Abstract: An optical free-space communication apparatus includes a first light-emitting source for emitting a first transmission optical beam having a plane of polarization in a predetermined direction, the first transmission optical beam being modulated according to a primary signal containing communication information, a second light-emitting source for emitting a second transmission optical beam having a plane of polarization perpendicular to the plane of polarization of the first transmission optical beam, the second transmission optical beam being modulated according to an auxiliary signal for angle detection, a transmitting optical system for emitting the first and second transmission optical beams out of the apparatus as optical beams each having a predetermined angle of divergence, and a driving unit for redirecting the outgoing paths of the first and second transmission optical beams, wherein the second transmission optical beam has a larger angle of divergence than the first transmission optical beam.

Abstract: A power source control apparatus has a constant current circuit and plural laser diodes. A first switching circuit is turned off, while a second switching element is turned on, before a laser beam is output from the laser diodes. Then, there is formed a circulating circuit for supplying electricity to a current controlling switching element and a reactor. At this time, a fixed constant current is supplied to the reactor, while kept at a command value. When a laser output command signal is generated, the first switching element is turned on, while the second switching element is turned off. Then, there is formed a circuit for supplying electricity to the current controlling switching element, reactor and laser diodes. At this time, influence of inductance of the reactor can be ignored. Thus, a constant current pulse with a steep rise and fall is supplied to the laser diodes.

Abstract: The larger the number of successive “0”s preceding a “1” in input data applied to a semiconductor laser, the longer the emission delay time of the laser. Accordingly, if a pulse signal for driving the semiconductor laser is made to rise earlier by an amount equivalent to the emission delay time conforming to the number of successive “0”s, thereby enlarging the pulse width, then the emission delay can be compensated for to eliminate pattern jitter irrespective of the number of successive “0”s. To accomplish this, a unit is provided for monitoring the number of successive “0”s in the input data, and a pulse-width adjustment circuit is provided for advancing the rise time of the laser driving pulse, thereby enlarging the pulse width, based upon the number of successive “0”s preceding a “1” in the input data.

Abstract: In a tunable laser device a plurality of basically identical lasers are arranged adjacent to each other in a line or row on a common substrate. The lasers can be DFB-type and they have different emission wavelengths, obtained from e.g. different pitches of gratings which define the wavelengths of the respective lasers. The lasers can be activated to emit light independently of each other by supplying electrical current to contacts located on the top sides of the lasers. When a laser is activated, the other lasers are biased, so that lasers located at one of side of the active laser will be transparent to the emitted light, which can then travel from the lasers through an electrooptic modulator, and the lasers located at the other side will absorb the light. By controlling the temperature the wavelength of emitted light can be finely adjusted.

Abstract: A laser activated semiconductor switching device has a semiconductor structure housed in a semiconductor structure housing, and a laser array assembly directly connected to the semiconductor structure housing. The laser array assembly houses a plurality of laser diodes and diode control circuitry which energizes the laser diodes to emit light directly onto a surface of the semiconductor structure, which can be the cathode or anode surface, to cause the semiconductor structure to generate current carriers which enable passage of current through the semiconductor structure. The device can further include a second laser array assembly which is connected to the side of the semiconductor structure housing opposite to that on which the first laser array assembly is connected, and is configured to operate in a manner similar to the first laser array assembly.

Abstract: An optical AND gate includes at least one semiconductor laser amplifier (SLA) and inputs for first and second optical signals. The gate produces an output corresponding to the AND product of A and B. In one aspect of the invention, the first and second signals are equal in wavelength. The gate may comprise a single SLA which receives the first signal A together with a third signal P, which may be a continuous wave pump. The second signal B is input in an orthogonal polarization state to A and P. Alternatively, the gate may comprise a pair of SLAs. A first SLA receives the first signal A together with the pump P. A sideband is selected from the output of the first SLA and input to the second SLA together with the second signal B. A sideband is selected from the output of the second SLA corresponding to the AND product C of A and P with B.

Abstract: An integrated electro-optical package including a dual sided opto-electronic device, composed of a substrate with an array of light emitting devices (LEDs) formed on a first major surface thereof, and at least one vertical cavity surface emitting laser formed on an opposed second major surface of the substrate. A mounting structure formed so as to allow for the mounting of the dual sided opto-electronic device on the interior major surfaces, and further having electrical conductors for cooperating with the LEDs and VCSEL of the opto-electronic device. A driver substrate having electrical connections for interfacing with the mounting structure and the dual sided opto-electronic device. A plurality of driver circuits connected to the mounting structure and dual sided opto-electronic device through connection pads formed on the driver substrate.

