Abstract: A variable optical device for controlling the propagation of light has a liquid crystal layer (1), electrodes (4) arranged to generate an electric field acting on the liquid crystal layer, and an electric field modulation layer (3,71) arranged between the electrodes and adjacent the liquid crystal layer for spatially modulating said electric field in a manner to control the propagation of light passing through said optical device. The electric field modulation layer has either an optical index of refraction that is essentially spatially uniform, or a polar liquid or gel, or a very high low frequency dielectric constant material having a dielectric constant greater than 20, and preferably greater than 1000.

Abstract: Variable liquid crystal devices for controlling the propagation of light through a liquid crystal layer use a frequency dependent material to dynamically reconfigure effective electrode structures in the device. The frequency of a drive signal that generates an electric field in the device may be varied, and the frequency dependent material has different charge mobilities for the different frequencies. At a low charge mobility, the frequency dependent material has little effect on the existing electrode structures. However, at a high charge mobility, the frequency dependent material appears as an extension of the fixed electrodes, and may be used to change the effective electrode structure and, thereby, the spatial profile of the electric field. This, in turn, changes the optical properties of the liquid crystal, thus allowing the optical device to be frequency controllable.

Abstract: A liquid crystal optical device has a layered structure with split liquid crystal layers having alignment surfaces that define in a liquid crystal material pre-tilt angles of opposite signs. Four liquid crystal layers can provide two directions of linear polarization. In the case of a lens, the device can be a gradient index lens, and the alignment surfaces can have a spatially uniform pre-tilt.

Abstract: A variable optical device for controlling the propagation of light has a liquid crystal layer (1), electrodes (4) arranged to generate an electric field acting on the liquid crystal layer, and an electric field modulation layer (3,71) arranged between the electrodes and adjacent the liquid crystal layer for spatially modulating said electric field in a manner to control the propagation of light passing through said optical device. The electric field modulation layer has either an optical index of refraction that is essentially spatially uniform, or a polar liquid or gel, or a very high low frequency dielectric constant material having a dielectric constant greater than 20, and preferably greater than 1000.

Abstract: A variable focus liquid crystal lens includes a nematic liquid crystal/monomer mixture having a spatially inhomogenous polymer network structure, and an electrode for applying a substantially uniform voltage to the nematic liquid crystal/monomer mixture. The lens is created within a cell by applying a substantially uniform electric field to the nematic liquid crystal/monomer mixture within the cell, while simultaneously irradiating the nematic liquid crystal/monomer mixture using a laser beam having a shaped intensity distribution, so as to induce formation of a spatially inhomogenous polymer network structure within the cell.

Abstract: A camera module and method for focusing a tunable lens configured to continuously vary its optical power in response to a drive signal. A drive circuit generates the drive signal so that the tunable lens performs a continuous scan of its optical power. An image sensor is configured to acquire light images passing through the tunable lens, and to convert the light images to image signals during the continuous scan. A processor is configured to generate focus scores of the acquired light images using the image signals during the continuous scan. The processor is configured to determine from the focus scores a peak focus score achieved or achievable, and to instruct the drive circuit to adjust the drive signal so that the tunable lens settles at a value of the optical power that corresponds to the peak focus score.

Abstract: A variable focus liquid crystal lens includes a nematic liquid crystal/monomer mixture having a spatially inhomogenous polymer network structure, and an electrode for applying a substantially uniform voltage to the nematic liquid crystal/monomer mixture. The lens is created within a cell by applying a substantially uniform electric field to the nematic liquid crystal/monomer mixture within the cell, while simultaneously irradiating the nematic liquid crystal/monomer mixture using a laser beam having a shaped intensity distribution, so as to induce formation of a spatially inhomogenous polymer network structure within the cell.

Abstract: An electromagnetic source has an electrode structure coupled to a substrate. The electrode structure has interspaced electrodes, at least one of which is spiral-shaped. At least one electrical contact interconnects the electrodes of the electrode structure. The electrode structure is responsive to an applied electrical current to generate a spatially non-uniform magnetic field. This field can act on a LC layer such that optical properties of the layer are controllable.

Abstract: A tunable-focusing liquid crystal lens (TLCL) cell has a liquid crystal layer arranged within a cell gap defined between substrates, a layer of optically transparent material arranged between the first substrate and the LC layer, and a liquid crystal alignment layer arranged between the optically transparent layer and the LC layer. The alignment layer is provided on a third optically transparent substrate having a non-planar shape for giving a non-planar profile to the LC layer, which substrate is obtained from a flexible sheet initially provided with the alignment layer and then formed into the non-planar shape. The lens further has a first optically transparent electrode provided on the second substrate, a second optically transparent electrode provided on either or both of first and third substrates. The electrodes are arranged to generate an electric field acting on the LC layer to change the focal distance of the LC cell.

Abstract: A tunable optical imaging system uses a fixed lens and a tunable liquid crystal lens that is operated only outside of an operational range of high aberration. A voltage range applied to change the optical power of the liquid crystal lens is limited to a continuous tunable range of low aberration. The relative positioning between the lens and a corresponding photodetector, and the relative lens powers of a fixed lens and the tunable lens, may be selected to compensate for any optical power offsets resulting from the limitation of the voltage range of the tunable lens. The lens may be operated in either positive tunability or negative tunability mode.

