Abstract: A monolithic multi-wavelength laser diode array having a composite active region of at least two dissimilar quantum well layers that are partially mixed in at least one of their constituent atomic species in at least one area of the active region. Different areas of the active region are characterized by different emission wavelengths determined by the degree of intermixing. An impurity free interdiffusion, such as vacancy enhanced interdiffusion, is used to provide the intermixing. Each area may have one or more waveguides and distributed Bragg reflector gratings tuned to the emission wavelength of the corresponding area of the active region. Each area or waveguide may also be separately pumped with an individually addressable current injection electrode. The laser output may be coupled into a ferroelectric frequency doubler integrally formed on the array substrate.

Abstract: A high density surface emitting semiconductor LED or laser array is coupled with a driver circuit substrate for modulating the light emitted from the array. This modulated light is imaged by optical means onto a photosensitive recording medium of an opto-electronic line printer. The imaging optical means can be either a single or multiple lens system.

Abstract: Multiwavelength laser sources that are precisely aligned relative to each other and suitable, for instance, for multistation, multicolor ROS. The device is made by growing on a semiconductor substrate a set of epitaxial layers in a laterally injecting laser configuration with progressively narrower bandgap quantum well active regions (and therefore progressively longer wavelength operation) towards the surface of the crystal. Selective etching can then be used to remove all quantum wells with emissions shorter than the ultimately desired wavelength in a given cavity. This approach can be applied to three different types of laser structures; conventional edge emitting lasers, grating surface emitting lasers, and vertical surface emitting lasers. Also described is a vertical cavity, surface-emitting laser with lateral injection employing a reflector structure comprised of a III-V semiconductor layer beneath the active region, and a reflecting mirror above the active region.

Abstract: A buried-layer semiconductor structure solving the problem of defect and dislocation generation which typically results when impurity induced layer disordering occurs across interfaces where there are changes in both the column III and the column V constituents in the manufacture of III-V compound semiconductors, for use, for example, in lasers. The structure is characterized by a thin buried active layers entirely bounded by thick layers on a substrate. Defect generation is avoided by maintaining the thin layer below a critical thickness and lattice matching the thick layers to the substrate.As a further feature, the problem of relatively poor thermal conductivity in AlGaInP based laser structures is avoided by minimizing the amount of AlGaInP material contained in the laser structure, restricting these materials only to the critical active layers, and using AlGaAs for the majority of the optical guiding and carrier confining layers.

Abstract: The present invention is an apparatus and method for providing detection of a laser output on a semiconductor wafer. A laser cavity and a detection cavity are formed on a semiconductor wafer in parallel such that light emitted laterally from the laser cavity is detected by the detection cavity. The amount of light detected can then be transformed into data, which in turn can be used to control the output of the laser.

Abstract: A laser recorder for recording images on a substrate in response to a video signal having a frequency which defines a pixel time (during which a single pixel is imaged) includes a duty cycle modulating digital to analog (D/A) converter which outputs a variable duty cycle high frequency signal, based upon an intensity controlling N-bit input, to a power controller which then controls the intensity of a light beam output by a laser based upon the variable duty cycle high frequency signal. The duty cycle modulating D/A converter outputs a high frequency variable duty cycle bitstream including a repeating cycle of fixed amplitude pulses, a total duration of all of the pulses in each cycle varying based upon the N-bit input signal.

Abstract: Scanning laser crystallization of p- and n- type hydrogenated amorphous silicon alloy cladding layers enhances the doping efficiency of such layers without changing the luminescence or other important properties of the middle i-layer in a p-i-n device. The dc dark conductivity of the doped layers increases by a factor of about 100 to about 10,000 above a sharp laser energy density threshold whose magnitude increases with decreasing impurity concentration. In one method, a doped amorphous silicon alloy layer is deposited on an amorphous glass substrate, scanned with laser irradiation, and then an intermediate i-layer is formed over this layer. Another doped amorphous silicon alloy layer is deposited on this layer, doped oppositely from the first doped layer. The second doped layer is then crystallized by scanning laser irradiation, leaving the underlying i-layer virtually unchanged in optical and electronic properties.

Abstract: A lateral heterojunction bipolar transistor (LHBT) comprises emitter and/or collector regions forming a p-n heterojunctions at the emitter/base junction and at the collector/base junction with a planar base region wherein at least the emitter region is formed by employing impurity induced disordering (IID) to produce emitter or collector region of wider bandgap than the base region. The lateral heterojunction bipolar transistor of this invention can also double as a hetero transverse junction (HTJ) laser.

Abstract: Scanning laser crystallization of p- and n-type hydrogenated amorphous silicon alloy cladding layers enhances the doping efficiency of such layers without changing the luminescence or other important properties of the middle i-layer in a p-i-n device. The dc dark conductivity of the doped layers increases by a factor of about 100 to about 10,000 above a sharp laser energy density threshold whose magnitude increases with decreasing impurity concentration. In one method, a doped amorphous silicon alloy layer is deposited on an amorphous glass substrate, scanned with laser irradiation, and then an intermediate i-layer is formed over this layer. Another doped amorphous silicon alloy layer is deposited on this layer, doped oppositely from the first doped layer. The second doped layer is then crystallized by scanning laser irradiation, leaving the underlying i-layer virtually unchanged in optical and electronic properties.

