the structure. The structure can be fabricated such that a radiation reflector is disposed between the structure and the substrate.

Light emitting device utilizing a periodic dielectric structure

The present invention provides a resonant microcavity which includes a periodic dielectric waveguide, and a local defect in the periodic dielectric waveguide which accommodates spacial confinement of radiation generated within the waveguide around the defect. In an alternative embodiment, the present invention provides a method of enhancing radiation confinement within a resonant microcavity and minimizing radiation losses into an associated substrate, the microcavity configured within a periodic dielectric waveguide as a local defect which exhibits spacial radiation confinement, the method including the step of increasing the refractive index contrast between the microcavity and the substrate.

Resonant microcavities employing one-dimensionally periodic dielectric

A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, at least one layer having a stratum of a first material having a first dielectric constant and a plurality of parallel regions along a first axis lying in the plane of the layer, the regions including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.

Three-dimensional periodic dielectric structures having photonic bandgaps

A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, each layer having a stratum of a first material having a first dielectric constant and a plurality of parallel grooves along a first axis lying in the plane of the layer, the grooves including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.

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Boston, MA, United States of America

Pierre R Villeneuve