Abstract: The Vertical-cavity-surface-emitting Lasers with Optical Gain Control (V-LOGIC) form a family of integrated optical smart pixels for interconnect and signal processing applications. V-LOGIC devices consist of Vertical Cavity Surface Emitting Lasers (VCSELs) and In-Plane Lasers. (IPL) with cross-coupled cavities. The devices can operate in a digital, an analog or a hybrid mode. The IPLs either fully quench or modulate the VCSEL depending on whether the device is used in the digital or analog mode. In the Hybrid mode, one IPL serves as an enable input while another one modulates the VCSEL. The V-LOGIC devices can operate significantly faster than modulated lasers since, for the quenching phenomena, (1) the VCSEL carrier population is essentially constant and (2) the quenching is all-optical and does not require intermediate drive electronics. The family of devices solve the leading outstanding problems in optical switching and interconnect technologies.

Abstract: An electro-optical device includes a vertical cavity surface emitting laser, a heterojunction light emitting device and heterojunction phototransistor on a semiconductor substrate. Layers of the heterojuncticn phototransistor and the heterojunction light-emitting device are electrically and optically coupled so there is regenerative optical and electrical feedback between them. Layers of the heterojunction light-emitting devices are proton implanted to control the feedback. Plural such devices are electrically and optically coupled together to perform logic functions, such as EXCLUSIVE OR, in response to optical signals.

Abstract: An optical-scanning system including a laser, a multi-faceted, rotational scanning mirror, and system-monitoring laser safety structure operatively and informationally connected respectively to the laser and to the mirror and the drive motor for the mirror for altering the effective power output of the laser in response to current operational status of the system as determined by current operational status of the rotating mirror. The safety structure enforces on the laser a duty cycle of operation which is less than 100-percent, causes the laser to power down to a low "sleep" operating level at times other than during a normal scanning sweep, de-powers the laser entirely if either the drive motor for the mirror is not enabled or the rotational speed of the mirror is below full normal operating speed, and also positively de-powers the laser when a user shuts down the system.

Abstract: The present invention pertains to electronically controlled optical switching and interconnection arrangements enabling generation and processing of optical pulses including rerouting, serializing, modulation, and other processing or transformation of such pulses.

Abstract: An electro-optical device includes a vertical cavity surface emitting laser, a heterojunction light emitting device and heterojunction phototransistor on a semiconductor substrate. Layers of the heterojunction phototransistor and the heterojunction light-emitting device are electrically and optically coupled so there is regenerative optical and electrical feedback between them. Layers of the heterojunction light-emitting devices are proton implanted to control the feedback. Plural such devices are electrically and optically coupled together to perform logic functions, such as EXCLUSIVE OR, in response to optical signals.

Abstract: A QW diode laser generating orthogonally polarized multiple beams. The device incorporates quantum well active regions capable of, transitions to heavy hole and light hole band edges. The heavy hole transition provides TE-mode gain, while the light hole band provides mostly TM-mode gain. By controlling the compositions and thicknesses of the active regions, both modes can be obtained in a monolithic structure. In addition, the resulting laser polarization will be very sensitive to the threshold carrier density. With an intracavity loss modulator in such a structure, the polarization can also be controlled. Other ways of causing side-by-side lasers to operate, respectively, in their TE or TM modes are also described.

Abstract: An electro-optical device includes a vertical cavity surface emitting laser a heterojunction light emitting device and heterojunction phototransistor on a semiconductor substrate. Layers of the heterojunction phototransistor and the heterojunction light-emitting device are electrically and optically coupled so there is regenerative optical and electrical feedback between them. Layers of the heterojunction light-emitting devices are proton implanted to control the feedback. Plural such devices are electrically and optically coupled together to perform logic functions, such as EXCLUSIVE OR, in response to optical signals.

Abstract: The universally-applicable circuit arrangement of the invention makes possible an adjustment procedure for holding emitted optical power of a laser constant independent of temperature and aging. This circuit arrangement may be carried out as a three-stage cascade circuit supplied with operating voltages greater than 5 V. In accordance with the purpose of the invention, a circuit arrangement is provided which is universally applicable in a temperature range T=-40.degree. C. to 100.degree. C. for commercially available lasers and can be supplied by a standard 5 V source. In order to accomplish this as per the invention, differential amplifiers acting as current switches are arranged in a first cascade stage and the current sources feeding the differential amplifiers arranged in a second cascade stage. A data signal (D) serving to control the modulating current (I.sub.mod) is logically combined with a pilot signal (P) serving to control the pilot currents (I.sub.P1, I.sub.P2) in at least one cascade stage.

