Abstract: Techniques for reducing frequency shifts in an oscillating frequency of an opto-electronic oscillator by having at least two separate optical delay elements in an optical portion of an opto-electronic feedback loop.

Abstract: The present invention relates to a modulated light source, in particular for use as part of an opto-electronic communication network. The modulated light source has a laser and an external electro-optic modulator for modulating the intensity of light produced by the laser. A temperature sensor senses the temperature of the laser and the modulator. A control circuit connected to the temperature sensor adjusts the bias on the modulator so that the band edge of the modulator follows the changes in wavelength of the laser as the laser warms up during operation. This avoids the need for a cooling element to keep the temperature of the laser constant.

Abstract: A multi-gas sensor is provided which modulates a polarized light beam over a broadband of wavelengths between two alternating orthogonal polarization components. The two orthogonal polarization components of the polarization modulated beam are directed along two distinct optical paths. At least one optical path contains one or more spectral discrimination elements, with each spectral discrimination element having spectral absorption features of one or more gases of interest being measured. The two optical paths then intersect, and one orthogonal component of the intersected components is transmitted and the other orthogonal component is reflected. The combined polarization modulated beam is partitioned into one or more smaller spectral regions of interest where one or more gases of interest has an absorption band.

Abstract: A return-to-zero (RZ) modulator for an optical transmitter comprises a Mach-Zehnder interferometer optically coupled with a light source for modulating a continuous wave generated the said light source with a drive signal. A drive circuit generates a drive signal for modulating the Mach-Zehnder device to generate an optical RZ pulse signal with adjustable width. The drive circuit comprises a trigger flip-flop for converting a non-return to zero (NRZ) signal to a modified drive signal. A method of generating an optical RZ pulse signal comprises converting a non-return to zero (NRZ) signal to a modified drive signal, and modulating a continuous wave from a light source with the modified drive signal to generate an optical RZ pulse signal. The width of the pulses in the optical RZ pulse signal is controlled by adjusting the rise and fall time of the modified drive signal.

Abstract: The present invention discloses an electronically frequency tunable and phase modulatable quasi-optic grid oscillator. The oscillator includes a reference signal input port whereby a small external reference signal is introduced that entrains the frequency and phase of the oscillator signal to it. Amplitude modulation techniques are introduced to further enhance the utility of the oscillator as a modulator.

Abstract: An optical device for modulating optical signals in a wavelength division multiplexed communication system. The device includes a plurality of phase modulators. Each of the phase modulators is configured to provide an associated phase modulated optical signal. Each of a plurality of optical filters receives an associated one of the optical signals and is configured to amplitude modulate the optical signal as an optical filter output signal. The optical filter output signals may be combined onto an aggregate path to a receiver including receiver optical filters for selecting the transmitted channels.

Abstract: An optical communication system (10), a method (100) for parallel modulation of an optical spectrum and a method (200) for parallel demodulation of the optical spectrum of modulated optical frequencies by the system (10) are described. The optical frequencies are provided in parallel to a modulation section (14) for modulating with data bits from a data signal source (16). The data bits are associated with an optical modulator (58) that controls passage of the optical spectrum at a plurality of predetermined optical frequencies based upon the data bits. The optical frequencies of the optical spectrum, modulated by the data bits, are then transmitted via a communication section (18) to an optical receiver (20) that is coupled to a demodulation section (22) of the system (10). Modulated optical frequencies are received as a modulated optical spectrum and demodulated in parallel by an optical demodulator (92) to derive the data bits.

Abstract: The present invention provides a method and a system for generating a phase-modulated wave front. According to the present invention, the spatial phase-modulation is not performed on the different parts of the wave front individually as in known POSLMs. Rather, the spatial phase-modulation of the present invention is performed by generating an amplitude modulation in the wave front, Fourier or Fresnel transforming the amplitude modulated wave front, filtering Fourier or Fresnel components of the Fourier or Fresnel distribution with a spatial filter such as a phase contrast filter, and regenerating the wave front whereby the initial amplitude modulation has transformed into a phase-modulation.

Abstract: Methods and apparatus directed to using modulation to substantially improve detection limits in optical imaging, and to substantially improve the performance of various optical imaging systems. In an illustrative embodiment, such modulation is achieved using a modulated light source, a modulation frequency reference, a detector, and a demodulator. The modulated light source may comprise a light source emitting an inherently modulated output: alternately, this modulated light source may comprise a separate optical modulator and a continuous wave, modulated, or pulsed light source configured so as to impose a modulation in the output of light source. Methods for imaging using such modulation are also disclosed.

