Abstract: It is aimed to provide a phase modulation apparatus that realizes high-precision phase modulation in high-speed phase modulation of dual optical pulses. A phase modulator 105 included in the phase modulation apparatus, when a dual optical pulse with a time difference composed of a signal optical pulse SP and a reference optical pulse RP passes therethrough, phase-modulates this dual optical pulse in proportion to an applied voltage of an electrical pulse. As a result, a phase-modulated SP? and a phase-modulated RP? are output. A modulation signal generator 106 outputs an electrical pulse of a predetermined bias at an input timing of a trigger signal, according to an input of a four-valued data signal, for example. The modulation signal generator 106 outputs, for one input of the trigger signal, a dual electrical pulse having a time difference and having opposite polarities.

Abstract: Techniques, devices and systems based on optical receivers with controllable transfer function bandwidth and gain imbalance.

Abstract: An adaptive optics system comprises a spatial light modulator, a beamsplitter, a pixelated spatial phase shifter, a beam combiner, an imaging device, and a processor. The spatial light modulator can modulate an incoming beam with an aberrated wavefront. The beamsplitter can receive the modulated beam and divide the modulated beam into a first beam and a second beam. The pixelated spatial phase shifter can spatially phase shift the second beam by at least two phases. The beam combiner can interfere the spatially phase shifted second beam with the first beam to form at least two interferograms on the imaging device, which can capture an image of the at least two interferograms in a single frame. The processor can determine the aberrated wavefront based on the at least two interferograms and provide one or more control signals to the spatial light modulator to mitigate aberrations in the aberrated wavefront.

Abstract: Speckle reduction apparatus includes a radiation path and a mask arranged within the radiation path. The mask includes an array of electrically controllable cells configured to form a pattern on the mask that varies with time. The speckle reduction mask includes a first linear array including first parallel lines arranged to change the phase of incident radiation, and a second linear array including second parallel lines arranged to change the phase of incident radiation and further arranged such that cells are formed at the intersections of the first parallel lines and the second parallel lines. The speckle reduction mask includes a N1×N2 array of cells, A, formed according to: ATA=??k,l, where AT is the transpose of A, ? is a real and positive constant, dk,l is Kronecker delta and N1?N2.

Abstract: A device that provides light beam switching, agile steering of the light beam over a range of angles, and generation of arbitrary wavefront shapes with high spatial and temporal resolution. The agile device can include a volume diffractive structure comprising Bragg planes having one refractive index and the Bragg planes separated by regions containing an active optical medium. Electrodes (which may be the Bragg planes themselves, or may be arrayed adjacent to the active optical medium) are used to control the electric field intensity and direction across the structure, and thereby control the diffraction efficiency of the structure and the local phase delay imposed on a diffracted wavefront. Means are provided for addressing the many thousands of electrodes required for precise and rapid wavefront control. Applications include free-space atmospheric optical communications, near-eye displays, direct-view 3D displays, optical switching, and a host of other applications.

Abstract: A crystallization apparatus includes a light modulation element, and an image forming optical system that forms a light intensity distribution set based on light transmitted through the light modulation element on an irradiation surface. The crystallization apparatus irradiates a non-single crystal semiconductor film with light having the light intensity distribution to generate a crystallized semiconductor film. A curvature radius of at least one isointensity line of a light intensity substantially varies along the isointensity line in the light intensity distribution on the irradiation surface, and a curvature radius of at least a part of the isointensity line has a minimum value of 0.3 ?m or below.

Abstract: An actuation system for at least two mobile elements with dynamically compensated and opposite relative motions, without disturbance of the elements fixed in the same rigid structure as it, and resistant to exterior loadings, in the case of a translational motion of the mobile elements, includes, in a rigid structure, at least one linear actuator linked to a motion transmission device with four rigid arms, articulated at their ends and forming a lozenge, of which each of two first opposite vertices is linked to a corresponding mobile element, and whose other two opposite vertices have a single translational degree of freedom.

