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522 results about "Single polarization" patented technology

Equalization strategy for dual-polarization optical transport system

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).
Owner:CIENA

Single-polarization high power fiber lasers and amplifiers

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.
Owner:IMRA AMERICA

Method for lightpath monitoring in an optical routing network

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.
Owner:AMERICAN TELEPHONE & TELEGRAPH CO

Polarisation asymmetric active optical waveguide, method of its production, and its uses

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.
Owner:KOHERAS +1

Optical signal transmission processing method, sending device and system

ActiveCN101729187AIncrease nonlinear toleranceLong transmission distancePolarisation multiplex systemsElectromagnetic receiversNonlinear toleranceLength wave
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.
Owner:HUAWEI TECH CO LTD

Method and structure for eliminating polarization instability in laterally - oxidized VCSELs

InactiveUS20050158902A1Sufficient polarization selectivityPolarization selectivity can be improvedOptical wave guidanceLaser detailsInstabilityOptoelectronics
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.
Owner:XEROX CORP

Image display panel having a backlighting structure and a single-layer pixelated aray of reflective-type spectral filtering elements where between light is recycled for producing color images with enhanced brightness

InactiveUS6188460B1Avoiding shortcomingHigh color imageTelevision system detailsSolar heating energyColor imageSpectral bands
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.
Owner:REVEO

High non-linear single polarization single-mould photonic crystal fiber

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.
Owner:BEIHANG UNIV
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