Abstract: A method for wireless data transmission between a transmitter and a receiver includes modulating signals onto an electromagnetic carrier wave in a frequency range between 0.1 and 10 terahertz, and transmitting the carrier wave by the transmitter and focusing the transmitted carrier wave in the direction of the receiver. The transmitter is aimed towards the receiver by an adjusting system using a wireless communication link between the transmitter and the receiver so as to provide automatic aiming.

Abstract: A method for influencing electromagnetic radiation in a frequency range between 0.1 and 10 terahertz includes providing a planar modulator having a matrix of at least 10×10 individual, active planar elements. Each planar element has a diameter between 5 ?m and 100 ?m. The planar elements are individually controlled using a central control unit such that each planar element assumes a respective one of at least two states in accordance with the control so as to influence the radiation.

Abstract: A method for processing received electromagnetic radiation includes receiving electromagnetic radiation having a plurality of carrier waves in the frequency range between 0.1 and 10 terahertz and having modulated onto the carrier waves information with a signal frequency of less than 50 GHz. The received radiation is filtered with a filter that is tunable in the frequency range from 0.1 to 10 terahertz so as to obtain at least one carrier wave as a terahertz signal. The terahertz signal is provided to a detection circuit that is sensitive to the terahertz signal frequency.

Abstract: A method for producing an electromagnetic carrier wave in the frequency range between 0.1 and 10 terahertz that is suitable for the wireless transmission of data includes generating, by an electromagnetic pump wave, at least two mixing waves with a defined frequency difference, the pump wave being configured to constitute one of the mixing waves; and producing an electromagnetic carrier wave by frequency mixing the mixing waves.

Abstract: Method for preparing a purified crystal for use in an optical component, from an impure crystal having impurities or crystal defects capable of causing a specific absorption of incident light, includes heating the impure crystal to a temperature at which ions in the crystal are mobile and provide conductivity. A part of the crystal is illuminated with an electromagnetic purifying beam having a frequency in or near a visible frequency range so as to optically excite and migrate charges in the crystal, the charges being compensated by a counter-migration of the ions so as to be fixed in place thereafter so as to provide a purified crystal zone. The crystal is cooled to a future operating temperature.

Abstract: Method for treating a nominally pure crystal having non-linear optical properties. The nominally pure crystal contain foreign atoms at a residual concentration of less than 20 ppm so as to provide specific absorption of incident light. The method includes determining, based on testing on a specifically doped reference crystal of same type as the nominally pure crystal, a threshold value. The threshold value is defined by a temperature at which a migration of ions in the nominally pure crystal to the surface of the nominally pure crystal ceases. The foreign atoms are transformed to a higher valance state by a thermally-supported oxidation process including heating the nominally pure crystal at a heating rate that increases by less than 3 ° C. per minute to a maximum temperature above the threshold value and below a Curie temperature of the nominally pure crystal. An electrical voltage is applied so as to eliminate electrons released during the oxidation process from the nominally pure crystal.

Abstract: A method for influencing electromagnetic radiation in a frequency range between 0.1 and 10 terahertz includes providing a planar modulator having a matrix of at least 10×10 individual, active planar elements. Each planar element has a diameter between 5 ?m and 100 ?m. The planar elements are individually controlled using a central control unit such that each planar element assumes a respective one of at least two states in accordance with the control so as to influence the radiation.

Abstract: The invention relates to a method for the wireless data, transmission between a transmitter and a receiver, the data being modulated as signals onto an electromagnetic carrier wave in the range of 0.1 and 10 terahertz. The carrier wave emitted by the transmitter is concentrated in the direction of the receiver, the transmitter being oriented towards the receiver by means of an automatic adjusting device and the adjusting device using wireless communication between the transmitter and the receiver for said orientation.

Abstract: A method for processing received electromagnetic radiation includes receiving electromagnetic radiation having a plurality of carrier waves in the frequency range between 0.1 and 10 terahertz and having modulated onto the carrier waves information with a signal frequency of less than 50 GHz. The received radiation is filtered with a filter that is tunable in the frequency range from 0.1 to 10 terahertz so as to obtain at least one carrier wave as a terahertz signal. The terahertz signal is provided to a detection circuit that is sensitive to the terahertz signal frequency.

Abstract: A method for producing an electromagnetic carrier wave in the frequency range between 0.1 and 10 terahertz that is suitable for the wireless transmission of data includes generating, by an electromagnetic pump wave, at least two mixing waves with a defined frequency difference, the pump wave being configured to constitute one of the mixing waves; and producing an electromagnetic carrier wave by frequency mixing the mixing waves.