Abstract: Disclosed herein is an all-optical regenerator which is controlled by an external input optical signal for the generation of an output optical signal satisfying certain preset parameters defining the shape and the amplitude of the output optical signal. The optical device comprises a rectangular phase modulator optically coupled between two resonators so that the inlet mirrors of the resonators and the phase modulator form a nonlinear Fabry-Perot interferometer. The phase modulator serves to generate an output signal of a predetermined or desired pulse width and amplitude. The present optical device also includes a multielectrode injection laser which is optically coupled to the phase modulator. The multielectrode injection laser selects the clock frequency and locks output pulses in conformity with the period of the clock frequency.

Abstract: Logic function generator using an optical transposition in a distributed feedback laser diode. It comprises sources (LD1, LD2) of synchronous digital optical signals having the same rate, an optical coupler (10) receiving said signals and supplying an optical signal, a distributed feedback laser diode (LD3) into which is injected said optical signal, means (24) for the electrical polarization of said laser diode enabling the latter to supply a signal, whose optical frequency varies as a function of the optical power of the injected signal, an optical filter (12) which receives said signal and which is frequency tunable and control means (28) for the said filter. The latter supplies a signal which is a logic function of the signals of the sources. Application to optical calculation.

Abstract: A laser apparatus is provided in which a laser diode is driven with a plurality of drive pulses to generate a plurality of first laser pulses. Each first laser pulse occurs during a respective window and has a predetermined pulse width determined by a corresponding drive pulse. An electronic shutter which intercepts the laser beam is then opened in response to a trigger signal to permit a second laser pulse to be emitted from the laser rod during each window. The laser energy output of each of the second laser pulses from the laser rod is continuously monitored on a window by window basis to determine if the energy output of each of the second laser pulses exhibits a predetermined desired value. The energy output of the second laser pulse observed during each of the windows is then reported as a respective energy report signal set for each of the windows.

Abstract: A wavelength division multiplex type mode-lock laser device which simultaneously generates high-speed optical pulse trains for more than one wavelength. This device simultaneously generates high-speed optical pulse trains at two or more wavelengths. A ring resonator type mode-lock laser device or a Fabry-Perot type mode-lock laser device is modified so that it has an optical path difference providing structure which provides different refractive indices for the polarization directions which are at right angles at one another. This enables configuring a resonator corresponding to the optical path lengths formed according to the refractive indices and hetero-wave length optical path equalizing means to provide different refractive indices for different wavelengths.

Abstract: A photodiode (26) receives an optical input signal (P1) and an internal optical signal (P2) and supplies in response thereto an internal electrical signal (I2), which in turn controls a laser (4) which effects amplification and supplies the internal optical signal and an output signal (P3). The feedback loop formed by this photodiode and laser leads to a strong non-linearity in the variation of the output signal as a function of the input signal. The invention is useful especially in optical fiber telecommunications systems.

Abstract: Process for optical transmission by wavelength shifting and corresponding system. According to the invention, a wavelength hop corresponding to a mode hop of the laser is performed. The laser (20) is supplied by two currents, which fix the emission wavelengths (.lambda.1, .lambda.2).

Abstract: System and method for selectively inducing transparency to laser radiation in a material are described comprising a material having a ground state and two closely-spaced first and second excited states wherein the transition dipole moment d.sub.1 between the ground and first excited states is parallel to the dipole moment d.sub.2 between the ground and second excited states, and wherein d.sub.1 is substantially equal to zd.sub.2 where z is a scalar constant characteristic of the material, and wherein the frequencies of transition between the ground and first excited states and between the ground and second excited states are .omega..sub.o and .omega..sub.o +.DELTA., respectively, and a source of laser radiation for substantially totally irradiating the material with laser radiation of frequency .omega..sub.L substantially equal to .omega..sub.o +.DELTA./(1+z.sup.2).