Abstract: A laser is placed inside the Mach-Zehnder interferometer and the output from opposite ends of the laser are fed directly into the opposite arms of the Mach-Zehnder interferometer. If the output from opposite sides of the laser are equal in amplitude and wavelength, then when the outputs are recombined at the output of the modulator the intensity is dependent on the relative phase of the light in the two arms of the Mach-Zehnder, just as in a normal Mach-Zehnder modulator. Thus by modulating the phase of one or both arms of the modulator, an intensity modulated source is created. This reduces the overall size of the device, and may ensure that all of the output power from the laser is utilized.

Abstract: Apparatus for combining laser radiation (1) 5 which apparatus comprises a seed laser (2), a splitter (3), a plurality of amplifier chains (4), a reference amplifier chain (7), detection means (5). demodulator means (6), and phase control means (12), wherein each of the amplifier chains (4) comprises at least one optical amplifier (11), optical radiation (17) emitted from the seed laser (2) is split into the plurality of amplifier chains (4) by the splitter (3).

Abstract: Provided is an optical device with improved phase shift and propagation loss of light without decreasing the dynamic characteristics of the optical device. The optical device includes a first semiconductor layer which is doped with a first type of conductive impurities and has a uniform thickness; a gate insulating layer which has a shape and is formed on a portion of the first semiconductor layer and has a thin center portion; and a second semiconductor layer which covers an upper surface of the gate insulating layer and is doped with a second type of conductive impurities opposite to the first type of conductive type impurities.

Abstract: Laser systems and methods for providing an output light beam having a target spatial pattern are provided. A light generating module generates an input light beam, whose spectral profile is then tailored by imposing thereon a controllable phase modulation. The obtained spectrally tailored light beam is dispersed, using at least one spatially-dispersive element to provide an output light beam having a spatial profile which is a function of the spectral profile of the spectrally tailored light beam, The phase modulation is selected in view of the spectral profile of the input light beam and of the dispersion characteristics of the at least one spatially-dispersive element so that the spatial pattern of the output light beam matches the target spatial pattern therefor.

Abstract: The invention describes a modulator for the quadrature modulation of an optical carrier signal with an I- and a Q-portion, where a first optical multimode interferometer (MMI) splits the optical carrier signal into four branches and that in pairs of branches the I-portion and the Q-portion respectively is modulated with a Mach-Zehnder-Structure and a second optical multimode interferometer (MMI) combines the modulated I-portion and Q-portion again to one quadrature modulated optical output signal (OS).

Abstract: An optical modulator includes an optical modulation substrate, an electrical length adjusting substrate, a package containing the substrates, and a plurality of input ports for inputting high frequency electrical signals. The optical modulation substrate includes a substrate body made of an electro-optic material, a ground electrode and a plurality of signal electrodes provided on the substrate body, optical waveguides propagating lights interacting with the signal electrodes, respectively, and electrode input ports inputting the high frequency electrical signals into the signal electrodes, respectively. The signal electrode includes an interacting part, an input end part provided between the electrode input port and interacting part, and a terminal part. The electrical length adjusting substrate includes conductive lines connected to the input ports for inputting the high frequency electrical signals, respectively.

Abstract: In a radio frequency (RF)-photonic arbitrary waveform generator (AWG), an optical carrier signal is phase-modulated using an arbitrary waveform optical phase generator (AWPOG), which may include, e.g., sequential optical phase modulators. The phase-modulated optical signal is combined with a version of the optical carrier signal to yield an optical waveform, whose amplitude varies with a phase shift introduced by the AWPOG to the optical carrier signal. By manipulating electrical inputs to the AWPOG which control the phase shift, the optical waveform can be arbitrary shaped. The optical waveform may then be converted to an electrical waveform having a radio frequency.

Abstract: An optical path is configured to propagate an input optical signal. A plurality of electrodes are configured to produce a plurality of discrete phase shifts on the optical signal. An output optical signal is phase-shifted with respect to the input optical signal by a sum of the plurality of discrete phase shifts.

Abstract: A system and method for locking the relative phase of multiple coherent optical signals, which compensates for optical phase changes induced by vibration or thermal changes in the environment.

