321 results about "Optical phase modulator" patented technology

The invention relates to methods for manufacturing semiconductor devices. Processes are disclosed for implementing suspended single crystal silicon nano wires (NWs) using a combination of anisotropic and isotropic etches and spacer creation for sidewall protection. The core dimensions of the NWs are adjustable with the integration sequences: they can be triangular, rectangular, quasi-circular, or an alternative polygonal shape. Depending on the length of the NWs, going from the sub-micron to millimeter range, the NWs may utilize support from anchors to the side, during certain processing steps. By changing the lithographic dimensions of the anchors compared to the NWs, the anchors may be reduced or eliminated during processing. The method covers, among other things, the integration of Gate-All-Around NW (GAA-NW) MOSFETs on a bulk semiconductor. The GAA structure may consist of a silicon core fabricated as specified in the invention, surrounded by any usable gate dielectric, and finally by a gate material, such as polysilicon or metal. The source and drain of the GAA-NW may be connected to the bulk semiconductor to avoid self heating of the device over a wide range of operating conditions. The GAA-NW MOS capacitor can also be used for the integration of a Gate-All-Around optical phase modulator (GAA modulator). The working principle for the optical modulator is modulation of the refractive index by free carrier accumulation or inversion in a MOS capacitive structure, which changes the phase of the propagating light.

An optical beam deflector in which a crosssection of an incident optical (e.g., laser) beam is divided into a first plurality of portions (micro crosssections) by an array of first lenses, a plurality of phases of the optical beam in the first micro crosssections are respectively modified by an array of first optical phase modulators so that a desired phase distribution is realized over the crosssection of the optical beam, and thereafter the crosssection of the optical beam is further divided into a plurality of second micro crosssections, and a plurality of phases of the optical beam in the second micro crosssections are respectively modified by an array of second optical phase modulators. An array of second lenses is provided corresponding to the second optical phase modulators to collect a plurality of portions of the optical beam output from the second optical phase modulators. The first and second optical phase modulators are driven by a driving unit so that the optical beam output from the array of second lenses as a whole is finally directed in a desired direction of deflection or to a desired point.

Described herein is an optical phase modulator (20) including a liquid crystal element (22), disposed between a pair of opposing electrodes (24) and (26). The electrodes (24, 26) are electrically driven for supplying an electric potential V across the liquid crystal element (22) to drive the liquid crystals within element (22) in a predetermined configuration. Electrode (26) includes a grid of individually drivable pixel regions (28), at least some of which include a sub-wavelength grating structure that provides an anisotropic refractive index profile in orthogonal lateral dimensions, thereby creating an effective material form birefringence. Light incident through liquid crystal element (22) and onto electrode (26) is reflected and experiences a relative phase difference of 180° between its constituent orthogonal polarization components, thereby rotating each polarization component into the orthogonal orientation upon reflection.

A small-sized, high-functionality optical pulse compressor capable of generating a low-power, high-repetition-frequency ultrashort pulse train used for ultralast optical communication and photometry, and a simple-structure optical function generator for realizing an arbitrary time waveform. The optical pulse compressor comprises and optical Fourier transform device (F) having an optical phase modulator (9) driven by the repetition-frequency of an input optical pulse train and a dispersive medium (8), for converting the shape of an input optical pulse frequency spectrum into its time waveform, and an optical filter (3) inserted ahead of the optical Fourier transform device (F), for reducing the spectrum width of an input optical pulse, wherein the optical Fourier transform device (F) converts a small-spectrum-width optical pulse output from the optical function generator generates an optical pulse. The optical function generator generates an optical pulse having an arbitrary time waveform by reproducing, as it is, a spectrum waveform-shaped arbitrarily by an optical filter on a time-axis by tch optical Fourier transform device (F).

