An optical system has a beam-steering device having a planar waveguide region between a tapered incoupler and a tapered outcoupler that respectively define opposing incoupler and outcoupler facets of the BS device. Each region has a substrate, a subcladding layer over the substrate, a core layer over the subcladding, and a top cladding layer over the core. Within the incoupler, at least one of the subcladding and the top cladding has a material having a refractive index that varies with an applied field (e.g., an electric field) applied at the incoupler. The optical system also has a field-applying device that applies the applied field at the incoupler, an output detector that generates a feedback signal based on detected outgoing light output from the outcoupler, and a controller that controls the field-applying device based on the feedback signal to alter the light output from the outcoupler.

A beam-steering device, such as a steerable electro-evanescent optical refractor, has a planar waveguide region between an incoupler and an outcoupler. Each region has a substrate and a plurality of thin-film layers, such as a subcladding layer over the substrate and a core layer over the subcladding. For at least one coupler, at least two of the thin-film layers have spatially varying optical thicknesses due to, for example, the subcladding and the core being tapered with decreasing thicknesses from the waveguide region to the corresponding facet of the BS device. Alternatively, spatially varying optical thickness can be achieved by spatially varying a layer's refractive index. The coupler has a FWHM bandwidth and a FWHM coupling angle tolerance that greatly exceed those achievable using conventional Ulrich couplers.

A control apparatus for generating a control signal for an electro-optic modulator is described. The control apparatus includes an RF signal source being configured to generate a radio frequency (RF) signal. The control apparatus further includes an amplitude adjustment circuit being configured to adjust an amplitude of the RF signal, thereby obtaining an adjusted RF signal. The control apparatus further includes a DC signal source being configured to generate a direct current (DC) signal. The control apparatus further includes a superposition circuit being configured to superimpose the adjusted RF signal and the DC signal, thereby obtaining the control signal for the electro-optic modulator. The control apparatus further includes a control circuit, wherein the control circuit is configured to receive at least one frequency parameter associated with the electro-optic modulator. The at least one frequency parameter includes a frequency multiplication factor and/or a target modulation frequency. The control circuit is configured to control the DC signal source to adapt a voltage of the DC signal based on the at least one frequency parameter received. Further, an optical signal generator apparatus and an RF-over-fiber system are described.

Aspects of the present disclosure are directed to a photorefractive layer stack. A plurality of layers are stacked along in a stacking direction and designed so as to enable a photorefractive response. That is, a refractive index of the plurality of layers modulates in response to illuminating the plurality of layers with an optical pattern of modulated intensity. A plurality of electrically insulated areas are arranged in a plane perpendicular to the stacking direction. The plurality of electrically insulated areas are optically homogenous and prevent lateral diffusion between any two electrically insulated areas of the plurality of electrically insulated areas.

Application of an electric field to nanorods can control their alignment, thus providing techniques for ultra-fast switching and optical modulators, for example those that might serve as display indicators.

A method for in situ synthesis of graphene along a lengthwise direction of a waveguide applied to a photonic device includes processing an evanescent field of laser propagating in the waveguide to spread outward the waveguide, depositing a nickel thin film on a surface of the waveguide, growing graphene between a surface of the waveguide and a nickel thin film by irradiating telecommunication laser to a core of the waveguide, and removing the nickel thin film from the waveguide. Accordingly, graphene with high optical nonlinearity is in situ synthesized in the photonic device.

Ring modulators based on interdigitated junctions may be driven in full or partial standing wave mode and, active regions (providing the modulation) and light-absorptive regions (e.g. providing electrical conduction) are placed in a pattern inside a resonant cavity in order to match the maxima and minima of the optical field, respectively. The pattern may be periodic to match the periodicity of a typical electromagnetic field which is periodic with the wavelength. It may also be aperiodic in the case that the cross-section or materials are engineered along the direction of propagation such that the propagation constant (and thus wavelength, i.e. optical wave local periodicity) change along the propagation direction.

A fiber ring resonator having a relatively long loop of standard single-mode fiber with a short nanofiber segment. The evanescent mode of the nanofiber segment allows the cavity-enhanced field to interact with atoms in close proximity to the nanofiber surface.

A loop memory cell (LMC) includes a minimum of one optical loop coupled by a minimum of one input armlet and on output armlet. The input armlet(s) can couple only in one direction, from the input armlet(s) into the optical loop, and not back. The output armlet(s) can couple or not, according to the refractive index changer, from the optical loop into the output armlet(s). The LMC is configured to collect the input data and store the date in the optical loop until needed. Changing the refractive index the LMC can act as a memory cell or modulator. The LMC overcomes the energy loss of conventional techniques, allowing the creation of variety of building blocks and complex processing blocks for different applications and algorithms. The LMC has increased information storing efficiency, increased data processing speeds, and can modulate data thereby reducing processing complexity and increasing speeds.

A non-mechanical optical beam steering device includes one or more polarization gratings (PG) coupled to one or more Steerable Electro-Evanescent Optical Refractors (SEEOR). It provides the coarse steering advantage of the PG and also the continuous fine steering advantage of the SEEOR. The result is far less complexity, size, weight, and cost over the alternative non-mechanical beam steering approaches as well as considerably less complexity, size, weight, cost, scanning-time, and mechanical breakdown over the more traditional gimbaled mirrors commonly used.