Abstract: A digital phase modulator for a fiber-optic measurement device. A predetermined total number of electrodes of different lengths are arranged in parallel and on both sides of a light guidance path in or on an optical substrate. The electrodes are arranged in two or more triples along the light guidance path. In each case, two electrodes of successive length within a triple have the same length ratio with respect to one another. Such length ratio is chosen, in particular, to be ?=1.618. The electrode lengths of this triple are chosen such that the smallest step widths of the output value range of the phase modulator can be formed by subtraction between the values of at least two larger electrodes. This allows the resolution of the phase modulator to be increased from 9 bits to 11 bits without change in chip size.

Abstract: A system comprises an optical processor comprising a sideband generator, an optical filter, and a phase-shift-keying (PSK) modulator, wherein: the sideband generator generates optical frequency sidebands about a carrier frequency of an optical signal; the optical filter discriminates between the optical frequency sidebands and the optical carrier frequency such that optical sidebands of interest can be used to generate an optical millimeter-wave signal; the PSK modulator comprises an optical splitter, an optical phase delay unit, two or more optical gates, and an optical combiner; the optical splitter divides the optical millimeter-wave signal into two or more intermediate signals; the optical phase delay unit delays one or more of the intermediate signals to create distinct phase relationship between them; the optical gates modulate each intermediate signal individually, based on a control input; and the optical combiner combines the gated intermediate signals into a single, PSK-modulated optical millimeter-

Abstract: Laser scanner projection systems that reduce the appearance of speckle in a scanned laser image are provided. The laser projection system includes a visible light source having at least one laser, a scanning element and a system controller. The system controller is programmed to generate a scanned laser image. The system further includes a first lens that focuses a scanned output beam onto an intermediate image and a second lens that projects the intermediate image onto a projection surface. A periodic phase mask having a period that is approximately equal to or greater than the beam waist diameter of the scanned output beam is positioned at the intermediate laser image. The period of the periodic phase mask is such that the projection of the scanned output beam jumps progressively from pixel to pixel, thereby reducing speckle contrast in the scanned laser image.

Abstract: Provided is an electro-optic device. Sine the electro-optic device includes a plurality of first conductive type semiconductor layers and a plurality of depletion layers formed by a third semiconductor disposed between the plurality of first conductive type semiconductor layers, an electro-optic device optimized for a high speed and low power consumption can be provided.

Abstract: According to particular embodiments, reducing cross-phase modulation includes sending instructions to a phase modulation array comprising channel pixel sets that modulate phases of channels. The channel pixel sets comprise a first channel pixel set that modulates a first phase of a first channel and a second channel pixel set that modulates a second phase of a second channel that uses a phase modulation format. The first channel pixel set is instructed to modulate the first phase at a first constant phase. The second channel pixel set is instructed to modulate the second phase at a second constant phase different from the first constant phase in order to create a group delay between the first channel and the second channel.

Abstract: A system and method for producing an 8-QAM-modulated signal are disclosed. The methodology, in an exemplary expedient, generally comprises splitting light from a CW laser into two parts; modulating the first part with a first signal and modulating the second part with a second signal; phase shifting the modulated second part by about ?/4; combining the modulated first part with the phase shifted and modulated second part to produce a four-level modulated signal; and phase modulating the four-level modulated signal with a third signal with a phase modulation of (0, ?/2). Several variations of this method are described herein.

Abstract: A display system is based on a linear array phase modulator and a phase edge discriminator optical system.

Abstract: A display system is based on a linear array phase modulator and a phase edge discriminator optical system.

Abstract: An optical modulation device includes: an optical splitter for splitting input light into a first input beam and a second input beam; an optical intensity modulator for modulating the intensity of the first input beam in response to a modulating signal; a variable optical phase shifter for shifting the phase of the second input beam; and an optical combiner for combining an output beam of the optical intensity modulator and an output beam of the variable optical phase shifter into a combined beam and outputting the combined beam. The amount of phase shift produced by the variable optical phase shifter is externally controlled.