Abstract: The system disclosed includes a light source (12) able to emit an intense, coherent, monochromatic beam, called the control beam, whose frequency is equal to the center optical frequency of one of several frequency multiplexed signals, which has been selected, an optical coupler (14) for coupling the signals and the control beam and an optical switching device (16) having an active material with a non-linear optical response, whose passband is narrower than the intervals separating the frequency band occupied by the selected siganl. The device receives the light from the optical coupler and supplies a beam reproducing the information of the selected signal. The invention can be used in telecommunications.

Abstract: A method of and apparatus for high speed modulation of a laser by controlling stimulated emission in the direction transverse main output. Because gain in either direction is derived from the same pool of excited carriers, lasing in the transverse direction depletes gain available in the longitudinal direction. The control of the forward output is achieved using either (1) transverse transmission regions depending on the applied bias or (2) transverse absorbing regions.

Abstract: A multi-channel/multi-layer optical gate contained within a fiber-optic housing having any number of optical cells disposed within the housing. The optical cells are made up of non-linear organic polymers surrounded by a piezoelectric crystal, which is in turn connected to a photovoltaic device. When the photovoltaic device is activated, the piezoelectric crystals cause the non-linear organic polymers to change their refractive index, causing an interruption of a reference laser beam. An output detector is disposed within the fiber-optic housing for detecting the reference laser beam.

Abstract: A laser amplifier package comprises two laser amplifiers coupled via two lenses and an optical isolator. The first and second laser amplifiers may both be run as amplifiers to give an overall improved gain and reduced residual facet reflectivity. The first amplifier may be run as a pulse source as part of an LEC or gain switched DFB laser assembly. Pulses generated to be, or compressed to, near transform limited enable the output from the package to be optical solitons. The second laser amplifier may be switched to provide modulation.

Abstract: Optical logic circuits utilize laser segments responsive to external optical signals to produce predetermined outputs in accordance with a desired logic function. Each segment has plural laser cavity legs joined at angled junctions to form at least part of a closed ring, with each segment including at least one light emitting, or exit, facet and at least one internally reflective facet at junctions of corresponding cavity legs. In a one-segment laser, the plural cavity legs form a closed ring. The laser is energized to propagate light in both directions around the ring, and external controls in the form of input light signals or reflective facets adjacent to a partially transmitting facet of the laser segment force unidirectional propagation to produce corresponding changes in the direction of emitted light from the laser. Multiple segments may be interconnected to produce more complex logic functions.

Abstract: A semiconductor laser element of which oscillation wavelength is variable at a wide range has a high operative efficiency.

Abstract: An optical mixer is provided for up/down-converting a first intensity-modulated optical signal (S1), the mixer comprising an optical amplifier (20) and gain-modulating means (23) for modulating the gain of the optical amplifier. The gain-modulating means (23) comprises means for generating a second intensity-modulated optical signal (S2) and launching it into the optical amplifier (20) at an intensity to cause the amplifier to operate at least partially within its saturated gain region. This causes the gain of the amplifier to be modulated at the frequency of modulation of the second optical signal (S2).

Abstract: An optical preamplifier includes a semiconductor optical amplifier monolithically integrated with an optical detector and electrically isolated from the detector by an isolation region. The isolation region consists of a low-loss, preferably transparent, insulating material whose index of refraction is matched to at least the refractive index of the amplifier, leading to reduced facet reflectivity at the amplifier output facet. Alternative device structures may include a waveguiding layer in the isolation region, a grating integrated with or following the optical amplifier, and a tuning region positioned between the amplifier and isolation region for filtering spontaneous emission.

Abstract: Disclosed is apparatus, exemplarily an electronic switching machine, that comprises novel and advantageous optical interconnection means. In particular, the apparatus comprises one or more digital electronic gates, and the output of the gate or gates is applied, without intervening amplifications, to a semiconductor laser whose radiation output is responsive to the applied electrical signal. The laser exemplarily is a quantum well laser of the type disclosed in U.S. patent application Ser. No. 407,608, U.S. Pat. No. 5,023,878, comprising at least one gain section and at least one loss section. The electrical output of the gate or gates is connected to the at least one loss section. Due to the ability of such lasers to be switched by means of a relatively very small current through the loss section, conventionally used drive amplifiers are not required in apparatus according to the invention, resulting in significantly reduced complexity and cost.

