Abstract: An antenna comprises a ring-shaped radiofrequency resonator that defines a path for a circulating magnetic current. In an implementation, the resonator has a height of no more than 2% of an operating wavelength, and it has an electromagnetic resonance at the operating frequency. In an implementation, the antenna is of a type having a vertical, short electric dipole radiation or sensitivity pattern. It comprises, as the dominant radiative element, a ring of material disposed transverse to the vertical dipole axis and having an average magnetic permeability more than ten times the magnetic permeability of air. The ring has a maximum outer diameter and a height that is less than the maximum outer diameter. The antenna further includes a feed structure adapted to couple radiofrequency energy into and/or out of a magnetic current circulating in the ring.

Abstract: An antenna comprises a ring-shaped radiofrequency resonator that defines a path for a circulating magnetic current. In an implementation, the resonator has a height of no more than 2% of an operating wavelength, and it has an electromagnetic resonance at the operating frequency. In an implementation, the antenna is of a type having a vertical, short electric dipole radiation or sensitivity pattern. It comprises, as the dominant radiative element, a ring of material disposed transverse to the vertical dipole axis and having an average magnetic permeability more than ten times the magnetic permeability of air. The ring has a maximum outer diameter and a height that is less than the maximum outer diameter. The antenna further includes a feed structure adapted to couple radiofrequency energy into and/or out of a magnetic current circulating in the ring.

Abstract: A representative embodiment of the invention provides an antenna having an electrically conducting ground plane and an array of electrically conducting strips located at an offset distance from the ground plane. Electrically conducting pathways, each attached to the middle portion of the corresponding strip, connect the strips to the ground plane. Electrically conducting lips, each attached to an edge of the corresponding conducting strip, extend about halfway toward the ground plane. The size of the array is smaller than the wavelength of the fundamental radiation mode supported by the antenna. Advantageously, the antenna has a bandwidth about three times larger than that of a comparably sized prior-art patch antenna.

Abstract: In one embodiment, the present invention is a dual-polarized antenna array constructed from first and second instances of a planar antenna that are co-located and orthogonal to one another. The planar antenna comprises three conducting elements and a transmission line. The first conducting element comprises a straight segment and two arms of equal length. The proximal ends of the two arms are attached to opposite ends of the straight segment. The arms extend away from the second and third conducting elements and towards one another. The second and third conducting elements are separated by a gap and together form a mirror image of the first conducting element. The transmission line has first and second conductors that are coupled to the second and third conducting elements, respectively. In another embodiment, the present invention is a tri-polarized antenna array constructed from three orthogonal co-located instances of the planar antenna.

Abstract: An antenna is provided for operating within the electrically small antenna regime (i.e., ka?0.5), and having bandwidth performance quite close to fundamental limits. The antenna of the invention, in various embodiments, is based upon spherical resonator structures that are characterized by a performance factor (Q/Qchu,) close to 1.5. The antenna combines a resonator structure determined according to the method of the invention with an appropriate transmission line feeding arrangement, such that the resonator effectively couples the transmission line mode to the radiating spherical harmonic mode in an impedance-matched manner.

Abstract: In one embodiment, the present invention is a dual-polarized antenna array constructed from first and second instances of a planar antenna that are co-located and orthogonal to one another. The planar antenna comprises three conducting elements and a transmission line. The first conducting element comprises a straight segment and two arms of equal length. The proximal ends of the two arms are attached to opposite ends of the straight segment. The arms extend away from the second and third conducting elements and towards one another. The second and third conducting elements are separated by a gap and together form a mirror image of the first conducting element. The transmission line has first and second conductors that are coupled to the second and third conducting elements, respectively. In another embodiment, the present invention is a tri-polarized antenna array constructed from three orthogonal co-located instances of the planar antenna.

Abstract: An optical data signal can be sampled by linearly combining the optical data signal with optical sampling pulses, and delivering the combination to first and second balanced detectors. The optical data signal and the optical sampling pulse are configured to have a first phase difference at the first balanced detector and a second phase difference at the second balanced detector. Typically, a difference between the first phase difference and the second phase difference is configured to be about 90 degrees. In-phase and quadrature balanced detector outputs can be combined as a sum of squares to produce a linear sampling signal representative of data signal intensity, and the sample pulses can be configured to temporally step through the optical data signal so that a sampled representation of the optical data signal is obtained.

Abstract: An optical performance monitor (OPM), e.g., for use in an optical network. The OPM may be configured to characterize one or more impairments in an optical signal modulated with data. The OPM has an optical autocorrelator configured to sample the autocorrelation function of the optical signal, e.g., using two-photon absorption. Autocorrelation points at various bit delays independently or in combination with average optical power may be used to detect and/or quantify one or more of the following: loss of data modulation, signal contrast, pulse broadening, peak power fluctuations, timing jitter, and deviations from the pseudo-random character of data. In addition, the OPM may be configured to perform Fourier transformation based on the autocorrelation points to obtain corresponding spectral components. The spectral components may be used to detect and/or quantify one or more of chromatic dispersion, polarization mode dispersion, and misalignment of a pulse carver and data modulator.

