526 results about "Single polarization" patented technology

An imaging system, comprising a broadband unpolarized white light source (81), a polarization converter system for converting polarization axes of unpolarized white light into a substantially single polarization axis, to produce a beam of polarized light, a selective polarization filter (82), adapted to selectively rotate a polarization axis of a selected spectral band of light of the with respect to remaining polarized light based on a control signal (119), a polarized beam splitter (84), for separating light having a the substantially single polarization axis from light having a rotated polarization axis, a pair of electro-optic spatial light modulators (86, 89), disposed along a path of light within the spectral band and a path of remaining light outside the spectral band, respectively, and being adapted to modulate an image therein, and a polarized beam splitter (88), for recombining modulated light from the pair of light modulators. In a preferred embodiment, the selective polarization filter (82, 72) is divided into a plurality of regions (70, 71), each adapted to independently and selectively rotate a polarization axis of a selected spectral band of light of the with respect to remaining polarized light.

A method is provided for an equalization strategy for compensating channel distortions in a dual-polarization optical transport system wherein the received signal includes a complex signal of a first transmitted polarization component and a complex signal of a second transmitted polarization component. In a first step, a blind self-recovery mode used a blind adaptation algorithm in calculating and modifying multiple complex equalizer transfer function coefficients to enable recovery of only the complex signal of the first transmitted polarization component. By recovering only a single polarization component in the first step the degenerate case of recovering only a single transmitted signal at both polarization component outputs of an equalizer is prevented. In a second step, equalization is performed in a training mode for calculating and modifying the multiple complex equalizer transfer function coefficients to enable recovery of the complex signals of the first and second transmitted polarization components. In a third step, equalization is performed in a data directed mode for continuing to calculate and modify the multiple complex equalizer transfer function coefficients to ensure continued recovery of the complex signals of the first and second transmitted polarization components. The method is suited for a digital signal processing implementation in a coherent receiver when a modulation scheme used on a transmitted signal is quadriphase-shift keying (QPSK). In other embodiments, the method can be used with modulation schemes such as binary PSK, M-ary PSK where M>4, or Quadrature Amplitude Modulation (QAM).

An alignment target includes periodic patterns on two elements. The periodic patterns are aligned when the two elements are properly aligned. By measuring the two periodic patterns with an incident beam having a single polarization state and detecting the intensity of the resulting polarized light, it can be determined if the two elements are aligned. The same polarization state may be detected as is incident or different polarization states may be used. A reference measurement location may be used that includes a third periodic pattern on the first element and a fourth periodic pattern on the second element, which have a designed in offset, i.e., an offset when there is an offset of a known magnitude when the first and second element are properly aligned. The reference measurement location is similarly measured with a single polarization state.

A laser-based atomic magnetometer (LBAM) apparatus measures magnetic fields, comprising: a plurality of polarization detector cells to detect magnetic fields; a laser source optically coupled to the polarization detector cells; and a signal detector that measures the laser source after being coupled to the polarization detector cells, which may be alkali cells. A single polarization cell may be used for nuclear magnetic resonance (NMR) by prepolarizing the nuclear spins of an analyte, encoding spectroscopic and / or spatial information, and detecting NMR signals from the analyte with a laser-based atomic magnetometer to form NMR spectra and / or magnetic resonance images (MRI). There is no need of a magnetic field or cryogenics in the detection step, as it is detected through the LBAM.

Methods and systems for grating couplers incorporating perturbed waveguides are disclosed and may include in a semiconductor photonics die, communicating optical signals into and / or out of the die utilizing a grating coupler on the die, where the grating coupler comprises perturbed waveguides. The perturbed waveguides may comprise a variable width along their length. The grating coupler may comprise a single polarization grating coupler comprising perturbed waveguides and a non-perturbed grating. The grating coupler may comprise a polarization splitting grating coupler (PSCC) that includes two sets of perturbed waveguides at a non-zero angle, or a plurality of non-linear rows of discrete shapes. The PSCC may comprise discrete scatterers at an intersection of the sets of perturbed waveguides. The grating couplers may be etched in a silicon layer on the semiconductor photonics die or deposited on the semiconductor photonics die. The grating coupler may comprise individual scatterers between the perturbed waveguides.