Abstract: The optical modulator branches an input light into (2×N) lights in an optical branching section, and then phase modulates each of the branched lights in (2×N) phase modulating sections, and couples the phase modulated lights in an optical coupling section and generates a quadrature amplitude modulated (QAM) signal light having a 4N value. At this time, a relative difference of optical phases of the phase modulated lights is variably adjusted by an optical phase adjusting section. Moreover, a power ratio of the phase modulated lights is variably adjusted with an optical power adjusting section. As a result, it is possible to output 4N QAM signal light, with good signal quality.

Abstract: An electro-optic device is provided. The electro-optic device includes a junction layer disposed between a first conductivity type semiconductor layer and a second conductivity type semiconductor layer to which a reverse vias voltage is applied. The first conductivity type semiconductor layer and the second conductivity type semiconductor layer have an about 2 to 4-time doping concentration difference therebetween, thus making it possible to provide the electro-optic device optimized for high speed, low power consumption and high integration.

Abstract: A modulation system and a method for generating a return-to-zero (RZ) optical data signal are provided. The modulation system comprises a Mach-Zehnder (MZ) modulator and a drive circuit, which includes a logic XOR gate and a differential amplifier. The logic XOR gate applies a logic XOR operation to a non-return-to-zero (NRZ) electrical data signal and an inverse of an electrical clock signal to generate an electrical intermediate signal. The differential amplifier differentially amplifies the electrical intermediate signal and an inverse of the NRZ electrical data signal to generate an RZ electrical drive signal. The drive circuit drives the MZ modulator with the RZ electrical drive signal to generate the RZ optical data signal.

Abstract: To take out monitor light unaffected by a multilevel optical phase-modulated component. For the purpose, a phase-shift unit that controls phases of plural (n, n is an integral number equal to or greater than 2) input lights, plural (n, n is an integral number equal to or greater than 2) phase modulating units that respectively phase-modulate the input lights from the phase-shift units, a first coupling unit that couples and outputs the phase-modulated lights from the plural phase modulating units as multilevel optical phase-modulated signal light, and a second coupling unit that couples and outputs non-phase-modulated lights from the plural phase modulating units as coupled light are provided.

Abstract: The present invention provides an optical power level discriminating device and method for discriminating optical power levels. The optical discriminating device includes a splitter for receiving an optical signal having first and second signal states, and splitting the received optical signal into a first and a second branch optical signal. A first optical fiber for transporting the first branch optical signal is provided that is made of a material having a high non-linear refractive index providing a different non-linear phase shift to the first and second signal states of the first branch optical signal. A second optical fiber is provided for transporting the second branch optical signal with little or no non-linear effect. The discriminating device also includes a combiner for combining the first branch optical signal and second branch optical signal to produce an output optical signal.

Abstract: An optical signal transmitter of direct modulation, a method for transmitting optical signals, and an optical network are provided. The optical signal transmitter includes a laser diode operating at a bias current above a lasing threshold of the laser diode; a modulating device applies a modulation signal to the diode to produce a first output optical signal having first and second signal power levels; and a power level discriminator. The power level discriminator, from the received first output optical signal, generates a second output signal of significantly improved extinction ratio by reducing power of one of the first and second signal power levels of the first output optical signal.

Abstract: An integrated semiconductor optical device and an optical module capable of the high-speed and large-capacity optical transmission are provided. In an integrated semiconductor optical device in which a plurality of optical devices buried with semi-insulating semiconductor materials are integrated on the same semiconductor substrate and an optical module using the integrated semiconductor optical device, configurations (material and electrical characteristics) of the buried layers are made different for each of the optical devices.

Abstract: A directly modulated spatial light modulator (DM-SLM) may be formed using a semiconductor optical amplifier. The directly modulated spatial light modulator may also be formed with a vertical cavity surface emitting laser having an output side; and an anti-reflection coating located on the output side.

Abstract: The present invention provides a photosensor that uses a phase modulation technique for optical detection and conducts a highly accurate measurement. The photosensor uses a phase change difference of light propagated through a polarization preserving fiber with respect to tensile stress and employs proper polarization preserving fibers for a phase modulator 10, light-transmitting polarization preserving fiber 23, and coil-shaped polarization preserving fiber 30, to achieve a highly accurate measurement.