Abstract: A micro-opto-electro-mechanical systems (MOEMS) modulator based on the phenomenon of frustrated total internal reflection (FTIR). The modulator effects amplitude and phase modulation at the boundary of a waveguide. Wavelength-specific switching is achieved by spatially separating the wavelength channels by dispersing a broadband input signal into its wavelength components through a grating. In exemplary embodiments, an array of micro-fabricated actuators is used to switch or modulate wavelengths individually. Applications include wavelength and space-resolved phase and amplitude modulation of optical beams, and re-configurable add/drop switching of dense wavelength-division multiplexed (DWDM) optical communication signals.

Abstract: An optical device includes a grounded base and an optical modulator chip having a top surface, a back surface and side surfaces. The optical modulator chip is positioned on the grounded base with the back surface facing the grounded base. The optical modulator chip includes a first ground electrode, a signal electrode and a second ground electrode located over the top surface of the optical modulator chip. The first and second ground electrodes of the optical modulator chip are interconnected on a surface of the optical modulator chip.

Abstract: An optical amplitude modulator for modulating signals for transmission by a fibre optic link. The modulator comprises of a plurality of optical transmitters, whereby each transmitter is driven by an electronic circuit. Generally, each optical transmitter provides a light output, and the light outputs of the plurality of optical transmitters are combined optically for transmission as an optical output signal. Additionally, each of the plurality of optical transmitters has an associated optical filter, whereby each filter has a different level of opaqueness. Each filter, filters light output from the associated optical transmitter.

Abstract: The present invention relates to an electrical field absorbing semiconductor optical modulator, more particularly, to a high speed semiconductor optical modulator and a fabricating method thereof. The present invention includes a high speed semiconductor optical modulator, the optical modulator formed by stacking an n-type light-wave guiding layer, a light absorbing layer, a p-type light-wave guiding layer, a p-type clad layer, and a p-type ohmic contact layer on a substrate successively, the optical modulator having a ridge structure wherein the optical modulator is an electric-field absorbing type, and wherein width W3 of the light absorbing layer is less than the width W1 of the p-type ohmic contact layer. Accordingly, the present invention enables to provide high speed optical modulation of tens of giga rate of which modulating characteristics are excellent by reducing contact resistance and capacitance, which are the major problems of ruining the characteristics of an optical modulator, simultaneously.

Abstract: An optical modulation scheme for transmitting data over a fiber optic transmission line is proposed where the following steps are realized:

Abstract: An optical amplitude modulator for modulating signals for transmission by a fiber optic link. The modulator comprises of a plurality of optical transmitters, whereby each transmitter is driven by an electronic circuit. Generally, each optical transmitter provides a light output, and the light outputs of the plurality of optical transmitters are combined optically for transmission as an optical output signal. Additionally, each of the plurality of optical transmitters has an associated optical filter, whereby each filter has a different level of opaqueness. Each filter, filters light output from the associated optical transmitter.

Abstract: An optical modulator having a voltage-optical output characteristic in which optical output varies periodically with respect to a voltage value of an electrical drive signal is driven by a modulator driving voltage signal, which has an amplitude of 2·V&pgr; between two light-emission culminations or two light extinction culminations of the voltage-optical output characteristic. A low-frequency superimposing unit superimposes a prescribed low-frequency signal on the modulator driving voltage signal, and an operating-point controller controls the operating point of the optical modulator by detecting operating-point drift of the optical modulator based upon the low-frequency signal component contained in an optical signal output from the optical modulator and controlling the bias voltage of the optical modulator in dependence upon the drift of the operating point of the optical modulator.

Abstract: A hologram that can obtain high diffraction efficiency when reconstructed and is superior in productivity is provided. An arbitrary object image and a recording surface in which representative points are disposed with predetermined pitches are defined by use of a computer. At the position of each individual representative point, a complex amplitude for the wave front of object light emitted from the object image is calculated, and a complex amplitude distribution is calculated on the recording surface. This complex amplitude distribution is expressed by a three-dimensional cell having a groove in the surface thereof. Four kinds of groove depths are defined in accordance with the phase &thgr;, and seven kinds of groove widths are defined in accordance with the amplitude A.

