Abstract: A method and apparatus for transmitting a modulated optical signal includes a continuous source of light, a first optical modulator for generating an optical pulse stream in response to a radio frequency (RF) driving signal and a DC bias signal, and a second modulator for modulating the optical pulse stream with an electrical data signal. A processor dithers the phase of the RF driving signal using a first dither signal and the level of the DC bias signal using a second dither signal. The processor detects the first and/or second dither signals in the modulated optical signal and adjusts the phase of the RF driving signal and/or level of the DC bias signal to null the detected first and/or second dither signal.

Abstract: The optical domain optical signal sampling device is for sampling an optical signal-under-test and comprises a semiconductor saturable absorber, an optical sampling pulse source, an optical signal input and a light detector. The optical sampling pulse source is arranged to illuminate the semiconductor saturable absorber with optical sampling pulses. The optical signal input is arranged to illuminate the semiconductor saturable absorber with the optical signal-under-test. The light detector is arranged to receive optical samples of the optical signal-under-test output by the semiconductor saturable absorber in response to the optical sampling pulses.

Abstract: A light-modulating system, includes: a light source for emitting a sequence of light pulses at a period Tp; a light modulator having a variable-width switching profile with rise and fall times Tr and Tf respectively, wherein the greater of Tr and Tf is greater than Tp, the light modulator modulating the sequence of light pulses; and a controller for controlling the width of the variable-width light switching profile.

Abstract: A conventional electrochromic mirror comprises an ion conductive layer provided between a transparent electrically conductive substrate and a reflective electrically conductive substrate and containing spacers. The spacers can be perceived when the mirror was viewed. According to the present invention, the difference in refraction index between the spacers and the ion conductive layer is ±0.03 or less. Therefore, the electrochromic mirror having spacers in the ion conductive layer which are hardly perceived can be provided.

Abstract: One embodiment of the invention relates to producing optical pulses for use on a transmission link. A light source is configured to produce an optical signal. A pulse generator is coupled to the light source. The pulse generator is configured to receive, for a first channel, the optical signal and a clock signal. The pulse generator is also configured to modify the optical signal based on the clock signal to produce an optical pulse having a predetermined pulse shape. The clock signal is associated with the predetermined pulse shape.

Abstract: The present invention provides a signal integrity measurement method and apparatus which allows for signal characteristics to be measured by obtaining samples taken at the midpoint of the data stream. The invention provides a measurement device that is suitable for use in the field to provide a measurement of signal characteristics within transmitted data streams. The invention is particularly suitable for field measurement of signal characteristics of data streams or continuous in-line monitoring of signal characteristics within transmitted data streams. The signal characteristics include, but are not limited to eye opening jitter, noise, slope efficiency, average power and peak-to-peak amplitude.

Abstract: An integrated high speed driver/modulator assembly includes a driver amplifier assembly having a specified input impedance, such as 50 ohms. The driver/modulator assembly also includes an optical modulator having a modulator transmission line. The impedance of the modulator transmission line is less than the specified input impedance, which results in a reduced V&pgr; for the optical modulator. The reduction in V&pgr; enables the driver/modulator assembly to more effectively support OC-768 and higher data rates of at least 40 Gb/s.

Abstract: A light-modulating system, includes: a light source for emitting a sequence of light pulses at a period Tp; a light modulator having a variable-width switching profile with rise and fall times Tr and Tf respectively, wherein the greater of Tr and Tf is greater than Tp, the light modulator modulating the sequence of light pulses; and a controller for controlling the width of the variable-width light switching profile.

Abstract: In an optical amplifier evaluation instrument, a rectangular spectrum light source 1 transmits continuous light having a wide-band and flat spectrum shape, a first optical modulator 2 receives and pulse-modulates the continuous light. Further, a second optical modulator 3 operates in the same period as the first optical modulator 2 and performs the on/off pulse operation, thereby providing a sampling window in a time domain for extracting and suppressing an optical signal. A modulation signal generation section 4 performs such control and drive. An optical signal undergoing pulse intensity modulation is input to a measured optical amplifier 6. Post-amplified signal light power for each frequency component and amplified spontaneous emission power for each frequency component in a time domain in which no optical pulse signal exists are measured and operations are performed for each wavelength.