A communication system uses quantum cryptography for the secure distribution of a key. A single-photon signal is phase-modulated and transmitted over a pair of time-multiplexed transmission paths. With each original single-photon signal in a given one of the transmission paths, a duplicate signal is transmitted. The duplicate is identically modulated and orthogonally polarized. At the receiver, the outputs of the two paths are combined interferometrically. A single polarization-insensitive measurement is derived from the combined contributions of the orthogonally polarized signals.

An optical mixer that, in one embodiment, has a single optical hybrid optically coupled to a single polarization beam splitter. The optical hybrid mixes a polarization-multiplexed optical communication signal and a local-oscillator signal to generate four mixed signals, each corresponding to a different relative phase shift between the communication and local-oscillator signals. The polarization beam splitter separates each of the mixed signals into two polarization components, subsequent processing of which enables an optical receiver employing the optical mixer to recover the data carried by the communication signal.

A novel polarization maintaining optical fiber, which can be used as a high-power polarization maintaining fiber laser or amplifier, is described. Insensitivity of the polarization state to external fiber bending and temperature changes is accomplished by minimizing polarization mode-coupling via reducing stresses inside the fiber core via increasing the fiber diameter. Alternatively, polarization mode-coupling can be minimized by an optimization of the fiber coating to minimize stresses at the interface between the fiber and the coating. As a result insensitivity to polarization mode-coupling is obtained at greatly reduced values of birefringence compared to small-diameter fibers. The fiber is of significant use in any application where polarization stability is important, and will be useful in telecommunications applications in particular for reducing polarization mode dispersion. An implementation in a parabolic pulse-producing fiber laser is also described as one specific high power example.

A method and system for enabling lightpath monitoring in an optical network is disclosed. A single polarization modulator / scrambler introduces a pilot tone signal as an overlay on a plurality of optical signals on a source node and a performance monitoring unit detects the pilot tone signal to enable light path monitoring and identification through the optical network.

An optical fiber, comprising: (i) a rare earth doped silica based elongated core with a first refractive index (n1) with an aspect ratio of 1:5 to 1; (ii) a silica based moat abutting and at least substantially surrounding the core, the moat having a refractive index n2, wherein n2<n1; (iii) a silica based inner cladding surrounding the moat, the inner cladding having a third refractive index (n3), wherein n1>n3; and n3>n2; (iv) a silica based outer cladding surrounding said inner cladding, the outer cladding having a fourth refractive index (n4), such that n4<n3; the optical fiber exhibits single polarization at the operating wavelength band.

A method of producing an active optical waveguide having asymmetric polarization, said method comprising the steps of (a) providing an active optical waveguide (10) comprising: (i) a transverse refractive index profile (21) comprising a guiding region (11), an intermediate region (13), and a non-guiding region (12); (ii) a transverse photorefractive dopant profile (31) comprising a constant or graded photorefractive dopant concentration within at least one of the guiding, non-guiding and intermediate regions, except that the photorefractive dopant is not located solely in the guiding region; and (iii) exhibiting in said guiding region, intermediate region, or both, light guiding modes having different polarizations; and (b) exposing at least a part (10a, 10b) of the active optical waveguide to an effective transverse illumination of light (20) reacting with the photorefractive dopant and modifying said transverse refractive index profile; said part of the active optical waveguide being exposed to a fluence selectively suppressing the propagation of the light guiding modes having different polarizations so that the propagation of one mode is less suppressed than the propagation of the other mode(s). Such an active optical waveguide, single polarization mode optical waveguide lasers and multi-wavelength single polarization mode optical waveguide lasers comprising such an active optical waveguide, methods of their production, and their uses in telecommunications, in spectroscopy, in sensors and in absolute calibrated laser light sources.

A novel polarization maintaining optical fiber, which can be used as a high-power polarization maintaining fiber laser or amplifier, is described. Insensitivity of the polarization state to external fiber bending and temperature changes is accomplished by minimizing polarization mode-coupling via reducing stresses inside the fiber core via increasing the fiber diameter. Alternatively, polarization mode-coupling can be minimized by an optimization of the fiber coating to minimize stresses at the interface between the fiber and the coating. As a result insensitivity to polarization mode-coupling is obtained at greatly reduced values of birefringence compared to small-diameter fibers. The fiber is of significant use in any application where polarization stability is important, and will be useful in telecommunications applications in particular for reducing polarization mode dispersion. An implementation in a parabolic pulse-producing fiber laser is also described as one specific high power example.