Abstract: A device and method for the spectrally-designed and controlled attenuation of a light signal, including an attenuation structure which may be placed in the proximity of a waveguide's core and which comprises a base material system containing non-uniformities having optical properties that are different from those of the host. These non-uniformities may have various natures, geometrical forms and sizes and may be created, doped or otherwise introduced in the base material system to obtain externally controllable optical properties of the whole composite material providing a broadband spectral performance.

Abstract: A variable optical device for controlling the propagation of light has a liquid crystal layer (1), electrodes (4) arranged to generate an electric field acting on the liquid crystal layer, and an electric field modulation layer (3,71) arranged between the electrodes and adjacent the liquid crystal layer for spatially modulating said electric field in a manner to control the propagation of light passing through said optical device. The electric field modulation layer has either an optical index of refraction that is essentially spatially uniform, or a polar liquid or gel, or a very high low frequency dielectric constant material having a dielectric constant greater than 20, and preferably greater than 1000.

Abstract: A variable focus liquid crystal lens includes a nematic liquid crystal/monomer mixture having a spatially inhomogenous polymer network structure, and an electrode for applying a substantially uniform voltage to the nematic liquid crystal/monomer mixture. The lens is created within a cell by applying a substantially uniform electric field to the nematic liquid crystal/monomer mixture within the cell, while simultaneously irradiating the nematic liquid crystal/monomer mixture using a laser beam having a shaped intensity distribution, so as to induce formation of a spatially inhomogenous polymer network structure within the cell.

Abstract: A variable focus liquid crystal lens includes a nematic liquid crystal/monomer mixture having a spatially inhomogenous polymer network structure, and an electrode for applying a substantially uniform voltage to the nematic liquid crystal/monomer mixture. The lens is created within a cell by applying a substantially uniform electric field to the nematic liquid crystal/monomer mixture within the cell, while simultaneously irradiating the nematic liquid crystal/monomer mixture using a laser beam having a shaped intensity distribution, so as to induce formation of a spatially inhomogenous polymer network structure within the cell.

Abstract: In a method for coupling an optical waveguide to a light emitting diode (LED) within a resin case, an input end of the optical waveguide is mounted proximal to a surface formed in the resin case parallel to a light-emitting face of the LED. The optical waveguide and the resin case can be bonded by a light or thermally curable resin that is applied and subsequently solidified. The light or thermally curable resin may be a photopolymer sensitive to light emerging from the waveguide. An automated coupling system is provided to optimize the coupling conditions using the in-coupled light efficiency feedback and controller. Finally a method is described allowing the coupling efficiency to be controlled using external excitation forces or light intensity variations, using electro-optic, magneto-optic, thermo-optic, light polarization sensitive or nonlinear properties of the filler material used between the resin case and waveguide.

Abstract: A variable optical attenuator comprises a portion of a waveguide through which optical energy can propagate having a side surface through which optical energy can be extracted; a layer of thermo sensitive material having controllable optical properties, covering the side surface of the portion; a helicoidal heating element wrapped around the waveguide and covering at least the layer. The helicoidal heating element can be used to control the optical properties of the material by inducing a thermal transfer profile on the material using the heat dissipation of the heater through the material; wherein a wave propagation in the waveguide is influenced by the optical properties of the material controlled by the heating element.

Abstract: Described is a composite liquid crystalline mixture having a low refractive index and a chemical reactive power that makes it capable of minimizing an anchoring energy when in contact with silica. This mixture comprises: (a) low ordinary refractive index nematic liquid crystal of a single type or a mixture of low ordinary refractive index nematic liquid crystals of different types; (b) at least one reagent compound capable of reducing the anchoring energy via a chemical shielding process and from which originates a decoupling effect with a glass interface leading to the reduction of the anchoring energy and appropriately orienting a liquid crystal director at this interface; and (c) at least one low refractive index additive having a relatively low viscosity. The above mixture is useful in waveguide tuning applications.

Abstract: A device and method for the spectrally-designed and controlled attenuation of a light signal, including an attenuation structure which may be placed in the proximity of a waveguide's core and which comprises a base material system containing non-uniformities having optical properties that are different from those of the host. These non-uniformities may have various natures, geometrical forms and sizes and may be created, doped or otherwise introduced in the base material system to obtain externally controllable optical properties of the whole composite material providing a broadband spectral performance.

Abstract: A variable optical device for selectively controlling propagation of light within an optical waveguide. The optical device comprises: a relief modulation defining a grating disposed proximal the waveguide and having a respective grating index of refraction nG; a matrix surrounding at least the relief modulation, the matrix having an index of refraction nEO that is controllable, in response to a selected stimulus between a first value that is substantially equal to the grating index of refraction nG, and a second value that is different from nG; and at least one electrode for supplying the selected stimulus to the matrix-grating system.

Abstract: A material composition for optically coupling two optical components, a method for making such a coupling and the resulting device are provided. The material composition includes a first material system polymerizable by light, and a second material system having a refractive index smaller than that of the first material system after its polymerization. The second material system is miscible with the first prior to its polymerization, but repulsed by it afterwards. The material composition is injected between two optical components, such as a light source and waveguide or two waveguides, and exposed to light beams from both sides to generate a light guiding channel therebetween. The transverse refractive index profile in the coupling region is W-shaped.