Abstract: Devices and techniques for processing an analog signal by using optical pulses at a high sampling rate. Parallel analog-to-digital conversion channels can be implemented to achieve high-speed analog-to-digital conversion.

Abstract: An adaptive pulse compressor is described, especially for use with ultrashort pulses, wherein the input pulses are modified in an iterative fashion, according to a feedback signal obtained from measurement of the output pulses. The feedback signal is programmed, by means of a programmable spatial light modulator, to allow for independent control of the individual spectral components of the incoming pulses, such that almost arbitrary phase functions can be realized to accomplish efficient compression. One of the main disadvantages associated with prior art pulse compressors, namely, the need for characterization of the uncompressed pulses, is thus eliminated. The compressor is thus capable of handling completely uncharacterized or partially characterized input pulses, or pulses from time varying sources.

Abstract: A pulse interleaver splits an input pulse train into at least two optical branches (20,22). A first one of the branches (20) carries a first signal, and is terminated with a mirror (24) and a device (26) for manipulating the state of polarization. The reflected signal is re-combined at a combiner (18) with a second signal on a second one of the branches (22). The effective path lengths for the first and second signals between the input and the combiner are selected such that the input pulse train is interleaved with itself thereby providing an output with increased frequency. The mirror (24) and the device for manipulating the state of polarization (26) provide a predetermined relationship between the polarization of pulses in the output pulse train derived from an individual pulse of the input pulse train.

Abstract: An optical pulse observing device enables the clear observation of indirect laser light of pulse laser light. The optical pulse observing device to be used by a user for observing pulse illumination light directly or indirectly, includes an optical shutter means that operates for alternate opening and closing in synchronism with periodic pulses of the pulse laser light so as to open only during the duration of pulses of the pulse laser light to pass pulse laser light and external light.

Abstract: A method and apparatus for modulating light, wherein a light source provides light of a certain wavelength to be modulated by a layer of superconducting material which forms part of a specifically configured plate assembly. The superconducting layer is placed in the optical path of the light source. Further the superconducting layer is switched between a partially transparent non-superconducting state and a substantially non-transparent superconducting state by a modulation circuit. The resulting optical pulses transmitted through the superconducting layer are converted from the original wavelength to a lower wavelength by a frequency converting device.

Abstract: A sampling device that samples a first signal by modulating a second signal using the first signal, comprising: a holding circuit that holds a value of the first signal; a modulator that modulates the second signal using a difference between the value held by the holding circuit and a present value of the first signal to produce a third signal indicating the difference; and an adder that adds the difference indicated by the third signal to the value held by the holding circuit. Preferably, the first signal is an electric signal, the second signal is an optical signal, and the modulator modulates the optical signal by applying to the optical signal an electric field formed by the electric signal.

Abstract: Devices and techniques for processing an analog signal by using optical pulses at a high sampling rate. Parallel analog-to-digital conversion channels can be implemented to achieve high-speed analog-to-digital conversion.

Abstract: An apparatus includes a driving voltage generator that generates a pulse driving voltage having a rising edge and a decaying edge. An optical modulator produces a first pulse at the rising edge of the pulse driving voltage and a second pulse at the decaying edge of the pulse driving voltage. Therefore, the first and second pulses are both produced from a single driving pulse voltage. The frequency of the first pulse is determined by the slope of the rising edge of the pulse driving voltage and the frequency of the second pulse is determined by the slope of the decaying edge of the pulse driving voltage. The first and second pulses are transmitted through a transmission line. A detection device detects the first and second pulses after being transmitted through the transmission line.

