Abstract: A reconfigurable polarization rotator is formed of an array of very small liquid crystal (LC) cells (e.g., cells of less than 10 ?m in width, termed “microcells”), referred to hereinafter as “microcells”. Each LC microcell is addressable by a separate electrical voltage input that independently controls the polarization rotation performed by the associated LC microcell. By defining a set of adjacent microcells to be held at the same voltage level, that group may be used to form a polarization rotator window of a proper size for a first fiber array configuration. When a fiber array of a different configuration (say, an array with twice the pitch) is used, a different-sized group of adjacent LC microcells is held at a common voltage level so as to form a reconfigured “window” of a new dimension.

Abstract: A voltage-controlled optical wedge is formed by creating an adjustable voltage gradient along the length of a relatively large-sized LC cell. A pair of bias voltages (AC voltages) are applied at the opposing side terminations of the LC cell, their RMS values selected to create a continuous phase variation along the length of the cell, where a defined phase variation is associated with a specific beam steering angle. Adjustments in the applied bias voltages (specifically, changes in the RMS values of the bias voltages) result in changing the beam steering angle, providing for active, controllable beam steering as a function of time. The LC cell may be configured to provide either a linear or nonlinear continuous phase variation, as preferred for different beam steering applications.

Abstract: A voltage-controlled optical wedge is formed by creating an adjustable voltage gradient along the length of a relatively large-sized LC cell. A pair of bias voltages (AC voltages) are applied at the opposing side terminations of the LC cell, their RMS values selected to create a continuous phase variation along the length of the cell, where a defined phase variation is associated with a specific beam steering angle. Adjustments in the applied bias voltages (specifically, changes in the RMS values of the bias voltages) result in changing the beam steering angle, providing for active, controllable beam steering as a function of time. The LC cell may be configured to provide either a linear or nonlinear continuous phase variation, as preferred for different beam steering applications.

Abstract: A reconfigurable polarization rotator is formed of an array of very small liquid crystal (LC) cells (e.g., cells of less than 10 ?m in width, termed “microcells”), referred to hereinafter as “microcells”. Each LC microcell is addressable by a separate electrical voltage input that independently controls the polarization rotation performed by the associated LC microcell. By defining a set of adjacent microcells to be held at the same voltage level, that group may be used to form a polarization rotator window of a proper size for a first fiber array configuration. When a fiber array of a different configuration (say, an array with twice the pitch) is used, a different-sized group of adjacent LC microcells is held at a common voltage level so as to form a reconfigured “window” of a new dimension.

Abstract: A voltage-controlled optical wedge is formed by creating an adjustable voltage gradient along the length of a relatively large-sized LC cell. A pair of bias voltages (AC voltages) are applied at the opposing side terminations of the LC cell, their RMS values selected to create a continuous phase variation along the length of the cell, where a defined phase variation is associated with a specific beam steering angle. Adjustments in the applied bias voltages (specifically, changes in the RMS values of the bias voltages) result in changing the beam steering angle, providing for active, controllable beam steering as a function of time. The LC cell may be configured to provide either a linear or nonlinear continuous phase variation, as preferred for different beam steering applications.

Abstract: A two-step optimization process is utilized to define an optimal phase profile for a LCoS spatial light modulator. The two-step optimization process first utilizes a nonlinear constrained optimization (NCO) program to determine the specific parameters required to obtain an optimal phase profile (hologram), where the “optimal phase profile” is typically defined as that profile which achieves maximum diffraction efficiency for optical switching. Following this first step, phase scaling (and perhaps an adjustment in the number of pixels per period) is employed to slightly modify the values of the optimal phase profile to effectively suppress crosstalk peaks. If any orders still exhibit an unacceptable level of crosstalk, these orders are then subtracted from the phase profile to create the final design.

Abstract: A two-step optimization process is utilized to define an optimal phase profile for a LCoS spatial light modulator. The two-step optimization process first utilizes a nonlinear constrained optimization (NCO) program to determine the specific parameters required to obtain an optimal phase profile (hologram), where the “optimal phase profile” is typically defined as that profile which achieves maximum diffraction efficiency for optical switching. Following this first step, phase scaling (and perhaps an adjustment in the number of pixels per period) is employed to slightly modify the values of the optimal phase profile to effectively suppress crosstalk peaks. If any orders still exhibit an unacceptable level of crosstalk, these orders are then subtracted from the phase profile to create the final design.

Abstract: An achromatic half wave plate includes a first twisted nematic liquid crystal layer, a second twisted nematic liquid crystal layer, and a uniaxial half wave plate between the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer. In one embodiment the first twisted nematic liquid crystal layer and the second twisted nematic liquid crystal layer have an identical twist angle of 135 degrees. The optic axis at the entrance of the first twisted nematic liquid crystal layer is substantially orthogonal to the optic axis at the exit of the second twisted nematic liquid crystal layer.

Abstract: The invention includes an apparatus for processing an input optical beam. The apparatus has at least one variable optical element to dynamically alter the polarization state of an optical beam to form a polarization-altered optical beam, wherein the polarization-altered optical beam includes elliptical polarization. At least one wave plate operates on the polarization-altered optical beam, each wave plate has a selected retardation, order of retardation, and orientation. A polarization analyzer, operating in conjunction with the at least one variable optical element and wave plate, alters the transmitted amplitude of the polarization-altered optical beam as a function of wavelength, and thereby produces an output optical beam with transmitted amplitude adjusted as a function of wavelength.

Abstract: An apparatus for processing an optical beam has at least one variable optical element to dynamically alter the polarization state of a polarized optical beam to form a polarization-altered optical beam. The polarization-altered optical beam includes elliptical polarization. The at least one variable optical element is a compound birefringent crystal with a designed retardation response to temperature variations. In one embodiment, the compound birefringent crystal has a designed retardation response that is substantially invariant with operating temperature variations. At least one wave plate processes the polarized optical beam. Each wave plate has a selected retardation, order of retardation, and orientation.

Abstract: An apparatus for processing an optical beam has at least one variable optical element to dynamically alter the polarization state of a polarized optical beam to form a polarization-altered optical beam. The polarization-altered optical beam includes elliptical polarization. The at least one variable optical element is a compound birefringent crystal with a designed retardation response to temperature variations. In one embodiment, the compound birefringent crystal has a designed retardation response that is substantially invariant with operating temperature variations. At least one wave plate processes the polarized optical beam. Each wave plate has a selected retardation, order of retardation, and orientation.

Abstract: The invention includes an apparatus for processing an input optical beam. The apparatus has at least one variable optical element to dynamically alter the polarization state of an optical beam to form a polarization-altered optical beam, wherein the polarization-altered optical beam includes elliptical polarization. At least one wave plate operates on the polarization-altered optical beam, each wave plate has a selected retardation, order of retardation, and orientation. A polarization analyzer, operating in conjunction with the at least one variable optical element and wave plate, alters the transmitted amplitude of the polarization-altered optical beam as a function of wavelength, and thereby produces an output optical beam with transmitted amplitude adjusted as a function of wavelength.