Described herein is a spatial light modulator (15) for modulating the phase, retardation or polarization state of an incident optical signal propagating in a first dimension. The optical phase modulator (15) includes a liquid crystal material (17) and a pair of electrodes (19 and 21) for supplying an electric potential across the liquid crystal material (17) to drive liquid crystals in a predetermined configuration. Modulator (15) also includes a diffractive optical element (29) disposed adjacent a first electrode (19). Element (29) includes a first array of diffractive elements (31) formed of a first material having a first refractive index and extending in a second dimension substantially perpendicular to the first dimension. Elements (31) are at least partially surrounded by a second material (33) formed of a lower refractive index.

In an optical multilevel transmitter (210), a polar representation of an optical multilevel signal (r, φ) is generated by a polar coordinate multilevel signal generation circuit (212), input to an optical amplitude modulator (211) and a polar coordinate type optical phase modulator (201), and output as an optical multilevel modulated signal (213). The polar coordinate type optical phase modulator (201) generates an optical phase rotation proportional to an input voltage, so the modulation distortion of the electric signal is transferred in a linear form to the optical phases of the optical multilevel modulated signal (213). In an optical multilevel receiver (219), a received signal is input to two sets of optical delay detectors (133) and balance receivers (134) and directly demodulated, and a differential phase Δφ for the received signal is calculated by arctangent computation from the output signal. In a phase adaptive equalizer (205), the modulation distortion of the phase is removed by adaptive equalization of the differential phase Δφ. By separately receiving the amplitude components and combining them, the modulation distortion is removed and highly sensitive optical multilevel transmission is achieved.

The invention discloses an all-fiber current transformer and a method thereof, aiming to overcome the defects that a traditional electromagnetic current transformer is easily subjected to electromagnetic interference and has complicated insulation structure, magnetic saturation existence and the like. The technical scheme of the invention comprises the following steps of: demodulating light output by a light source into X-axis polarized light and Y-axis polarized light by a Y-branch integrated optical phase modulator; converting into sinistral circular polarized light and dextral circular polarized light in a lambda/4 retarder; generating a magnetic field by a current in a lead due to the faraday effect; returning the two beams carrying faraday effect phase information to the Y-branch integrated optical phase modulator to intervene when beams in optical fiber is transmitted around the lead; and enabling an interference result to enter a subsequent treatment system from the optical fiber coupler to acquire the faraday effect phase information at the measuring point. The invention avoids the hidden danger of ferromagnetic resonance and magnetic saturation by adopting the optical fiber as a sensing medium and has a series of advantages of high detection accuracy, good environmental suitability, and the like.

Provided is an optical phase modulating method and apparatus for a quantum key distribution. When an optical phase modulator is arranged outside an optical interferometer, a configuration of the optical interferometer may be simplified, and an extension of an optical path caused by the optical phase modulator, instability and an insertion loss increased in the optical interferometer, and the like, may be overcome. An output feature may be improved by adjusting an applied voltage of the optical phase modulator arranged outside the optical interferometer.

The invention discloses a device for compensating a non-linear damage of optical fiber, belongs to an optical fiber communication device, solves the problem of limitation on transmission speed rate or higher complexity of the conventional restraint device, and guarantees the transmission speed rate of an optical fiber system during compensation of the non-linear damage of the optical fiber. The device comprises an arbitrary waveform generator, a driving amplifier, a first electro-optical phase modulator, a dispersion medium and a second electro-optical phase modulator, wherein a clock signal is input to a trigger end of the arbitrary waveform generator; the arbitrary waveform generator outputs a periodic parabola type waveform signal, and the periodic parabola type waveform signal is amplified by using the driving amplifier into an electric driving signal and sent to driving ends of the first electro-optical phase modulator and the second electro-optical phase modulator at the same time; an optical transmitter outputs a data signal to an input end of the first electro-optical phase modulator; and an output end of the second electro-optical phase modulator is connected with an optical fiber link. The invention has the advantages that: an adopted optical device is simple; the bit error rate of signal receiving reaches 10<-7> to 10<-9>; optical power cost is reduced by about 3 dB; and the device is applicable to a long-distance high-capacity and ultra-high-speed optical fiber communication system of all kinds of modulation formats and transmission speed rate.

