Abstract: A visual display system is disclosed which utilizes one- and/or two-dimensional arrays of visible emitting vertical-cavity surface-emitting lasers (VCSELs) in order to provide a desired visual display within an observer's field of view. Sweep and subscanning techniques are employed, individually or in combination, to create a full M.times.N image from 1.times.L or K.times.L arrays of VCSELs, where M and N are multiple integers of K and L, respectively. Preferably, the VCSELs are contained within a display housing which may be attached to the head of the user by an attachment mechanism or may alternatively be hand held or mounted to a surface. The circular symmetry and low divergence of the emitted VCSEL radiation as well as the availability of multiple wavelengths, particularly, red, blue and green, allow high resolution monochrome or color images to be generated.

Abstract: The present invention is directed to an optical system which includes an image region having at least one light source which directs a beam of light along an optical axis and an object region which is adapted to receive the light from the light source. An optical delivery system is between the image region and object region. The optical delivery system receives the light from the image region and directs it to the object region. The optical delivery system is formed of a plurality of optical elements, such as lenses and volume holograms. The optical delivery system is designed to either receive a plurality of beams of light from a plurality of sources or different modes of a single light source and form a single spot of light in the image region having the combined power of all of the beams of light or modes of a single beam. The optical delivery system can also condense or expand the spacing between the beams of light from a plurality of light sources.

Abstract: A vertical-cavity, surface-emitting semiconductor laser having a substrate, an active layer of a semiconductor material which is adapted to generate light on a surface of the substrate, a pair of mirrors at opposite sides of the active layer and means for expanding the diameter of the output beam. Such means include a spacer layer of an optically passive material between the active layer and at least one of the mirrors, and mirror layers of reduced difference in index of refraction, interface layers having intermediate indices of refraction placed between mirror layers, in either case expanding the effective optical cavity length to at least 100 times the thickness of the active material in the active layer. Another means is anti-waveguiding which directly expands the diameter of the beam. The expanded cavity provides an output beam of larger diameter while maintaining stable single mode emission. The spacer layer may be a separate layer or region over the substrate or at least a portion of the substrate.

Abstract: Optoelectronic integrated circuits are disclosed comprising a vertical-cavity surface emitting laser (VCSEL) and a transistor. The VCSEL comprises a laser cavity sandwiched between two distributed Bragg reflectors. The laser cavity comprises a pair of spacer layers surrounding one or more active, optically emitting quantum-well layers having a bandgap in the visible range which serve as the active optically emitting material of the device. The thickness of the laser cavity is m .lambda./2n.sub.eff where m is an integer, .lambda. is the free-space wavelength of the laser radiation and n.sub.eff is the effective index of refraction of the cavity. Electrical pumping of the laser is achieved by heavily doping the bottom mirror and substrate to one conductivity-type and heavily doping the regions of the upper mirror with the opposite conductivity type to form a diode structure and applying a suitable voltage to the diode structure.

Abstract: A three-dimensional optical interconnection is disclosed having a stack of vertically aligned optoelectronic integrated (OEIC) modules. Each OEIC module includes an array of vertical cavity surface emitting lasers (VCSEL), receivers and electronic logic which are monolithically integrated on a single semiconductor substrate. Communication between the OEIC modules is effectuated by the free space propagation of laser radiation from the VCSELs to corresponding receivers on an adjacent OEIC module. Transistors, such as heterojunction bipolar transistors, may be used to drive the VCSELS.

Abstract: A vertical-cavity surface-emitting laser is disclosed comprising a laser cavity sandwiched between two distributed Bragg reflectors. The laser cavity comprises a pair of spacer layers surrounding one or more active, optically emitting quantum-well layers having a bandgap in the visible which serve as the active optically emitting material of the device. The thickness of the laser cavity is m .lambda./2n.sub.eff where m is an integer, .lambda. is the free-space wavelength of the laser radiation and n.sub.eff is the effective index of refraction of the cavity. Electrical pumping of the laser is achieved by heavily doping the bottom mirror and substrate to one conductivity-type and heavily doping regions of the upper mirror with the opposite conductivity type to form a diode structure and applying a suitable voltage to the diode structure. Specific embodiments of the invention for generating red, green, and blue radiation are described.