Abstract: A rearview mirror assembly is disclosed including a housing adapted to be mounted to the vehicle, a mirror disposed in the housing, at least one electrically powered device disposed in the housing, and a power supply for receiving power from a vehicle power source having a voltage in excess of about 24 V and for supplying power at a voltage of about 5 V or less to the electrically powered device. The electrically powered device and the power supply exhibit an electromagnetic interference level of less than about 41 dB&mgr;V/m for emissions in the frequency range from about 0.4 MHz to about 20 MHz. The mirror is preferably an electrochromic mirror, and the electrically powered device may be a control circuit for the electrochromic mirror.

Abstract: A device and technique to sample an analog signal by optical pulses at a high sampling rate. Parallel analog-to-digital conversion channels can be implemented to achieve high-speed analog-to-digital conversion.

Abstract: An optical intensity modulator with optimized extinction ratio (ER) is provided. The optical intensity modulator has a modulator used to receive a light source, such as a laser source, and export an optical pulse. An optical divide is used to receive the optical pulse and decouple it into a first optical pulse and a second optical pulse. An optical receiver is used to receive the first optical pulse and convert it into an electrical pulse signal. A signal processor is used to receive the electrical pulse signal from the optical receiver and digitize it into a digital reference signal. A DC-bias generator coupled to the signal processor and the modulator is used to provide a precise DC bias to the modulator according to an output of the signal processor. A current reference signals is compared with a previous reference signals and is adjusted in the signal processor so as to obtain the precise DC bias.

Abstract: Optically generated charge carriers in an optically responsive medium, such as an optical switch, which are produced in response to a first pulse of optical radiation (P1), are de-excited by directing a second pulse (P2) of optical radiation into the medium. The second pulse occurs while the excitation produced by the first pulse remains coherent, and the relative phase of the first and second pulses is selected so that the second pulse destructively interferes with the excitation produced by the first pulse. The apparatus may be used as an optical switch or as a photodetector.

Abstract: A light modulation system, wherein a light source provides light of a certain wavelength to be modulated by a material layer, which forms part of a specifically configured plate assembly. The modulation layer is placed in the optical path of the light source. Further, the modulation layer is switched between first and second states, and cooperates with the light source to produce a train of pulses at a given pulse rate. The resulting optical pulses transmitted through the modulation layer are converted from the original certain wavelength to a lower wavelength by a frequency converting device.

Abstract: For the generation of amplified, phase-coherent light pulses, a sequence of phase-coherent, equidistant input light pulses (21) is coupled into a resonator device (1) with at least two resonator mirrors (11, 14), forming a light path (10) with a predetermined resonator length, in such a way that the coupled in input light pulses in the resonator device are linearly superimposed in succession to form at least one circulating light pulse, whereby the circulating light pulse is coupled out of the resonator device as an output light pulse (31) as soon as the circulating light pulse has reached a preset minimum level of energy.

Abstract: An illumination device utilizing a pulse modulation technique of a solid state light source to provide increased light output for a given heat load. In a preferred embodiment, power is supplied in pulses to periodically activate a short wavelength (i.e., blue) emitting LED, which in turn stimulates a phosphor-based color conversion system to produce sustained white light. In response to a pulse of power, the LED emits an intense burst of short wavelength light. The burst of light from the LED briefly excites the phosphor system, producing a bright illumination. During the interval while power is dissipated in the LED, the LED warms. After the pulse ends and before the next pulse begins, the LED cools because no more power is dissipated in the LED. However, the phosphorescent behavior of the phosphor system causes it to continue to glow for a period of time after being excited. The intensity of the illumination produced by the phosphor gradually decays during this period.

Abstract: An image displaying apparatus and method is provided which can provide a satisfactory display with a gradation of intensity even with a spatial light modulator which provides a binary light modulation. A light from a light source 1 is modulated by a spatial light modulator 3 which modulates a light at each pixel thereof correspondingly to a pixel data of an image to be displayed. When the pixel state of the spatial light modulator 3 is being changed, the light source 1 is turned off. When the pixel state of the spatial light modulator 3 is steady, a light pulse is irradiated from the light source 1 to the spatial light modulator 3 to display the image.