Abstract: A display system is based on a linear array phase modulator and a phase edge discriminator optical system.

Abstract: The present invention is to provide an optical modulating system for generating a signal of a frequency (f0+2fm) and a signal of a frequency (f0?2fm) and suppressing a signal of a frequency (f0) by a DSB-SC modulator. A fourth harmonic generating system for solving the above problem comprises a first DSB-SC modulator (2) a second DSB-SC modulator (3) and a signal control section (5) for controlling a modulating signal from a signal source (4) for generating modulating signals applied to the first and second DSB-SC modulators (2,3) so that a lower side-band signal (f0) generated by modulating the upper side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) and an upper side-band signal (f0) generated by modulating the lower side-band signal of the DSB-SC modulator (2) by the DSB-SC modulator (3) cancel each other.

Abstract: A delay interferometer and a demodulator including the delay interferometer and a balanced photodetector are provided. A half mirror splits an optical signal into first and second split beams of light which travel on first and second optical paths, respectively. A first reflector being disposed on the first optical path reflects the first split beam of light toward the half mirror. The second reflector being disposed on the second optical path reflects the second split beam of light toward the half mirror. At least one phase compensator being disposed between the half mirror and at least one of the first and second reflectors includes a medium that exhibits thermooptic effect and has temperature dependency of refractive index. The half mirror couples the first and second split beams of light to generate at least first and second coupled beams of light.

Abstract: Systems and methods for compensating for nonlinear phase shift accumulation in an optical ring resonator. An example method includes sending a first beam in a clockwise direction around the optical ring resonator and sending a second beam in a counterclockwise direction around the optical ring resonator. Then, nonlinear phase shift accumulation of the first and second beams is compensated for within the optical ring resonator. Compensating includes creating a negative Kerr effect phase shift for each beam based on an estimate of accumulated positive Kerr effect.

Abstract: A holographic data storage system that includes a write head that includes a pixellated spatial light modulator and a separate or integral phase mask that varies the phase depending on the location in the phase mask that light passes through. The phase variation can be changed over time in a random, pseudo-random, or predetermined fashion. The spatial light modulator and phase mask can be implemented in a liquid crystal SLM (nematic, ferroeleletric, or other), in a DMD SLM, in a magneto-optical SLM, or in any other suitable manner.

Abstract: System and method for effectuating substantially uniform modulation of unpolarized light. Unpolarized light is split into two beams, each beam comprising a different orthogonal mode. The mode of one beam is changed and then the beam is modulated. The other beam is modulated and then its mode is changed. The two modulated beams are combined to form a modulated multi-mode signal.

Abstract: Various embodiments of the present invention are directed to external, electronically controllable, negative index material-based modulators. In one aspect, an external modulator comprises a negative index material in electronic communication with an electronic signal source. The negative index material receives an electronic signal encoding data from the electronic signal source and an unmodulated carrier wave from an electromagnetic radiation source. Magnitude variations in the electronic signal produce corresponding effective refractive index changes in the negative index material encoding the data in the amplitude and/or phase of the carrier wave to produce an electromagnetic signal.

Abstract: Various embodiments of the present invention are directed to scrambling-descrambling systems for encrypting and decrypting electromagnetic signals transmitted in optical and wireless networks. In one aspect, a system (1302) for scrambling electromagnetic signals comprises a first electronically reconfigurable electro-optical material (1402) positioned to receive a beam of electromagnetic radiation including one or more electromagnetic signals encoding data. The beam is transmitted through the electro-optical material (1402) and a two-dimensional speckled pattern (1410) is introduced into the cross-section of the beam such that data encoded in the one or more electromagnetic signals is scrambled.