A stray-light tolerant LIDAR measurement system. The system comprises an interferometer assembly having a continuous-wave laser source, a photodetection arrangement and optical components. The laser source comprises a laser-light-generating component, a downstream optical phase modulator and a control unit connected to the modulator to deliver a control signal corresponding to a pseudo-noise signal defined by a predetermined phase function. The interferometer assembly comprises an evaluation unit which is coupled to the interferometric photodetector assembly to detect the detector signals of same and to determine the presence and/or movement of particles and/or objects from the detector signals wherein, in the case of two wavelengths emitted from the laser light generating components, the detector signals are detected separately in two wavelength regions, and the phase function has a predetermined step-like time course and the evaluation unit scans the detector signals in synchrony with the timing of the steps of the phase function.

A coherent optical link includes a laser master oscillator operative to generate an amplitude- and phase-stable narrow linewidth optical carrier, a first programmable read-only memory (PROM) having an input for receiving and encoding an M-ary data word, a first digital-to-analog (D/A) converter operative to obtain the amplitude-encoded M-ary data word and output a corresponding analog signal, a Mach-Zehnder intensity modulator that obtains the analog signal and intensity-modulates the carrier based on the analog signal, an optical phase modulator having an input, and an optical waveguide that connects the Mach-Zehnder intensity modulator to the input of the optical phase modulator. The Mach-Zehnder intensity modulator and optical phase modulator may be formed into a single package. A modulation method includes modulating an intensity of an optical signal using a Mach-Zehnder intensity modulator, and then modulating the phase of the intensity-modulated optical signal.

The invention provides a new method used for liquid crystal optical phase modulator phase detection. A laser interferometer system is a main detection circuit for the method, the method comprises a laser device, a polarizer, a filter, the laser interferometer system and a digital camera. Lasers sent by the laser device become linearly polarized lights after passing a polarized film, then the filter enables laser emergent lights to become more equal, the lasers are divided into two ways, one way lasers are modulated by a liquid crystal optical phase modulator prepared to be tested, and the digital camera is used for collecting multiframe phase interference images. An interframe intensity correlation (IIC) matrix figuring interference strip images obtains phase changes of each frame interference image through least-squares iteration. The method has the advantages of being simple in a measuring system, low in requirements for phases and interference images, and high in accuracy.

The invention brings forward a fiber current sensor. The fiber current sensor comprises an optical path unit and an FP cavity which are connected through a polarization maintaining fiber. A quarter wave-plate is connected between the polarization-maintaining fiber and the FP cavity; the optical path unit comprises a light source, an optical circulator, a fiber polarizer and an optical phase modulator which are successively connected; the optical circulator is also connected with a signal processing unit through a photoelectric detector; the FP cavity comprises a polarization-maintaining coupler, a first Faraday rotating mirror, a second Faraday rotating mirror, and a sensing fiber for connecting with a current lead to be detected; one end of the sensing fiber is connected with the first Faraday rotating mirror; the other end of the sensing fiber is connected with one port at one side of the polarization-maintaining coupler; and two ports at the other side of the polarization-maintaining coupler are respectively connected with the second Faraday rotating mirror and the quarter wave-plate. The sensor provided by the invention can improve the precision of current measurement, especially for the measurement of low currents, so that a feasible method is provided for current measuring engineering of the fiber current sensor.

Methods and systems for a low-parasitic silicon high-speed phase modulator are disclosed and may include fabricating an optical phase modulator that comprises a PN junction waveguide formed in a silicon layer, wherein the silicon layer may be on an oxide layer and the oxide layer may be on a silicon substrate. The PN junction waveguide may have p-doped and n-doped regions on opposite sides along a length of the PN junction waveguide, and portions of the p-doped and n-doped regions may be removed. Contacts may be formed on remaining portions of the p-doped and n-doped regions. Portions of the p-doped and n-doped regions may be removed symmetrically about the PN junction waveguide. Portions of the p-doped and n-doped regions may be removed in a staggered fashion along the length of the PN junction waveguide. Etch transition features may be removed along the p-doped and n-doped regions.