Abstract: A radiographic printer has a laser diode light source which is directly modulated by an input image signal. The laser diode has two operating regions, a linear laser region and a non-linear low-level light emitting region. The laser diode is amplitude modulated in the lasing region and is pulse width modulated in the light emitting region. A programmable digital delay produces the pulse width modulating signal and a digital comparator determines whether the laser diode operates in the amplitude modulation mode or the pulse width modulation mode. A current steering circuit is used in the pulse width modulation mode to rapidly switch the diode on and off. In addition, programmable digital to analog converters are used to compensate for changes in different diode slope efficiencies and threshold currents.

Abstract: An optical communication system is disclosed including an all-optical device whose output modulated optical beam is locked to an input modulated optical beam. In a specific embodiment of the system, the device may be a self-electro-optic effect device (SEED), which is operated as an oscillator by means of an associated tank circuit. Such an embodiment permits recovery of a clock frequency from a bit stream which is input into the device. When the output of the device is directed into an optical decision element, an all-optical regenerator may be realized.

Abstract: A controllable semiconductor laser system including a plurality of semiconductor regions operated at unequal saturation photon densities to permit optical and/or electrical control of lasing in at least one resonant cavity formed therebetween. A pair of such regions may operate as a controllable laser at greater than 100% differential quantum efficiency.

Abstract: Optical logic circuits utilize laser segments responsive to external optical signals to produce predetermined outputs in accordance with a desired logic function. Each segment has plural laser cavity legs joined at angled junctions to form at least part of a closed ring, with each segment including at least one light emitting, or exit, facet and at least one internally reflective facet at junctions of corresponding cavity legs. In a one-segment laser, the plural cavity legs form a closed ring. The laser is energized to propagate light in both directions around the ring, and external controls in the form of input light signals or reflective facets adjacent to a partially transmitting facet of the laser segment force unidirectional propagation to produce corresponding changes in the direction of emitted light from the laser. Multiple segments may be interconnected to produce more complex logic functions.

Abstract: The inventive quantum well opto-electronic devices of cavity length L.sub.C comprise, in addition to a "gain" section, a "loss" section that is optically coupled to the gain section but electrically substantially isolated therefrom. Through change of the electrical bias on the loss section the modal gain of the cavity can be changed. Devices according to the invention are useful in a variety of applications. Exemplarily, by making (in an inventive laser) L.sub.C /L.sub.A greater than about 20 (L.sub.A is the length of the loss section) and making the electrical isolation between the gain section and the loss section greater than about 3 k.OMEGA., fast amplitude modulation of the laser radiation is possibly. By applying appropriate AR coatings to the cavity of an inventive device, a fast variable-gain optical amplifier can be made. Finally, an inventive laser can be switched electrically between two widely spaced wavelengths, the wavelength difference being at least 10 nm.

Abstract: The I.sub.2 bound exciton in cadmium sulfide (bound to a neutral donor) is a very efficient radiator, providing low switching energy and fast switching times for an ON and OFF optical bistable device, desirable for all-optical signal processing applications. The optical bistable device for light at a given wavelength includes a Fabry-Perot cavity having a pair of opposed mirrored surfaces. A direct bandgap semiconductor, such as CuCl, CdSe, CdS, and GaAs having a bound exciton, is located within the cavity. The cavity is tuned near resonance of the light. The bound exciton has a coefficient of absorption tuned near resonance. A light beam of varying intensity is applied from without the cavity to one of the surfaces. The semiconductor has both an index of refraction and a coefficient of absorption that vary with the magnitude of applied light. Thus, light applied thereto passes through the device either substantially unimpeded or impeded, dependent upon its magnitude.

Abstract: The output polarization of a twin guide semiconductor laser is switched either by controlling the operating current of both guides or by injecting an optical signal. Twin-stripe and twin-ridge lasers of InGaAsP are described. True polarization bistability is reported for a range of devices: the effect is temperature insensitive.

Abstract: The characteristic parameters of a semiconductor laser (1) acting as an amplifier and brought to bistable operating conditions are determined. The output power (I2) of laser (1) is measured as a function of the power (I1) of an amplitude-modulated optical input signal to determine the laser hysteresis loop; the switching points (P1, P2) between the two stable states of the laser (1) are identified, the input and output power values relevant to such points are memorized, and at least the value of the non-linear refractive index coefficient (n.sub.2) of the material used to fabricate the laser (1) as determined starting from the power values relevant to at least one of said points (P1, P2). By exploiting the power values relevant to both switching points (P1, P2) also the amplification factor (A), the finesse parameter (F) of the passive cavity of the laser (1) and the wavelength difference (.lambda.1-.lambda.