Abstract: The present invention discloses an electronically frequency tunable and phase modulatable quasi-optic grid oscillator. The oscillator includes a reference signal input port whereby a small external reference signal is introduced that entrains the frequency and phase of the oscillator signal to it. Amplitude modulation techniques are introduced to further enhance the utility of the oscillator as a modulator.

Abstract: An optical image shutter is provided having a multiplicity of thin layers of alternating narrow and wide gap semiconductor material stacked to form an MQW structure and electrodes located on at least two semiconductor surfaces of the image shutter, wherein the electrodes are configured so that a voltage difference applied between them produces an electric field that is temporally and spatially substantially uniform in the volume of the MQW structure and wherein the aperture of the image shutter is greater than 4 square mm.

Abstract: Methods and apparatus for isolating a modulation region of an external modulator that has a semiconductor waveguide structure that comprises at least one integral isolation region.

Abstract: The novel electrochromic system comprises at least one reducible and at least one oxidizable substance OX2 and RED1 respectively, which are linked with one another via a bridge member, and is outstandingly suitable for use in an electrochromic device.

Abstract: A solid state device used to modulate the intensity of reflected or transmitted light by modulating with an external voltage the optical thickness of a thin film ferroelectric placed in an etalon cavity is disclosed. The device is constructed by selecting a generally planar supporting substrate, preferably silicon or sapphire in order to be compatible with silicon integrated circuits. A dielectric stack consisting of alternating layers of different index of refraction materials, also specifically selected to be compatible with later growth of the thin film ferroelectric, is deposited thereon to form a partially reflective and partially transmitting mirror, followed by a transparent electrically conductive layer. The thin film ferroelectric is deposited on the conductive layer, followed by a second transparent conductive layer and a second dielectric stack. Leads are connected to the conductive layers and in turn to a voltage generator.

Abstract: In an optical communication system, efficient use of a Mach-Zehnder modulator requires accurate knowledge of the AC halfwave voltage at the desired modulation frequency. At high modulation frequencies this can be difficult to measure directly. A method of accurately measuring the AC halfwave voltage of a Mach-Zehnder modulator is described. The Mach-Zehnder modulator is biased at the peak of the transfer function curve and a sinusoidal signal of known amplitude and the desired frequency of measurement is applied. The optical power is measured with and without the sinusoidal signal. The ratio of the two optical powers is used in the Mach-Zehnder transfer equation to calculate the AC halfwave voltage.

Abstract: A wideband semiconductor electro-absorption optical modulator including a semiconductor core shorter in absorption-peak wavelength than a wavelength of optical signal, and an electrode for applying an electric signal to absorb the optical signal by shifting the absorption-peak wavelength to a long wavelength region when a voltage is applied, wherein an electric signal input port and an electric signal output port are disposed so that the electrode is constructed in the form of a traveling-wave electrode, and a total thickness of non-doped layers including the semiconductor core is reduced to decrease a driving voltage. Degradation of optical modulation bandwidth and reflection characteristics of the electric signal caused by mismatching of characteristic impedance to an outer circuit are reduced by decreasing an interaction length of the electric signal and the optical signal.

Abstract: An optical arrangement comprising a plurality of cells arranged in a two-dimensional array on, into, or partly into an optical medium, each said cell having a pattern structure comprising a number of grooves which are parallel to each other and which form a grating. The grating of each cells forms at least two sections which are displaced in relation to each other by a predetermined distance in a direction which is essentially perpendicular to the longitudinal direction of the grooves. The grooves of two or more adjacent cells are unaligned with one another for controlling the phase or amplitude of one or more incident optical waves when the cells receive the incident optical waves.

Abstract: A method and apparatus for modulating a light beam in an optical processing system is described. Preferably, an electrically-controlled polarizer unit and/or an analyzer unit are utilized in combination with a spatial light modulator and a controller. Preferably, the spatial light modulator comprises a pixelated birefringent medium such as a liquid crystal video display. The combination of the electrically controlled polarizer unit and analyzer unit make it simple and fast to reconfigure the modulation described by the Jones matrix of the spatial light modulator. A particular optical processing objective is provided to the controller. The controller performs calculations and supplies control signals to the polarizer unit, the analyzer unit, and the spatial light modulator in order to obtain the optical processing objective.

