Abstract:
A tunable photonic crystal device comprising: alternating layers of a first material and a second material, the alternating layers comprising a responsive material, the responsive material being responsive to an external stimulus, the alternating layers having a periodic difference in refractive indices giving rise to a first reflected wavelength; wherein, in response to the external stimulus, a change in the responsive material results in a reflected wavelength of the device shifting from the first reflected wavelength to a second reflected wavelength.
Abstract:
The modulator includes a ring resonator having a phase modulator that tunes blocked wavelengths within phase modulator bandwidths. The blocked bands include blocked wavelengths at which the intensity of an output light signal is minimized. Each of the blocked bands is associated with the phase modulator bandwidth within which the blocked wavelength is tuned. A bandwidth shifting device is configured to shift a selection of wavelengths that falls within each of the phase modulator bandwidths. Electronics are configured to operate the bandwidth shifting device so as to shift the phase modulator bandwidths from a location where a first target wavelength falls within a first one of the phase modulator bandwidths to a location where a second target wavelength falls within a second one of the phase modulator bandwidths.
Abstract:
The present invention relates to a layer arrangement which changes the transmission of light depending on its temperature, where the layer arrangement has a first polarization layer, a switching layer which influences the polarization properties of light depending on the temperature, and a second polarization layer, as well as an additional NIR transmission-preventing layer.
Abstract:
An optical demultiplexer that includes at least one a hybrid phase shifter configured to receive a light signal over a fiber element, the light signal including polarized optical signals. Each phase shifter includes a thermo-optic phase shifter configured to phase shift the light signal, an electro-optic phase shifter configured to phase shift the light signal, and a coupler configured to maintain polarization of the polarized signal components. The optical demultiplexer also includes control circuitry configured to regulate the thermo-optic and electro-optic phase shifters.
Abstract:
An apparatus for optical modulation is provided. The apparatus includes a modulator structure and a heater structure. The modulator structure comprises a ring or disk optical resonator having a closed curvilinear periphery and a pair of oppositely doped semiconductor regions within and/or adjacent to the optical resonator and conformed to modify the optical length of the optical resonator upon application of a bias voltage. The heater structure comprises a relatively resistive annulus of semiconductor material enclosed between an inner disk and an outer annulus of relatively conductive semiconductor material. The inner disk and the outer annulus are adapted as contact regions for a heater activation current. The heater structure is situated within the periphery of the optical resonator such that in operation, at least a portion of the resonator is heated by radial conductive heat flow from the heater structure. The apparatus further includes a substantially annular isolation region of dielectric or relatively resistive semiconductor material interposed between the heater structure and the modulator structure. The isolation region is effective to electrically isolate the bias voltage from the heater activation current.
Abstract:
An optical limiter comprises a glass backing, a glass cover, and a layer of a phase changing material placed between said glass backing and said glass cover, the phase changing material comprising a transparent matrix having embedded particles of material that changes its optical properties due to temperature induced phase change of said material. The optical properties may change from transparent to reflective, from transparent to refractive or from transparent to scattering. The phase changing material is preferably at least one material selected from the group consisting of the elements Antimony, Bismuth, Cadmium, Lead, Tin and Indium and low-melting-point alloys of two or more of these elements. Two or more layers of phase changing materials may be used in a stack configuration, with each of the phase changing materials having a unique melting temperature.
Abstract:
Methods and apparatuses for resonance tuning of microcavities are provided. An apparatus comprises a whispering gallery mode optical microcavity characterized by at least one resonance frequency; optical components configured to evanescently couple a probe laser beam into the microcavity; an absorber element in thermal contact with the microcavity; and optical components configured to illuminate the absorber element with a free space pump light beam, wherein the absorber element is configured to absorb energy from the free space pump light beam, thereby generating heat, and to transfer the heat to the microcavity, thereby inducing a shift in the at least one resonance frequency. The absorber element may be configured as a pillar forming an interfacial region with the microcavity at one of the ends of the pillar. The surface of the microcavity may be substantially free of a coating material.
Abstract:
Wavefront synthesizers and optical switches implemented with wavefront synthesizers are disclosed. In one aspect, a wavefront synthesizer includes a waveguide tree composed a root waveguide that branches into at least two terminus waveguides. The root waveguide is integrated with a source to inject light into the waveguide tree via the root waveguide. The synthesizer includes output couplers located at the ends of the terminus waveguides. Each output coupler outputs a wavefront associated with a portion of the light injected with at least two of the wavefronts overlapping to form at least one beam of light via constructive interference. The synthesizer also includes microring resonators disposed adjacent to the terminus waveguides. Each microring is independently tunable to apply a phase shift in the wavefront output from one of the output couplers to steer the direction of the beam and the at least two wavefronts.
Abstract:
Methods and apparatuses for single particle and single molecule spectroscopy are provided. A method comprises exposing the surface of an optical microcavity characterized by at least one resonance frequency to a sample such that a single particle or a single molecule from the sample adsorbs onto the surface of the microcavity; evanescently coupling a probe laser beam into the microcavity, wherein the wavelength of the probe laser beam substantially matches the at least one resonance frequency; illuminating the surface of the microcavity with a free space pump light beam such that the focal spot of the free space pump light beam substantially overlaps with the single particle or the single molecule; and detecting light from the probe laser beam, wherein the wavelength of the free space pump light beam is that which generates sufficient heat via energy absorbed by the single particle or the single molecule from the free space pump light beam to induce a shift in the at least one resonance frequency, thereby providing a change in an optical characteristic of the detected light from the probe laser beam.
Abstract:
An tunable optical frequency comb source includes a linear waveguide having an input leg to couple to a pump laser. A ring microresonator is evanescently coupled to the linear waveguide. The microresonator includes a ring shaped waveguide having a core material with a nonlinear refractive index to provide four-wave mixing to generate a cascade of independent laser beams at frequencies corresponding to the longitudinal modes of the microresonator.