An optical transport system configured to transmit at least two phase-conjugated optical variants carrying the same modulated symbols, with the phase-conjugated optical variants in being different from one another in one or more of polarization of light, the time of transmission, spatial localization, optical carrier wavelength, and subcarrier frequency during transmission. The two phase-conjugated optical variants can be generated by a single polarization-diversity transmitter to be orthogonally polarized, and propagate through an optical transmission link with the same wavelength and spatial path. The optical variants are detected and processed at the receiver in a manner that enables coherent summation of the corresponding electrical signals prior to constellation de-mapping. The coherent summation tends to cancel out the deleterious effects of nonlinear distortions imparted on the individual phase-conjugated optical variants in an optical fiber transmission link because said nonlinear distortions tend to be opposite to each other.

Structures and configurations for planar ultrawideband modular antenna arrays. One example of a PUMA array includes an unbalanced RF interface, a lattice of horizontal dipole segments directly fed with the unbalanced RF interface, the lattice being arranged in either a dual-offset dual-polarized configuration or a single-polarization configuration, and a metallic plate capacitively-coupled to the lattice of horizontal dipole segments and pinned to a ground plane with a first plated via.

A laser-based atomic magnetometer (LBAM) apparatus measures magnetic fields, comprising: a plurality of polarization detector cells to detect magnetic fields; a laser source optically coupled to the polarization detector cells; and a signal detector that measures the laser source after being coupled to the polarization detector cells, which may be alkali cells. A single polarization cell may be used for nuclear magnetic resonance (NMR) by prepolarizing the nuclear spins of an analyte, encoding spectroscopic and / or spatial information, and detecting NMR signals from the analyte with a laser-based atomic magnetometer to form NMR spectra and / or magnetic resonance images (MRI). There is no need of a magnetic field or cryogenics in the detection step, as it is detected through the LBAM.

Systems and methods are disclosed for using ellipsometer configurations to measure the partial Mueller matrix and the complete Jones matrix of a system that may be isotropic or anisotropic. In one embodiment two or more signals, which do not necessarily satisfy any symmetry assumptions individually, are combined into a composite signal which satisfies a symmetry assumption. The individual signals are collected at two or more analyzer angles. Symmetry properties of the composite signals allow easy extraction of overlay information for any relative orientation of the incident light beam with respect to a ID grating target, as well as for targets comprising general 2D gratings. Signals of a certain symmetry property also allow measurement of profile asymmetry in a very efficient manner. In another embodiment a measurement methodology is defined to measure only signals which satisfy a symmetry assumption. An optional embodiment comprises a single polarization element serving as polarizer and analyzer. Another optional embodiment uses an analyzing prism to simultaneously collect two polarization components of reflected light.

The present disclosure is a novel design of a polarization based stereoscopic display system that efficiently utilizes the optical energy from three primary color solid state light sources of random polarization, combines the three primary colors into a full color beam of a single polarization state to enable passive separation of the two image channels. The high optical energy efficiency is achieved by splitting each primary color light into two orthogonal polarization states. The single polarization state of the combined full color image beam is achieved by employing a spectrally selective light beam combiner or X-cube. By making the optical configuration of sub-module basically identical and sharing a number of optical components among color and image channels, the size and cost is reduced. By compensating the depolarization effect that is introduced by folding mirror(s), the cross talk between the two displayed stereo images is minimized.

Methods and systems for grating couplers incorporating perturbed waveguides are disclosed and may include in a semiconductor photonics die, communicating optical signals into and / or out of the die utilizing a grating coupler on the die, where the grating coupler comprises perturbed waveguides. The perturbed waveguides may comprise a variable width along their length. The grating coupler may comprise a single polarization grating coupler comprising perturbed waveguides and a non-perturbed grating. The grating coupler may comprise a polarization splitting grating coupler (PSCC) that includes two sets of perturbed waveguides at a non-zero angle, or a plurality of non-linear rows of discrete shapes. The PSCC may comprise discrete scatterers at an intersection of the sets of perturbed waveguides. The grating couplers may be etched in a silicon layer on the semiconductor photonics die or deposited on the semiconductor photonics die. The grating coupler may comprise individual scatterers between the perturbed waveguides.