Abstract: A method for the treatment of a crystal, such as a lithium niobate crystal or lithium tantalate crystal, having nonlinear optical properties. The crystal comprises foreign atoms which bring about specific absorption of radiated light. The foreign atoms are transformed into a lower valent state by means of oxidation. Electrons, which are released during oxidation, are discharged from the crystal with the aid of an external power source.

Abstract: Method for preparing a purified crystal for use in an optical component, from an impure crystal having impurities or crystal defects capable of causing a specific absorption of incident light, includes heating the impure crystal to a temperature at which ions in the crystal are mobile and provide conductivity. A part of the crystal is illuminated with an electromagnetic purifying beam having a frequency in or near a visible frequency range so as to optically excite and migrate charges in the crystal, the charges being compensated by a counter-migration of the ions so as to be fixed in place thereafter so as to provide a purified crystal zone. The crystal is cooled to a future operating temperature.

Abstract: Method for treating a nominally pure crystal having non-linear optical properties. The nominally pure crystal contain foreign atoms at a residual concentration of less than 20 ppm so as to provide specific absorption of incident light. The method includes determining, based on testing on a specifically doped reference crystal of same type as the nominally pure crystal, a threshold value. The threshold value is defined by a temperature at which a migration of ions in the nominally pure crystal to the surface of the nominally pure crystal ceases. The foreign atoms are transformed to a higher valance state by a thermally-supported oxidation process including heating the nominally pure crystal at a heating rate that increases by less than 3° C. per minute to a maximum temperature above the threshold value and below a Curie temperature of the nominally pure crystal. An electrical voltage is applied so as to eliminate electrons released during the oxidation process from the nominally pure crystal.

Abstract: In the present invention, a volume holographic optical element is used as a pump coupler. The holographic coupler allows at least one pump wavelength to be coupled into the laser medium. The direction of the pump beam onto the coupler is not co-linear with the direction of the signal beam out of the coupler. The invention further provides the coupling of more than one pump wavelengths using a single holographic coupler element while maintaining the high isolation between pump and signal beam. The invention further provides a narrow-band reflection grating of various efficiencies for the signal beam (as part of the laser cavity).

Abstract: The present invention provides a multi-channel tunable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings or a continuously varying filter frequency imprinted into a filter material, such as Lithium Niobate or glass or polymer. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack. In another embodiment, the gratings are recorded by a phase masking method.

Abstract: A method for the treatment of a crystal, such as a lithium niobate crystal or lithium tantalate crystal, having nonlinear optical properties. The crystal comprises foreign atoms which bring about specific absorption of radiated light. The foreign atoms are transformed into a lower valent state by means of oxidation. Electrons, which are released during oxidation, are discharged from the crystal with the aid of an external power source.

Abstract: The invention relates to a method for desensitizing a crystal exhibiting non-linear optical properties, in particular a lithium niobate or lithium tantalate crystal against damage of exposure to light action (optical damages). The similar type damages are caused by refraction index modifications induced by light. The dark conductivity of the crystal is increased by doping with extrinsic ions.

Abstract: The present invention provides a multi-channel tunable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings imprinted into a filter material, such as Lithium Niobate. In another embodiment, the filter comprises a bank of gratings imprinted on a thin-film filter. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack. In another embodiment, the gratings are recorded by a phase masking method.

Abstract: The present invention provides a multi-channel tunable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings or a continuously varying filter frequency imprinted into a filter material, such as Lithium Niobate or glass or polymer. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack. In another embodiment, the gratings are recorded by a phase masking method.

Abstract: The present invention is a method and apparatus for a rotating, tunable, holographic drop filter connected to a fiber optic source. The filter uses a quasi phase-conjugate optical system for a drop-channel fiber coupling and WDM channels which are introduced to the system. The light from these channels is collimated and passed through a volume phase holographic material so that only one WDM channel is diffracted and the rest pass through the holographic material unaffected. A quasi phase-conjugate diffracted beam is generated by the optical system to reflect the diffracted channel back towards the holographic material. The reflected light is Bragg matched to the holographic material so that it is re-diffracted along a path identical to the original incident light beam. A free-space circulator may be used to direct the diffracted beam to a fiber optic collimator, which is different from the fiber optic collimator of the incident light beam.