Abstract: Vertical-cavity surface-emitting lasers (VCSELs) are disclosed having various intra-cavity structures to achieve low series resistance, high power efficiencies, and TEM.sub.00 mode radiation. In one embodiment of the invention, a VCSEL comprises a laser cavity disposed between an upper and a lower mirror. The laser cavity comprises upper and lower spacer layers sandwiching an active region. A stratified electrode for conducting electrical current to the active region is disposed between the upper mirror and the upper spacer. The stratified electrode comprises a plurality of alternating high and low doped layers for achieving low series resistance without increasing the optical absorption. The VCSEL further comprises a current aperture as a disk shaped region formed in the stratified electrode for suppressing higher mode radiation. The current aperture is formed by reducing or eliminating the conductivity of the annular surrounding regions.

Abstract: Reduction of laser threshold in an electrically pumped vertical cavity laser is the consequence of interpositioning of an electrode layer intermediate the active, photon producing region, and at least one of the two Distributed Bragg Reflectors defining the laser cavity. The advance is a consequence of the lowered pump circuit resistance due to elimination of one or both DBRs--in particular, to elimination of the p-doped DBR--from the pump circuit.

Abstract: A reduced-blocking system where a perfect shuffle equivalent network having a plurality of node stages successively interconnected by link stages, is advantageously combined with expansion before the node stages and/or concentration after the node stages in a manner allowing the design of a system with arbitrarily low or zero blocking probability. An illustrative photonic system implementation uses free-space optical apparatus to effect a low loss, crossover interconnection of two-dimensional arrays of switching nodes comprising, for example, symmetric self electro-optic effect devices (S-SEEDs). Several low loss beam conbination techniques are used to direct multiple arrays of beams to an S-SEED array, and to redirect a reflected output beam array to a subsequent node stage.

Abstract: Optical apparatus for performing wavelength-dependent beam combination. The apparatus relies on a polarization beam splitter in combination with other optical elements to develop combined beams with the same polarization type and that are therefore suitable for polarization-dependent combination with other beam arrays. A dichroic mirror, which is used as the wavelength-dependent element of the apparatus, is oriented such that the incident beams are substantially perpendicular to the mirror. With this orientation, the dichroic mirror achieves near-ideal performance even with beam arrays having a substantial angular field. The apparatus also uses two plates which, although designed for operation as quarter-wave plates at one of the two wavelights being combined, are oriented with their respective fast axes substantially perpendicular to each other such that polarization conversions, effected by the plates on beams having the other of the two wavelengths, substantially cancel each other.

Abstract: A method of making a vertical-cavity surface emitting laser and method of making in which a III-V heterostructure is epitaxially grown to include a quantum well active region between two interference mirrors separated by an emitting wavelength of the quantum well region. A small pillar of this heterostructure is etched by chemically assisted xenon ion beam etching. Prior to etching, a top metal contact is deposited on the epitaxial semiconductor. Light is emitted through the substrate having a bandgap larger than that of the quantum well region.

Abstract: Distributed feedback mirror cavities are found capable of sufficient reflectance-loss characteristics to permit lasing in two or a single quantum well structure in which lasing is in the thin (quantum) dimension. Such lasers sometimes known as "quantum well surface emitting lasers" are of sufficiently low threshold value as to permit use in integrated circuits of high integration density--e.g. at 1 micron design rules. Anticipated uses, now made possible, include optical circuitry for computer chip interconnect as well as optoelectric integrated circuits for many purposes including computing itself.

Abstract: A vertical-cavity surface emitting laser and method of making in which a III-V heterostructure is epitaxially grown to include a quantum well active region between two interference mirrors separated by an emitting wavelength of the quantum well region. A small pillar of this heterostructure is etched by chemically assisted xenon ion beam itching. Prior to etching, a top metal contact is deposited on the epitaxial semiconductor. Light is emitted through the substrate having a bandgap larger than that of the quantum well region.