A highly efficient projection system is provided, including a light source, a color separator, a scrolling unit, a light valve, a projection lens unit, and a polarization conversion system. The color separator separates an incident beam according to color. The scrolling unit includes at least one lens cell and converts a rotation of the lens cell into a rectilinear motion of an area of the lens cell through which light passes so the incident beam is scrolled. The light valve processes a beam transmitted by the color separator and the scrolling unit, according to an image signal and forms a color picture. The projection lens unit magnifies the color picture formed by the light valve and projects the magnified color picture onto a screen. The polarization conversion system is installed between the color separator and the light valve and converts the incident beam into a beam with a single polarization.

The embodiment of the invention relates to the field of communication transmission, and discloses an optical signal transmission processing method, an optical signal sending device and an optical signal transmission system. The optical signal sending device comprises a sending end optical signal generating device, a first polarization controller, a second polarized controller, a first quarternaryphase-shift keying modulator, a second quarternary phase-shift keying modulator and a polarization beam combiner, wherein the sending end optical signal generating device is used for generating an optical signal A and an optical signal B with different wavelengths; the first polarization controller is used for carrying out polarization control for the optical signal A and generating an X polarization optical signal A; the second polarized controller is used for carrying out polarization control for the optical signal B and generating a Y polarization optical signal B; the first quarternary phase-shift keying modulator is used for modulating the X polarization optical signal A; the second quarternary phase-shift keying modulator is used for modulating the Y polarization optical signal B; and the polarization beam combiner is used for combining the modulated X polarization optical signal A and the modulated Y polarization optical signal B into a dual-carrier single-polarization optical signal. The invention enables the nonlinear effect in an optical fiber to be inhabited, enhances the nonlinear tolerance limit and the fiber feeding power of the optical signal transmission system andextends the transmission distance.

The polarization instability inherent in laterally-oxidized VCSELs may be mitigated by employing an appropriately-shaped device aperture, a misoriented substrate, one or more cavities or employing the shaped device aperture together with a misoriented substrate and / or cavities. The laterally-oxidized VCSELs are able to operate in a single polarization mode throughout the entire light output power versus intensity curve. Combining the use of misoriented substrates with a device design that has an asymmetric aperture that reinforces the polarization mode favored by the substrate further improves polarization selectivity. Other device designs, however, can also be combined with substrate misorientation to strengthen polarization selectivity.

An LCD panel employing a novel scheme of systemic light recycling. A single polarization state of light is transmitted from the backlighting structure to section of the LCD panel where both spatial intensity and spectral filtering of the transmitted polarized light simultaneously occurs on a subpixel basis. At each subpixel location, spectral bands of light not transmitted to the display surface during spectral filtering, are reflected without absorption back along the projection axis into the backlighting structure. At a subcomponent level within the LCD panel, spectral components of transmitted polarized light not used at any particular subpixel structure location are effectively reflected either directly or indirectly back into the backlighting structure.

Systems and methods are disclosed for using ellipsometer configurations to measure the partial Mueller matrix and the complete Jones matrix of a system that may be isotropic or anisotropic. In one embodiment two or more signals, which do not necessarily satisfy any symmetry assumptions individually, are combined into a composite signal which satisfies a symmetry assumption. The individual signals are collected at two or more analyzer angles. Symmetry properties of the composite signals allow easy extraction of overlay information for any relative orientation of the incident light beam with respect to a 1D grating target, as well as for targets comprising general 2D gratings. Signals of a certain symmetry property also allow measurement of profile asymmetry in a very efficient manner. In another embodiment a measurement methodology is defined to measure only signals which satisfy a symmetry assumption. An optional embodiment comprises a single polarization element serving as polarizer and analyzer. Another optional embodiment uses an analyzing prism to simultaneously collect two polarization components of reflected light.

A method and system for single laser bidirectional links are disclosed and may include communicating a high speed optical signal from a transmit CMOS photonics chip to a receive CMOS photonics chip and communicating a low-speed optical signal from the receive CMOS photonics chip to the transmit CMOS photonics chip via one or more optical fibers. The optical signals may be coupled to and from the CMOS photonics chips utilizing single-polarization grating couplers. The optical signals may be coupled to and from the CMOS photonics chips utilizing polarization-splitting grating couplers. The optical signals may be amplitude or phase modulated. The optical fibers may comprise single-mode or polarization-maintaining fibers. A polarization of the high-speed optical signal may be configured before communicating it over the single-mode fibers. The low-speed optical signal may be generated by modulating the received high-speed optical signal or from a portion of the received high-speed optical signal.