Abstract: A light irradiation apparatus includes a light modulation element which modulates a phase of an incident light beam to obtain a V-shaped light intensity distribution having a bottom portion of a minimum light intensity, and an image formation optical system which applies the modulated light beam from the light modulation element to an irradiation target surface in such a manner that the V-shaped light intensity distribution is provided on the irradiation target surface. The light modulation element has such a complex amplitude transmittance distribution that a secondary derivative of a phase value of a complex amplitude distribution becomes substantially zero at the bottom portion of the V-shaped light intensity distribution in an image space of the image formation optical system.

Abstract: To provide an image display apparatus in which provision of a mechanical mechanism is not required for reducing an effect of a speckle noise that is generated when a coherent light is used as a light source and a noise can be suppressed. An image display apparatus (1) changes phase of a light emitted from a light source device (a laser light source device (10) including laser light sources (10a to 10c) for each of R, G, and B colors is shown as a sample) at high speed by a phase change portion including an electro-optical crystal (phase change portions (12a to 12c) corresponding to each laser are shown as a sample). Therefore, because an interference pattern on a screen (16) changes at high speed and it is averaged by the human eye, the speckle noise can be reduced.

Abstract: An optical tweezers controlling device including a light source, an objective lens and a focus adjusting unit is provided. The focus adjusting unit disposed between the light source and the objective lens includes a mirror set and a zoom lens set. The mirror set has at least a mirror. The mirror is rotatable such that after a light of the light source is projected to the mirror, the reflective direction of the light reflected from the mirror is changeable. The zoom lens set has at least a zoom lens disposed in accordance with the mirror. By rotating the mirror or changing the focal length of the zoom lens, the focusing location of the light changes on the focal plane of the objective lens or in the front or the rear of the focal plane.

Abstract: In one embodiment, an optical modulator has a Mach-Zehnder interferometer (MZI) and an optical resonator coupled, via a tunable optical coupler, to one of the MZI internal arms. The optical resonator induces in the MZI frequency-dependent optical losses characterized by a comb of spectral resonances. The coupling strength between the optical resonator and the MZI set by the optical coupler controls the magnitude of the loss due to the resonances, while one or more optical phase shifter located in the optical resonator controls the spectral position of the resonances. Either the optical coupler or the optical phase shifter, or both, can be tuned to adjust the modulator's radio-frequency response curve.

Abstract: Briefly, in accordance with one or more embodiments, a scanned beam display comprises one or more light sources to generate one or more light beams, a scanner module to receive the one or more light beams to generate a displayed image via scanning of the light beams onto a projection surface, and a spatial phase modulator disposed between the light source and the scanner module to phase modulate the one or more light beams to provide speckle reduction in the display image projected onto the projection surface.

Abstract: An afocal beam system corrects excess diffraction from phase error in microelectromechanical mirror offsets. One invention aspect interposes an opposing phase difference, between rays reflected at adjacent mirrors, varying the difference with mirror angle to make it roughly an integral number of waves. Mirror-array (not one-mirror) dimensions limit diffraction. Another aspect sharpens by generating and postprocessing signals to counteract phase difference. A third has, in the optical path, a nonlinear phase-shift device introducing a phase shift, optically convolves that shift with others from mirrors, then deconvolves to extract unshifted signals. A fourth varies mirror position in piston as a function of mirror angle to hold phase difference to an integral number of waves. A fifth aspect has, in the path, at least one delay element—whose delay varies as a function of mirror angle. A sixth has another mirror array in series with the first, matching their angles to introduce opposing phase difference.

Abstract: An apparatus and a method for changing optical tweezers are provided. The apparatus includes a diffractive optical element (DOE), a mask unit and an objective lens. The DOE includes a plurality of phase delay patterns. The mask unit includes a plurality of mask patterns that correspond to the phase delay patterns, respectively, wherein at least a portion of the mask patterns are complementary. A laser beam passing through each phase diffractive pattern correspondingly passes through each mask pattern to generate a compound diffractive pattern. The objective lens receives the compound diffractive pattern and focuses it on an examining object to form an optical tweezers.

Abstract: Duobinary and NRZ modulation of an X-Gb/s optical signal is achieved with a lumped element InP Mach-Zehnder device configured to operate at X/k-Gb/s where k>1 and arranged in a push-pull configuration.