Abstract: A photonic band gap structure device and method for delaying photonic signals of a predetermined frequency and a predetermined bandwidth by a predetermined delay is provided. A Fabry-Perot delay line device has several regions of periodically alternating refractive material layers which exhibit a series of photonic band gaps and a periodicity defect region, interposed between the regions of periodically alternating refractive material layers. The Fabry-Perot delay line device imparts a predetermined delay to photonic signals that pass therethrough. The introduction of the periodicity defect region into this photonic band gap structure creates a sharp transmission resonance within the corresponding photonic band gap of the structure and causes at least an order of magnitude improvement in photonic signal delay for a band-edge delay line device of similar size. Variable photonic delays to multiple photonic signals are also generated by this Fabry-Perot delay line device.

Abstract: Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

Abstract: An access system based on piezo-electric transducer assembly or electro-optic device light beam deflector assembly which on application of electric signals deflects light beams, which are then passed through total internally reflecting surfaces to increase the separation between beams, is described. The light beams fall on large area information storage surface, such as optical disk or magnetic disk, for the purpose of reading and writing. The access time to the information is very fast. The nature of the reflected light from the memory surface is detected to read the digital signals stored on the surface as is conventionally done in the art. Except for the small friction-free movements of the piezo-electric transducers there are no moving parts for access to the storage surface. Instead of the memory surface a screen may be placed when tthe light beams can be used after large separation to form a fast display.

Abstract: A liquid crystal display panel gray shade driving device comprises first circuitry for applying row signals represented by a set of orthonormal functions to a group of row electrodes throughout one frame by set sequential scanning for each of selecting periods, and second circuitry for sequentially carrying out a dot product computation between the set of orthonormal functions and a set of pixel data consisting of bits, and applying a column signal having a voltage level corresponding to a result of the computation to each of a group of column electrodes in synchronization with the set sequential scanning for each of the selecting periods. The first circuitry has a vertical driver for applying the row signal, by doubling the rate thereof, to the group of row electrodes and repeating the same set sequential scanning at least for two frames of previous and subsequent frames.

Abstract: When producing an object by subsequent solidification of material layers 1 at places corresponding to the object there is a problem of limited production speed because the scanning speed or laser power of the light beam scanning the material layer 1 cannot be increased at will, if the light beam 4 used for solidification is focused as required for exact resolution. According to the invention this problem is solved by providing a variable focusing device 8 in the light beam 4, whereby the focus of the light beam 4 can be varied during the solidification of the layer 1. Thus, a different focus, laser power and scanning speed can be used in different regions of the layer 1.

Abstract: A display device includes a vertical driver for applying to row electrodes a set of row signals represented by a set of orthogonal functions supplied by an orthogonal function generator at each selection period by group-sequential scanning within one frame. A dot product processor successively carries out a dot product computation between the set of orthogonal functions and a set of pixel data. A horizontal driver applies to column electrodes column signals having voltage levels determined by the results of the dot product computation at each selection period in synchronization with the group-sequential scanning. A frame memory stores the pixel data for each frame in divided bit form. The dot product processor reads out the set of stored pixel data in divided bit form and executes the dot product computation to produce a column signal component for each respective bit.

Abstract: An optical transmission system comprises an optical transmitter for transmitting an optical signal, comprising an optical modulator for modulating a intensity of the optical signal in accordance with a binary digital NRZ (nonreturn-to-zero) electric signal and outputting a transmission optical signal, and means for supplying the electric signal and thereby driving the optical modulator, the means including means for adjusting a waveform of the electric signal supplied to the optical modulator so that a timing with which the optical signal outputted from the optical modulator transits from a high level to a low level is later than a timing with which the optical signal transits from the low level to the high level, an optical fiber with wavelength dispersion for propagating the signal light transmitted from the optical transmitter, and an optical receiver for receiving the optical signal propagated along the optical fiber and reconstituting an electric signal from the optical signal.