Abstract: A representative embodiment of the invention provides an antenna having an electrically conducting ground plane and an array of electrically conducting strips located at an offset distance from the ground plane. Electrically conducting pathways, each attached to the middle portion of the corresponding strip, connect the strips to the ground plane. Electrically conducting lips, each attached to an edge of the corresponding conducting strip, extend about halfway toward the ground plane. The size of the array is smaller than the wavelength of the fundamental radiation mode supported by the antenna. Advantageously, the antenna has a bandwidth about three times larger than that of a comparably sized prior-art patch antenna.

Abstract: An antenna is provided for operating within the electrically small antenna regime (i.e., ka?0.5), and having bandwidth performance quite close to fundamental limits. The antenna of the invention, in various embodiments, is based upon spherical resonator structures that are characterized by a performance factor (Q/Qchu,) close to 1.5. The antenna combines a resonator structure determined according to the method of the invention with an appropriate transmission line feeding arrangement, such that the resonator effectively couples the transmission line mode to the radiating spherical harmonic mode in an impedance-matched manner.

Abstract: An optical performance monitor (OPM) adapted to (i) sample an autocorrelation function corresponding to an optical signal transmitted in an optical network and (ii) based on the sampling, characterize two or more impairments concurrently present in the optical signal. In one embodiment, the OPM has an optical autocorrelator (OAC) coupled to a signal processor (SP). The OAC receives the optical signal from the network, generates two or more samples of its autocorrelation function, and applies said samples to the SP. The SP processes the samples and generates two or more signal metrics. Based on the signal metrics and reference data corresponding to the impairments, the SP then obtains a measure of each of the impairments.

Abstract: In one embodiment, a waveguide lens of the invention has a pair of planar waveguides, e.g., a single-mode waveguide connected to a multimode waveguide. The widths of the two waveguides and the length of the multimode waveguide are selected such that particular mode coupling between the waveguides and multimode interference (MMI) effects in the multimode waveguide cause the latter to output a converging beam of light similar to that produced by a conventional waveguide lens. Advantageously, waveguide lenses of the invention may be used to implement low-loss, low-crosstalk waveguide crossings and/or compact waveguide turns. In addition, waveguide lenses of the invention can be readily and cost-effectively incorporated into waveguide devices designated for large-scale production.

Abstract: An optical device has at least one waveguide with at least one adjacent resonator, where the distance between the resonator and the waveguide can be controllably adjusted to change the optical coupling between the resonator and the waveguide. When implemented as part of an interferometer, the ability to adjust the waveguide/resonator distance—and thereby the optical coupling between them—provides a mechanically tunable interferometer.

Abstract: A MEMS optical switch includes a movable cantilevered beam with a waveguide corresponding to one port of the switch. The beam is designed for in-plane motion and can be deflected, e.g., using a three-electrode motion actuator having one electrode on each side of the beam, which itself acts as the third electrode. The beam moves toward a side electrode in response to a voltage difference applied between the beam and that electrode. The beam has two terminal positions, each defined by a stopper. At each terminal position, a bumper portion of the beam is pushed against a corresponding stopper, which aligns the waveguide in the beam with one of two stationary waveguides, each corresponding to a port of the switch. The MEMS switch may be fabricated using a single silicon-on-insulator (SOI) wafer.

Abstract: A MEMS optical switch includes a movable cantilevered beam with a waveguide corresponding to one port of the switch. The beam is designed for in-plane motion and can be deflected, e.g., using a three-electrode motion actuator having one electrode on each side of the beam, which itself acts as the third electrode. The beam moves toward a side electrode in response to a voltage difference applied between the beam and that electrode. The beam has two terminal positions, each defined by a stopper. At each terminal position, a bumper portion of the beam is pushed against a corresponding stopper, which aligns the waveguide in the beam with one of two stationary waveguides, each corresponding to a port of the switch. The MEMS switch may be fabricated using a single silicon-on-insulator (SOI) wafer.

Abstract: A method and apparatus for preparing groups of low duty cycle WDM transmission channels such that each group can be demultiplexed either via conventional WDM (e.g., by optically filtering each channel and receiving that channel at its line rate) or via TDM (e.g., directing an entire group of WDM channels onto a signal higher speed detector, receiving them all and demultiplexing the channels in a temporal (electronic) domain).

Abstract: An optical performance monitor (OPM), e.g., for use in an optical network. The OPM may be configured to characterize one or more impairments in an optical signal modulated with data. The OPM has an optical autocorrelator configured to sample the autocorrelation function of the optical signal, e.g., using two-photon absorption. Autocorrelation points at various bit delays independently or in combination with average optical power may be used to detect and/or quantify one or more of the following: loss of data modulation, signal contrast, pulse broadening, peak power fluctuations, timing jitter, and deviations from the pseudo-random character of data. In addition, the OPM may be configured to perform Fourier transformation based on the autocorrelation points to obtain corresponding spectral components. The spectral components may be used to detect and/or quantify one or more of chromatic dispersion, polarization mode dispersion, and misalignment of a pulse carver and data modulator.

Abstract: A waveguide for optical transmission having a mechanically active core material comprised of a silicon-rich silicon nitride in a mechanically active region. In the mechanically active region, the silicon-rich silicon nitride core can have no cladding (ie. an air cladding) or a cladding comprised of a silicon nitride over at least a portion thereof. The silicon-rich silicon nitride core is comprised of a silicon nitride compound having a ratio of silicon to nitrogen atoms greater than that of stoichiometric silicon nitride, Si3N4.