Abstract: The bias point of an electro-optic modulator, such as an Mach-Zender modulator, is automatically controlled. A pilot signal, preferably two pilot tones at different frequencies, is applied to the modulator. The output of the modulator then contains various components resulting from the pilot signal. An error signal is generated, preferably coherently, based on one of these components, termed the pilot component, which preferably is located at the difference frequency of the two pilot tones. A bias signal which controls the bias point of the modulator is adjusted based on the error signal. The coherent generation of the error signal facilitates feedback loops based on phase and/or amplitude control and also supports locking the electro-optic modulator to a bias point with a preselected slope (either negatively or positively sloping).

Abstract: When an intensity modulating operation and a phase modulating operation are carried out by employing a 2-electrode MachZehnder type optical modulator preferably a LN-MZ type optical modulator, a drive signal of this 2-electrode LN-MZ type optical modulator is produced from an intensity modulation signal and a phase modulation signal with a low loss and a simple arrangement.

Abstract: An ultra high resolution wave focusing method and apparatus is disclosed. The invention provides a focusing system having an effective numerical aperture greater than that possible using known conventional focusing techniques. By the method and apparatus of the invention, a wave of arbitrary wavefront profile and wavelength .lambda. is focused to a region of high amplitude having a spot size that approaches the fundamental limit of 0.25.lambda.. Imaging and patterning systems employing such a wave focusing method and apparatus provide ultra high resolution and ultra small feature sizes beyond the capabilities of systems utilizing conventional focusing elements.

Abstract: A wideband semiconductor electro-absorption optical modulator including a semiconductor core shorter in absorption-peak wavelength than a wavelength of optical signal, and an electrode for applying an electric signal to absorb the optical signal by shifting the absorption-peak wavelength to a long wavelength region when a voltage is applied, wherein an electric signal input port and an electric signal output port are disposed so that the electrode is constructed in the form of a traveling-wave electrode, and a total thickness of non-doped layers including the semiconductor core is reduced to decrease a driving voltage. Degradation of optical modulation bandwidth and reflection characteristics of the electric signal caused by mismatching of characteristic impedance to an outer circuit are reduced by decreasing an interaction length of the electric signal and the optical signal.

Abstract: A projection display apparatus includes a light source, a spatial light modulation device, a condenser lens, an aperture stop, and a projecting lens. When the spatial period of complex amplitude modulation in the spatial light modulation device is represented by p, the center wavelength of the incident light is represented by .lambda., and a half angle subtended by an area around an opening edge of the aperture stop at the condenser lens along the first direction is represented by .theta.asx, parameters of the light source, the spatial light modulation device, the condenser lens, the screen, the aperture stop and the projecting lens and a relative positional relationship therebetween are defined such that the following condition is satisfied:0.35<.theta.asx/arcsin(.lambda./p)<0.6.

Abstract: A light modulator for both intensity and phase modulating coherent light on a pixel-by-pixel basis includes a modulating material responsive to an electric potential for modulating the intensity of coherent light passing through the modulating material, and electrodes for applying an electric potential across the modulating material on a pixel-by-pixel basis. The coherent light associated with a first set of pixels has a different optical path length through the modulating material than does the coherent light associated with a second set of pixels. The modulating material is a liquid crystal material. The electrodes include a set of first reflective pixel electrodes embedded in the liquid crystal material, the first reflective pixel electrodes having a first thickness, and a set of second reflective pixel electrodes embedded in the liquid crystal material, the second reflective pixel electrodes having a second thickness.

Abstract: The instant invention relates to a method and a device for optical phase modulation by means of semiconductor amplifiers. In this case an optical semiconductor amplifier comprises optical waveguides 10, which rise over its length and change in its lateral extension, so that light supplied at the optical inlet 11 undergoes an amplification on its way to the optical outlet 12.

Abstract: An integrated digital light modulator. In one embodiment, a light beam is split into a set of binary weighted beams which are then individually switched on or off by an optical switch. The weighted beams which are conveyed by the optical switches are then recombined to produce a modulated beam. In this manner, a fast inexpensive integrated digital light modulator may be advantageously obtained. Broadly speaking, the present invention contemplates a digital optical power modulator that comprises a binary power divider and an optical modulator. The binary power divider is configured to receive an input light beam and split it into a set of weighted beams. The optical powers of the weighted beams are related in that the ratio of the optical powers of any two weighted beams is substantially an integer power of two. The optical modulator receives the set of weighted beams from the binary power divider and receives a digital signal.