Abstract: Apparatus according to the invention comprises an optical, or opto-electronic device that comprises one or more "trapping" layers that can speed the decay of a non-equilibrium carrier distribution in an active region of the device, thereby improving device characterstics. In preferred embodiments the trapping layers are arranged so as to increase the likelihood of radiative recombination of carriers leading to erased heat sinking requirements.

Abstract: A radiant energy logic element includes first and second reflecting devices and a radiant energy nonlinear medium between said first and second reflecting devices and in contact therewith. Radiant energy beams of first and second wavelengths are applied to the reflecting devices. The first reflecting device is transmissive at said second radiant energy beam wavelength and reflective at said first radiant energy beam wavelength, and said second reflecting device is reflective at said first and second radiant energy beam wavelengths. The nonlinear medium of the logic element is responsive to radiant energy beams applied to the first reflecting device but insensitive to radiant energy beams applied to the second reflecting device.

Abstract: The inventive method for forming monolithic nonlinear Fabry-Perot etalons comprises depositing on an appropriate substrate, e.g., a GaAs wafer, a first multilayer mirror, depositing on the first mirror a spacer typically comprising optically nonlinear material, and depositing a second multilayer mirror onto the spacer. Typically, at least one of the mirrors is an active mirror comprising optically nonlinear material. Deposition can be by a known process, e.g., by MBE or MOCVD. Since, inter alia, the method comprises no critical etching steps it can be used to produce high finesse etalons that have uniform properties over relatively large areas. The inventive method can be adapted to the manufacture of transmissive etalons. It can also be used to produce arrays of optically isolated etalons. Devices comprising nonlinear etalons manufactured by the inventive method can be incorporated, for instance, into optical data processing apparatus, or into optical communications apparatus.

Abstract: Optical pulses of nominal frequency f.sub.o and of predetermined repetition rate .tau..sub.M.sup.-1 can be generated by means of the induced modulational instability in single mode optical fiber, provided the fiber has anomalous dispersion at f.sub.o. A particularly advantageous method for generating such pulses that is capable of very high repetition rates is disclosed. The method involves coupling first and second cw or quasi cw optical radiation, of frequencies f.sub.1 and f.sub.2, respectively, into the optical fiber. Frequently one of the two radiations has much greater amplitude than the other. The resultant radiation in the fiber has frequency f.sub.o between f.sub.1 and f.sub.2, and is sinusoidally modulated with frequency .vertline.f.sub.1 -f.sub.2 .vertline.. Propagation of the resultant radiation through the fiber results in steepening and narrowing of the amplitude peaks. The length of the fiber typically is chosen such that, at the output, the pulse width .tau..sub.p <.tau..sub.

Abstract: An optical logic element in which energy absorption is approximately constant is described.

Abstract: An optical logic apparatus includes a plurality of logic elements on a single passive, nonlinear Fabry-Perot etalon characterized by a shift in transmissivity in response to increased incident light, a source producing a probe beam having a first wavelength which does not significantly modify the index or refraction of the nonlinear medium, and a plurality of sources of input beams each representing a respective logic signal. The input beams all have a wavelength which significantly modifier the index of refraction of the nonlinear medium. The probe beams illuminate the surface of the etalon. The input beams are mapped by a lens onto the etalon, which produces a plurality of output beams each representing various logical functions of the input beams, which logical functions are determined by the frequency of the various probe beams. The output beams become input beams which are optically mapped, in combination with additional probe beams, onto a second etalon.

Abstract: An optical flip-flop system having a pair of optically aligned nonlinear Fabry-Perot etalons, one of which acting as a bistable optical device, the other acting as a negative optical gate. The negative optical gate is initially tuned for high transmission and will remain transmissive until impinged upon by a first optical pulse, at which time it will momentarily become nontransmissive. If this nontransmissive state is longer than the recovery time of the bistable optical device, then the bistable optical device will become nontransmissive. The bistable optical device will remain nontransmissive until impinged upon by a second optical pulse. Thereupon, the bistable optical device will remain transmissive until such time the negative optical gate becomes nontransmissive again. In this manner the flip-flop system can be readily controlled by the application of the pair of optical pulses thereto.