Abstract: An optical bi-stable switch includes a photonic crystal cavity structure using its photonic crystal properties to characterize a bi-stable switch so that optimal control is provided over input and output of the switch. A plurality of waveguide structures are included, at least one of the waveguide structures providing the input to the switch and at least one providing the output to the switch.

Abstract: Optical signals are passed in an optical medium using an approach that facilitates the mitigation of interference. According to an example embodiment, a filtering-type approach is used with an optical signal conveyed in an optical fiber, such as a multimode fiber (MMF) or a multimode waveguide. Adaptive spatial domain signal processing, responsive to a feedback signal indicative of data conveyed in the multimode waveguide, is used to mitigate interference in optical signals conveyed in the multimode waveguide.

Abstract: 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.

Abstract: We introduce a mechanically tunable photonic crystal structure consisting of coupled photonic crystal slabs. Using both analytic theory, and first-principles finite-difference time-domain simulations, we demonstrate that the transmission and reflection coefficients for light normally incident upon such structures can be highly sensitive to nano-scale variations in the spacing between the slabs. Moreover, by specifically configuring the photonic crystal structures, the high sensitivity can be preserved in spite of significant fabrication-related disorders. We expect such a structure to play important roles in micro-mechanically tunable optical sensors and filters.

Abstract: We introduce a mechanically tunable photonic crystal structure consisting of coupled photonic crystal slabs. Using both analytic theory, and first-principles finite-difference time-domain simulations, we demonstrate that the transmission and reflection coefficients for light normally incident upon such structures can be highly sensitive to nano-scale variations in the spacing between the slabs. Moreover, by specifically configuring the photonic crystal structures, the high sensitivity can be preserved in spite of significant fabrication-related disorders. We expect such a structure to play important roles in micro-mechanically tunable optical sensors and filters.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.