An optical phase modulator includes an input source that is configured to receive a light source. There is an output operative to provide a phase modulated output signal based on the received light source. There is a first optical coupler configured to split the light source into a first optical path of a Mach Zehnder Interferometer (MZI) and a second optical path of the MZI. A static phase shifter is configured to provide a static phase shift to the first optical path. There is a phase modulator in the second optical path. There is a second optical coupler configured to combine the first optical path and the second optical path. The first and second optical couplers are tuned such that the phase modulated optical signal at the output provides a substantially constant amplitude that is independent of a change in loss introduced by the phase modulator.

The invention relates to an optical-fiber wireless system for full-duplex communication, which consists of a central station and a base station, wherein the central station and the base station are connected through an optical-fiber transmission links; the central station generates subcarrier signals by mixing baseband signals with radio frequency sine-wave signals, generates optical double-sideband differential phase-shift keying signals through the modulation of an optical phase modulator, performs power amplification, and then transmits the signals to the base station; the base station separates the signals transmitted by the central station; the signals are divided into an upper way and a lower way through an optical splitter; the upper way generates carrier-suppressed differential phase-shift keying optical-carried millimeter waves which are converted into downlink millimeter wave signals through photoelectric conversion and then sent to wireless terminals through antennas; the lower way generates reference local oscillator signals through photoelectric conversion, mixes the reference local oscillator signals with uplink millimeter wave signals, and generates uplink baseband signals through down conversion; and central carrier waves are re-modulated by the uplink baseband signals and then transmitted back to the central station. The system has the advantages of simplifying generation devices for optical-carried millimeter waves and reducing cost, along with simple flexible structure, strong extensibility, more compact structure and easiness for integration.

A device used for generating QPSK millimeter wave of radio frequency optical fiber transmission system consists of semiconductor laser of central station, polarization controller, optical phase modulator, optical comb fiber, optical QPSK modulator, optical branching unit/combining unit, optical detector of base station, narrow band band-pass filter, millimeter wave amplifier and millimeter wave antenna. Its optical modulating method for obtaining QPSK modulated millimeter wave signal is also disclosed.

The invention relates to the field of hyperspectral imager technology, in particular to a hyperspectral full polarization imager based on acousto-optic filtering and electro-optical phase modulation. The hyperspectral full polarization imager is an imaging device combining hyperspectral imaging and full polarization imaging, and relates to a method for simultaneous detection and acquisition of the space, spectral and polarization information of an observed object. The hyperspectral full polarization imager is based on an acousto-optic tunable filter for splitting and a DKDP longitudinal electro-optical phase modulator for polarization detection; and comprises a front imaging lens used for collection, collimation and contraction of radiation, reflection, scattering and transmission light of the object under test and primary imaging to an AOTF; DKDP longitudinal electro-optical phase modulators for phase modulation; the AOTF for filtering and polarization detection; a light shielding plate for shielding 0-level and +1-level diffracted light through the AOTF; a secondary imaging conduction lens for secondary imaging of -1-level diffracted light to a planar array imaging CCD; and a control computer. The invention is mainly used in the field of a hyperspectral imager.

The invention discloses a liquid crystal compound with a high birefringence and a wide nematic phase temperature interval and a liquid crystal composition comprising the liquid crystal compound. The structure of the liquid crystal compound is shown in a general formula I in the Specification. The liquid crystal composition comprises a compound shown as the general formula I, 5-75 percent of a compound shown as a general formula II, 5-25 percent of a compound shown as a general formula III and 5-60 percent of a compound shown as a general formula IV, wherein the content of the compound shown as the general formula I is less than or equal to 55 percent and is not zero. The liquid crystal compound has the advantages of low melting point, high clearing point, high birefringence and high low-temperature intermiscibility. The liquid crystal composition comprising the liquid crystal compound has the wide nematic phase temperature interval and the high birefringence, and is applicable to the fields of 3D (three-dimensional) displays, optical phase modulators, infrared detectors and the like. In the general formulae I, II, III and IV, R1 to R4 are straight-chain paraffin of which the carbon number is 1-9, X1 to X9 are -F or -H, and at least one of the X1 to the X9 is -F.