Abstract: A display system having a greyscale control arrangement for controlling light output from a plurality of optical fibers includes a light source effective for supplying a high brightness light output to the input ends of the plurality of optical fibers. A plurality of piezoelectric shutter members are disposed adjacent the light delivery ends of the optical fibers and are effective for controlling the delivery of light output through the optical fibers as a function of the on or off condition thereof. The delivery ends of the optical fibers are disposed relative to one another so as to form a plurality of display pixels. At least two of the optical fibers are combined to form each of the pixels. The diameters of the at least two optical fibers that make up each pixel are different thereby allowing that at least four different greyscale levels can be achieved for each display pixel.

Abstract: The frequency components of an input pulse are dispersed into divergent respective rays that are applied to an acousto-optic modulator after being collimated. The amplitude of each frequency component emerging from the modulator is determined by the amplitude and phase of a grating formed therein by modulated radio frequency wave applied to it. The parallel rays emerging from the modulator are focussed onto a device for forming an output pulse.

Abstract: There is provided a peak compression circuit including detection device for detecting that value of an input signal has exceeded a predetermined set value, a pulse generation device for generating, based on the result of the detection, a pulse signal constituted of frequency components which have no substantial adverse influence on the input signal and having a polarity in a direction of reducing the parts of the input signal exceeding the predetermined set value, a delay device for delaying the input signal so that there is a phase match between the generated pulse signal and the portions of the input signal exceeding the predetermined set value and an addition device for adding the delayed input signal and the pulse signal. There is further provided a light transmitter including the peak compression circuit and a light source for outputting a light signal which has been intensity-modulated by the output signal of the peak compression circuit.

Abstract: An optical pulse generator for producing a soliton pulse train having a modulator which amplitude and phase modulates an optical frequency output of a continuous optical wave source. The modulator is driven by first and second harmonically related continuous sinusoidal waves from first and second CW voltage sources and the generator includes a pulse compression means for producing at the output of the generator a soliton pulse train.

Abstract: A temporal imaging system is presented consisting of a dispersive input path, a phase modulator producing a phase modulation substantially equal to A+Bt.sup.2, and an output dispersive path. This temporal imaging system can be combined with other temporal lenses to image input signals in the same manner that spatial lenses can be used to image light from spatial sources. In particular, this temporal imaging system can be used to expand, compress and or invert input temporal signals.

Abstract: The source includes an electro-absorption modulator receiving a continuous light wave supplied by a laser emitter 10. The characteristic response curve of the modulator has a threshold so that the modulator transmits an optical pulse having a duration which is less than the duration of an electrical control pulse which is applied to the modulator by a control generator. Soliton-type optical pulses obtained in this way are transmitted via a line fiber to a receiver. Application to optical transmission.

Abstract: An image processing apparatus having a third-order nonlinear stimulated photon echo medium (1). The photon echo medium (1) can store large numbers of images in the form of a Fourier transformed pattern by spectral modulation. The spectral modulation is carried out by sending optical pulses in an optical pulse train having (or not having) image information to the medium (1) so that the population in the ground and excited states are modulated after the passage of the pulse trains and pulses. The Fourier transformed pattern is converted back to temporal modulation, consisting of a sequence of echo pulses that reproduce the original data pulse train. By using the apparatus, ultrafast operation such as convolution and correlation between a number of reference images and a test image can be achieved.

Abstract: A harmonics generation element which comprises a nonlinear optical element having single-crystals of lithium niobate containing magnesium of less than 5 atomic per cent. The nonlinear optical element has 3 ppm or less of impurity Fe and is configured so that a primary laser beam is made incident into the nonlinear optical element and a secondary output light having a wavelength of higher-order harmonics is emitted therefrom.

Abstract: Optical communication systems, optical computing systems and optical logic elements which rely on the phenomena of cross-phase modulation to alter and control, either or simultaneously, the spectral, temporal or/and spatial properties of ultrashort light pulses for processing information with high speed repetition rates. A weak beam of ultrashort light pulses is modulated by an intense beam of ultrashort light pulses by copropagating both beams through a non-linear medium such that cross-phase modulation effects are realized.