A planar antenna comprising a signal path for receiving or transmitting a signal, a conductive layer having a slot formed therein positioned to electromagnetically couple with the signal path, a conductive plate parallel to and overlying the slot and spaced therefrom by a dielectric layer, the conductive plate being electrically in contact with the signal path, and one or more patches parallel to and above the conductive plate.

The invention discloses a single-polarization single-mode photonic crystal fiber with high nonlinearity. The cross section of the photonic crystal fiber comprises a fiber core and a cladding. The-cladding is a peripheral region which is the same as the normal photonic crystal fiber and is formed by evenly distributed air holes (2) with the same structure. The fiber core is composed of a substrate material (1) which is arranged on the center of the optical fiber end face as well as four high-ellipticity air holes (3) which are closely arranged, not mutually overlapped and in rectangular distribution. In the photonic crystal fiber, a cut off characteristic of two polarization modes of a basic mode can be adjusted by finely adjusting distance between centers of air holes, which causes one of the polarization modes to be cut off in the applied waveband, thus realizing the wide-bandwidth single polarization transmission. Meanwhile, the air holes (3) suppress the generation of high order mode, which allows the cladding to use a higher air filling rate on the premise of not changing the single-mode transmission characteristic of the optical fiber, therefore the mode area and the confinement loss are reduced. The single-polarization single-mode photonic crystal fiber with the high nonlinearity solves the problem that the high nonlinearity, low confinement loss and wide band single-polarization single-mode characteristic can not be realized at the same time in the existing photonic crystal fiber technology.

This specification discloses a VCSEL (Vertical-Cavity Surface-Emitting Laser) device with single-mode output and optionally single polarization output. This device is given by lateral mode confinement by the PBG (Photonic Band-Gap) effect by shallow etching in a partial VCSEL top mirror. The PBG area encircles a MS-region (Mode-Shaping region), which is characterized by large longitudinal mode losses. The MS-region encircles the LA-region (Light Aperture region), which is characterised by low longitudinal mode losses. The MS-region does not contribute to the lateral mode-confinement to the LA-aperture, and the lateral modes confined by the PBG area. The VCSEL is thus optimized for single fundamental mode operation.

The invention relates to a combined navigation method based on polarization information. The combined navigation method comprises the following steps: firstly, checking astronomical ephemeris according to carrier positions and moments so as to obtain sun position information; secondly, measuring by using a polarization sensor so as to obtain polarization information, and measuring speed information by using a light stream sensor; thirdly, on the basis of polarization and light stream, establishing a filtering measuring model; and finally, estimating navigation error information by using a kalman filter. By adopting the combined navigation method, a linear measuring model based on single-polarization sensor is established, and the model is simple, small in filtering calculation amount, high in precision and applicable to autonomous navigation of the carrier for a relatively long time.

An optical fiber including: (i) a silica based, rare earth doped core having a first index of refraction n1; (ii) a silica based inner cladding surrounding the core and having a second index of refraction n2, such that n1>n2, said inner cladding having a plurality of air holes extending longitudinally through the length of said optical fiber; (iii) a silica based outer cladding surrounding said inner cladding and having a third index of refraction n3, such that n2>n3, wherein said optical fiber supports a single polarization mode within the operating wavelength range.

The invention relates to an ultra-wide band antenna and single-polarized and dual-polarized radiating elements thereof. The dual-polarized radiating element is formed on the basis of orthogonality of two pairs of single-polarized radiating elements, wherein each single-polarized radiating element is used for transmitting and receiving a single polarized signal and comprises a reflecting plate, a pair of element arms and a feed member, the reflecting plate constitutes a reflector of the radiating element, the pair of element arms constitute a half-wave symmetrical dipole, the feed member is fixed on the reflecting plate, and a circuit for feeding the element arms is manufactured on the feed member; and each element arm is connected with the reflecting plate by at least two supporting members so as to maintain the relative positional relationship, and non-conducting media separated capacitive coupling is formed among the supporting members. The radiating elements and the ultra-wide band antenna thereof have simple structure and low manufacturing cost and can obtain good wideband characteristics.