Abstract: Gradient index lenses are described that are integrated within a planar optical structure. The gradient index lens is optically coupled to a planar optical waveguide. In some embodiments, the gradient index lens with variation in index-of-refraction n one dimension is within an optical fiber. The optical fiber includes cladding at least along the edges of the central plane of the gradient index lens. Methods for forming the integrated structures are described. Further optical structures involving the gradient index lenses are also described.

Abstract: An optical element such as a beam splitter for interferometer separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers can conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: A polarization control system includes a beam source that generates a first beam component containing light with a first polarization and a first frequency and a second beam component containing light with a second polarization and a second frequency. A polarization state modulator adjusts the polarizations of the components for transmission on a single optical fiber. A detector system measures polarizations of the components when output from the optical fiber and determines how to adjust the polarization state modulator in order to give the first and the second components the desired output polarization states. The beam source can be implemented using a Zeeman-split laser, a laser containing a birefringent element, a pair of phase-locked lasers, and/or a variety of configurations of electro-optic or acousto-optic crystals operated to create or enhance the frequency difference between the beam components.

Abstract: Three dimensional optical structures are described that can have various integrations between optical devices within and between layers of the optical structure. Optical turning elements can provide optical pathways between layers of optical devices. Methods are described that provide for great versatility on contouring optical materials throughout the optical structure. Various new optical devices are enabled by the improved optical processing approaches.

Abstract: A polarization control system includes a light source that generates two light beams with different polarization states and optical frequencies. A polarization state modulator changes the polarization states of the two light beams. Three detector paths generate a first beat signal, a second beat signal, and a third beat signal from the two light beams. An amplitude detector determines the amplitude of the first beat signal at a beat frequency. A phase comparator determines the phase difference between the second and the third beat signals. The system then uses the amplitude and the phase difference to determine how to adjust the polarization state modulator in order to generate the first and the second light beams with the desired polarization states.

Abstract: A polarization control system includes a beam source that generates a first beam component containing light with a first polarization and a first frequency and a second beam component containing light with a second polarization and a second frequency. A polarization state modulator adjusts the polarizations of the components for transmission on a single optical fiber. A detector system measures polarizations of the components when output from the optical fiber and determines how to adjust the polarization state modulator in order to give the first and the second components the desired output polarization states. The beam source can be implemented using a Zeeman-split laser, a laser containing a birefringent element, a pair of phase-locked lasers, and/or a variety of configurations of electro-optic or acousto-optic crystals operated to create or enhance the frequency difference between the beam components.

Abstract: A polarization control system includes a beam source that generates a first beam component containing light with a first polarization and a first frequency and a second beam component containing light with a second polarization and a second frequency. A polarization state modulator adjusts the polarizations of the components for transmission on a single optical fiber. A detector system measures polarizations of the components when output from the optical fiber and determines how to adjust the polarization state modulator in order to give the first and the second components the desired output polarization states. The beam source can be implemented using a Zeeman-split laser, a laser containing a birefringent element, a pair of phase-locked lasers, and/or a variety of configurations of electro-optic or acousto-optic crystals operated to create or enhance the frequency difference between the beam components.

Abstract: An optical element such as a beam splitter for interferometer separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers can conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: An interferometer includes a two-frequency laser and a polarizing beam splitter (PBS) that separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: A polarization control system includes a beam source that generates a first beam component containing light with a first polarization and a first frequency and a second beam component containing light with a second polarization and a second frequency. A polarization state modulator adjusts the polarizations of the components for transmission on a single optical fiber. A detector system measures polarizations of the components when output from the optical fiber and determines how to adjust the polarization state modulator in order to give the first and the second components the desired output polarization states. The beam source can be implemented using a Zeeman-split laser, a laser containing a birefringent element, a pair of phase-locked lasers, and/or a variety of configurations of electro-optic or acousto-optic crystals operated to create or enhance the frequency difference between the beam components.

Abstract: A polarization control system includes a light source that generates two light beams with different polarization states and optical frequencies. A polarization state modulator changes the polarization states of the two light beams. Three detector paths generate a first beat signal, a second beat signal, and a third beat signal from the two light beams. An amplitude detector determines the amplitude of the first beat signal at a beat frequency. A phase comparator determines the phase difference between the second and the third beat signals. The system then uses the amplitude and the phase difference to determine how to adjust the polarization state modulator in order to generate the first and the second light beams with the desired polarization states.

Abstract: An optical element such as a beam splitter for interferometer separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers can conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: An optical element such as a beam splitter for interferometer separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers can conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: A beam source for a heterodyne interferometer generates a beam containing components with different frequencies and respective orthogonal circular polarizations and directs the beam down an isotropic single-mode or few-mode optical fiber. Polarizations of light exiting the optical fiber are converted to orthogonal linear polarizations for use in the interferometer, where the frequency components are separated according to linear polarization. Crosstalk between left-handed and right-handed polarizations in the fiber is low, which permits clean separation of frequency components. A quarter-wave plate or other optical element that converts the polarization in the beam exiting the fiber has a mounting with tilt and roll angle adjustments to adjust to exit polarizations that depend on bends in the fiber. The fiber can have a rigid jacket or fast relaxation time to provide a stable output.

Abstract: A beam source for a heterodyne interferometer generates a beam containing components with different frequencies and respective orthogonal circular polarizations and directs the beam down an isotropic single-mode or few-mode optical fiber. Polarizations of light exiting the optical fiber are converted to orthogonal linear polarizations for use in the interferometer, where the frequency components are separated according to linear polarization. Crosstalk between left-handed and right-handed polarizations in the fiber is low, which permits clean separation of frequency components. A quarter-wave plate or other optical element that converts the polarization in the beam exiting the fiber has a mounting with tilt and roll angle adjustments to adjust to exit polarizations that depend on bends in the fiber. The fiber can have a rigid jacket or fast relaxation time to provide a stable output.

Abstract: An interferometer includes a two-frequency laser and a polarizing beam splitter (PBS) that separates a heterodyne beam from the laser into separate beams having different the frequencies and orthogonal polarizations. Optical fibers conduct the separate beams to a beam combiner for interferometer optics. The PBS and/or the beam combiner can use a coating to reflect one linear polarization and transmit an orthogonal linear polarization. To improve extinction ratios in the PBS or the beam combiner, a yaw angle for an input beam is non-zero and corresponds to a peak in the extinction ratio of a reflected beam.

Abstract: An interferometer includes a two-frequency laser, a polarizing beam splitter that separates a beam from the laser into separate beams, and optical fibers that conduct the separate beams to a beam combiner for interferometer optics. The beam combiner uses a birefringent material to merge desired orthogonal polarization components of two separate beams into a combined beam that is input into the interferometer optics. Components of the two beams that lack the desired polarizations are directed away from the combined beam so that the combined beam contains highly orthogonal polarizations for frequency components.

Abstract: A liquid crystal cell for an image projection apparatus has a liquid crystal layer sandwiched between two conductive layers. The layer surface is divided into one or more regions and one of the sandwiching conductive layers is divided into separate sections each matching a different region. Busbars are bonded on the other of these conductive layers along the edges and boundary lines between adjacent regions (resistors) such that negative and positive writing/erasing can be performed in selected region or regions. By applying one or more current pulses in one or more of these resistors, the corresponding region or regions can be more completely erased and a uniform dark background can be created therein.