Abstract: An optical transistor comprising two semiconductor lasers 1, arranged in a nonlinear ring vibrator 2, and two strip waveguides 3, each of which has a region A of optical coupling with the nonlinear ring vibrator 2, positioned on a common substrate. The regions of optical coupling are positioned diametrically opposite each other. The semiconductor lasers 1 have electrodes 4 for power supply. Each region A of optical coupling is provided with a control electrode 5 and each section of the nonlinear ring vibrator 2, located between the semiconductor 1 and corresponding regions of optical coupling, is also provided with a control electrode 6. Mirrors 7 form vibrators for the semiconductor lasers 1.

Abstract: By using a DFB semiconductor laser amplifier (1) in reflection, it is possible to obtain a device with an optical limiting characteristic. The output signal intensity of such an amplifier (1) is substantially independent of the input signal intensity where the input signal is detuned from an output peak on the short wavelength side of a stop band of the amplifier (1), and has an intensity above a threshold value. The amplifier (1) finds particular application for instance as an optical limiter or noise filter, in optical logic and communications systems.

Abstract: An optical logic circuit which is high in operation speed, low in power dissipation, and capable of operating at room temperature, possesses a semiconductor laser biased at a constant current higher than a threshold current. A light input is injected into the laser, the light input differing in the polarization direction of its oscillation mode. The output light of the semiconductor laser has a bistability characteristic with respect to the light input.

Abstract: An optical semiconductor device comprises cathode and anode regions, and a gate region having a forbidden band gap narrower than those of the cathode and anode regions. The gate region is sandwiched by the cathode and anode regions. The optical semiconductor device further comprises a plurality of windows for receiving and radiating lights so that the alignment of light axes can be easily performed for a plurality of input and output lights.

Abstract: Using a semi-conductor laser amplifier in reflection, an optical switch is achieved which can be applied as either an AND/OR, or a NAND/NOR, logic gate. The amplifier responds to an optical input switching signal and the logical characteristics of its response can be controlled by selection of the drive current to the amplifier. The switch finds application in optical logic or communication systems.

Abstract: An optically controlled laser device is used to perform digital logic functions. The device comprises a single mode semiconductor laser including a waveguide for coupling light into the lasing caving at an angle at or near normal incidence with respect to the laser radiation generated by the laser. The single mode properties of the laser are achieved by index guiding. The coupled light interacts with the laser radiation in a small region of the lasing cavity creating a perturbation that quenches the laser output, whereby input of the coupled light enables the laser device to perform logic functions.

Abstract: An opto-electric logic element comprises a semiconductor laser having a differential gain characteristic or an optical bistable characteristic and supplied with at least one light input, and a control circuit for varying an injection current supplied to the semiconductor laser in accordance with an input electrical signal. The logic element is capable of executing a logical operation between the optical signal and the electrical signal and can output the results of the logical operation as an optical signal.

Abstract: An optical control system and method comprised of obtaining optical bistability by radiating a crystal with both the exciton energy level and the excitonic molecule energy level as the optical excition energy level, with a laser beam having energy less than (Em/2-.gamma.), in which Em is the excitonic molecular energy level, an .gamma. is the half-amplitude level of absorption spectrum of two-photon resonance. The advantage of optical bistability is that high speed switching of an order of pico-seconds is possible due to the coherent non-linear response, and that switch-on and switch-off energy required is less than pico-Joule.

Abstract: A linear array of multimode laser diodes in a single wafer having a ratio of approximately one emitting stripe width to each non-emitting stripe isolation region width exhibits transverse lasing in a direction perpendicular to the normal laser output at input currents above a pre-determined transverse lasing threshold. Above the transverse lasing threshold, normal lasing is rapidly quenched.

Abstract: In an optical memory device comprising a bistable semiconductor laser having two coplanar electrodes (26, 27) injection current sources (31, 32) for the respective electrodes are individually adjusted to make the laser selectively latch first and second optical input signals (P1, P2). It is possible to provide an optical master-slave flip-flop device by optically directly coupling two optical memory devices of the type described to each other in tandem. Furthermore, an optical signal shifting device can be provided by arranging, optically in tandem, a plurality of optical master-slave flip-flop devices of the type described.

Abstract: A method of operating and apparatus for an optical bistable device is disclosed in which an active laser medium is placed between two mirrors within an optical resonator and bistable switching is achieved by operating the active resonator across the transition borderline between the stable and unstable resonator regions. Several different embodiments are disclosed.