Abstract: A linearized external modulator transmitter with improved dynamic range includes a limiter and a subtractor, which each receive one or more time-varying input signals. The limiter generates a first signal with an amplitude that is confined to a range bounded by preset positive and negative levels, wherein, between the preset levels, the transmitter has an optical power output that is linearly related to the input signal. The first signal is passed through a predistortion circuit connected to an external modulator as well as into the subtractor, which generates a signal equal to the amount by which the input signal exceeds, either positively or negatively, the limited first signal. The subtractor sends the excess signal to a tunable gain circuit connected to a laser. The laser is connected to the external modulator, which generates the optical power output of the transmitter. The transmitter can be adapted to include dual sets of inputs--e.g.

Abstract: An electro-absorption optical modulator, where a waveguide length of the absorption layer is denoted by L, a light confinement coefficient thereof is denoted by .GAMMA., and a performance factor of the absorption layer at an applied voltage V to an absorption layer is denoted by K(V), has design parameters selected so that a relationship .vertline.K(V)-.GAMMA..multidot.L.vertline. .ltoreq.0.005 cm is satisfied in a continuous operation range of a quenching ration T.sub.Att. The waveguide length L is preferably optimizrd so as to satisfy K(V).apprxeq..GAMMA..multidot.L in the operation range.

Abstract: An electro-optic modulator and a method for its use, in which an optical carrier is effectively suppressed for transmission of a radio-frequency (rf) modulating signal over an optical communication link, to provide improved demodulator performance. A carrier component is recovered from the modulator, amplified, and reused, to minimize the effect of optical carrier losses. In one embodiment of the invention, a modulator (10) with complementary output ports (20 and 22) generates a carrier-suppressed output (FIG. 2B) containing rf sidebands from one port (20) and a strong carrier component (FIG. 2C) from the other output port (22). The carrier component is filtered in a residual sideband filter (14), amplified in an optical amplifying medium (12) and returned to the modulator (10) as its carrier input. In a second embodiment of the invention, a modulator (30) with a single output port produces rf sidebands and a suppressed carrier component (FIG.

Abstract: The invention provides a circuit for amplitude modulating an optical signal with an N-state electrical signal where N is greater than or equal to 2, the circuit comprising a modulator having a first input for receiving the optical signal to be modulated and a second input for receiving a modulating electrical signal. According to the invention, the circuit comprises, upstream from the second input, shaping component having an input receiving the N-state electrical signal and having an output that switches from one of the N states to another of the N states in response to the N-state electrical signal taking up a level that is greater than a predetermined threshold, and switching from the other state to the one of the N states in response to the N-state electrical signal taking up a level that is less than the predetermined threshold, the predetermined threshold being associated with the pair of states, and having a level that lies between and is different from the respective levels taken by the two states.

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 main signal is amplitude-modulated by a predetermined low frequency signal generated by a low frequency signal generator, and a bias voltage generated by a bias voltage applying circuit of an initial bias setting circuit is superimposed thereon by an adder to generate a modulation signal. An external modulating device is driven by the modulation signal to generate an optical signal. The optical signal generated by the external modulating device is branched by an light branching device, and converted to an electrical signal by a light-electricity converting device, and a component corresponding to the low frequency signal is extracted by a filter. A multiplier detects the extracted low frequency signal by use of the low frequency signal generated by the low frequency signal generator. A voltage level of the bias voltage is changed based on a difference between a level of an obtained detection signal and a predetermined reference voltage.

Abstract: An intracavity-modulated laser includes a gain element, an electro-optic modulator (EOM), a frequency selective coupler (FSOC), and an optical isolator coupled in such a way that a ring laser cavity is formed. The EOM selectively affects the optical input in intensity, phase, or frequency according the radio frequency (RF) input signal applied. The FSOC is a three-port device that receives light at a first port and passes narrowbands of light out a second port and directs the remaining optical spectrum out a third port. The optical isolator assures single direction lasing. When the gain is sufficient to overcome the ring losses, the laser cavity will oscillate with longitudinal modes corresponding to the pass bands of the FSOC. The light exiting the second port of the FSOC is amplified by the laser gain element and is directed to the EOM. The EOM modulates each carrier (longitudinal mode) of the laser cavity thereby creating optical modulation sidebands associated with each carrier.

Abstract: The fiber optic true time delay modulator generates a continuously variable true time-delay (i.e., phase shift) by utilizing the dispersion characteristic of a single mode optical fiber. The signal to be variably delayed modulates a continuous wave optical signal from a tunable laser source which is applied to a dispersive optical fiber wherein the phase shift occurs. The optical intensity output of the dispersive optical fiber is converted back into electrical energy by a photodetector for use in radio frequency, microwave and millimeter wave electronic devices. The invention can be used to generate multiple synchronized output signals by using a multiple wavelength laser or by combining outputs from several independently tuned lasers. Also. frequency and phase shifting is inherently provided by modulating the time delay.

Abstract: A phase-contrast DMD based image system 36 for projecting an amplitude and phase modulated image. A flexure beam DMD array 34 is used to allow analog phase modulation of reflected light 38. The phase modulation is converted to amplitude modulation by the phase-contrast imaging optics including a phase plate 42. The resulting amplitude modulated wave is flicker-free and does not need to be synchronized to optical image sensors.

Abstract: A variable sensitivity compensation network for a Mach-Zender optical modulator comprising first and second pilot signal sources f.sub.1 and f.sub.2, a signal coupler for combining the pilot signals with an RF information signal for modulating a bias-controlled Mach-Zender optical modulator, a variable sensitivity feedback loop comprising an optical detector for detecting the pilot signals from the modulator output, a bandpass filter for selecting the sum frequency f.sub.1 and f.sub.2, a voltage variable attenuator for adjusting the sensitivity of the loop, a logarithmic compression circuit for compressing the f.sub.1 and f.sub.2 signal level from the variable attenuator, means for measuring the signal level, means for controlling the variable attenuator and means for producing an analog bias signal for controlling the operating point of the Mach-Zender modulator. The measuring and controlling means include a microprocessor.

Abstract: An amplitude optical modulator which utilizes a two-electrode DFB laser structure. The amplitude optical modulator includes a current generator which can modulate at least one of two currents injected into the DFB laser structure. This modulation displaces a spontaneous emission peak of the DFB laser structure, which leads to an amplitude modulation of the injected optical beam. Such an amplitude optical modulator may find particular application in an optical telecommunications system.

Abstract: A light shutter array to be employed in an optical head for a color display, a color printer or the like. The light shutter array has at least three lines of shutter elements which are made of a material having an electrooptic effect. In tile lines, shutter elements which have conductor-filmed windows and shutter elements which have bare windows are staggered. The shutter elements with bare windows function as light shutters, and the shutter elements with conductor-filmed windows function as electrodes. The shutter elements with bare windows in each line are driven in accordance with red, green or blue image data.

Abstract: Apparatus, and a corresponding method for it use, for directly modulating an optical carrier with a radio-frequency (rf) electrical signal. A semiconductor electroabsorptive modulator is operated at an optical wavelength and electrical bias voltage carefully selected to provide a near-linear electrical-to-optical transfer characteristic and to keep rf insertion loss low. Further reduction of insertion loss is achieved by use of an extremely short device, or a single quantum well device configuration, or both. Linearity is further optimized by choosing an appropriate combination of optical polarization mode, optical reflectivity of the device facets, and the number and physical properties of multiple quantum wells.

Abstract: An optical filter device comprised of two parallel arrays of lenses. Each lens in the first array faces a lens in the second array to form a pixel. Lens pairs in a pixel are separated by the sum of their focal distances and include in their common focal surface a "smart" layer for modulating light passing through the focal surface. Preferred embodiments include car rear view mirrors, sunglasses, glasses for night driving, laser goggles, nuclear goggles, sun visors, sun shields, windshields, space suit helmet visors, optical instrument protection devices, window filters and energy conservation devices.

Abstract: An optical shutter device for use, e.g., in an optical printer includes a plurality of electrooptic chips each having a plurality of very small segments for optical modulation. The optical shutter device has a voltage adjusting circuit which individually supplies the driving voltage to the chips depending on the light transmitting characteristics intrinsic to the chips. Thus, even when the chips have different light transmitting characteristics, the image produced by the chips will have a uniform intensity.

Abstract: An electric field absorption light modulation unit includes a light emission device for emitting light and a modulation device for varying a light transmittance thereof of light applied by the light emission device so as to provide the light as a result of modifying thereof. A driving signal generating unit coupled with the electric field absorption light modulation unit generates a driving signal to be applied to the modulation device from an input information signal by making the modulation device vary the light transmittance thereof, and the driving signal generating unit provides the driving signal so that the driving signal in a fluctuation range in which an undesirable level fluctuation may be present, corresponds to a constant working range of the modulation device, the light transmittance thereof staying at a constant value in the constant working range.