Abstract: A technique for producing pixel patterns at different selected wavelengths. A diode laser is repeatedly pulsed and has its temperature changed from pulse to pulse, which causes the output wavelength to change. This allows pixel patterns to be interlaced by the use of dispersive elements such as prisms in the optical train. A temperature shift of about 15.degree. C. provides a wavelength shift of about 30 angstroms, which is usable. A temperature shift of 20.degree. C.-30.degree. C. or more is preferable. The temperature shifts may be accomplished by supplying specific currents below threshold and above threshold. For two-wavelength operation, the laser is driven at a first bias current below threshold for a first non-illumination interval, at a first pulse current above threshold for a first illumination interval, at a second bias current below threshold for a second non-illumination interval, and a second pulse current above threshold for a second illumination interval.

Abstract: The present invention is an apparatus and method for providing detection of a laser output on a semiconductor wafer. A laser cavity and a detection cavity are formed on a semiconductor wafer in parallel such that light emitted laterally from the laser cavity is detected by the detection cavity. The amount of light detected can then be transformed into data, which in turn can be used to control the output of the laser.

Abstract: A high density surface emitting semiconductor LED array comprises disordered regions extending through a contact layer, a second confinement layer, an active layer and partially extending through a first confinement layer to define optical cavities therebetween the disordered regions, individual contacts on the contact layer aligned with each disordered region inject current through the optical cavity to a contact on a substrate causing emission of light from the active layer in the optical cavity through the surface of the contact layer. The first confinement layer can be replaced with a DBR to form an enhanced LED array. Both confinement layers can be replaced with DBRs to form a laser array. The first confinement layer can be replaced with a distributed Bragg reflector (DBR) and a dielectric mirror stack can be formed on the contact layer to form a laser array.

Abstract: This disclosure pertains to compound semiconductor, such as AlGaAs, surface skimming hetero-transverse junction (HTJ) lasers and improved heterojunction bipolar transistors (L-HBTs). These lasers and transistors are structurally consistent with each other, so they can be fabricated in the same set of epitaxial layers for integrated optoelectronic applications. The surface skimming characteristic of the HTJ lasers provided by this invention enables them to be configured relatively easily, without requiring any epitaxial regrowth, to operate as DFB lasers in axial or surface emitting configurations and to function as harmonic generators. Single and multiple base channel L-HBT transistors, as well as structurally corresponding single and multiple quantum well surface skimming HJT lasers are disclosed.

Abstract: A lateral heterojunction bipolar transistor (LHBT) comprises emitter and/or collector regions forming a p-n heterojunctions at the emitter/base junction and at the collector/base junction with a planar base region wherein at least the emitter region is formed by employing impurity induced disordering (IID) to produce emitter or collector region of wider bandgap than the base region. The lateral heterojunction bipolar transistor of this invention can also double as a hetero transverse junction (HTJ) laser.

Abstract: Monolithic high density arrays of independently addressable offset semiconductor laser emitters or elements are able to be placed in close center-to-center proximity, e.g., on 3-10 .mu.m centers, without experiencing any undesirable phase locking and with minimal amount of electrical and thermal interaction or crosstalk occurring between the independently addressed lasing elements and their independent operation in ROS printer applications. With a proper offset in the laser emitters, interlace scanning relative to an image bearing surface, which is required with other multiple emitter lasers in ROS printer applications, is eliminated thereby permitting adjacent line scanning of an image bearing surface without complicated optics and electronics.

Abstract: A window laser having at least one window region with a transparent waveguide layer optically coupled to an active region generating lightwaves. The waveguide layer is characterized by a broader guided transverse mode for the lightwaves than the active region and may have a thickness which is greater than the active region, a refractive index difference with respect to cladding layers which is less than a refractive index difference between the active region and the cladding layers, or both. The waveguide layer may be coupled to the active region via a transition region characterized by a gradual change in the guide mode width of the lightwaves, such as from a tapered increase in thickness of the waveguide layer in a direction away from the active region.

Abstract: Monolithic high density arrays of independently addressable semiconductor laser emitters or elements are able to be placed in close center-to-center proximity, e.g., on 3-10 .mu.m centers, without experiencing any undesirable phase locking and with minimal amount of electrical and thermal interaction or crosstalk occurring between the independently addressed lasing elements and their independent operation. Such design features are highly suitable for high speed raster output scanner (ROS) and laser printing applications.

Abstract: An optically uncoupled laser array is modified at its current confinement geometry to introduce nonuniformity in effective optical cavity width and/or length among the different lasers comprising the laser array. An array laser comprising a plurality of spaced lasing elements with an optical cavity for generating and propagating radiation under lasing conditions with each of the laser elements being optically uncoupled from one another is enhanced by an extended spectral emission linewidth and reduction in temporal coherence. This extended spectral emission linewidth and reduction in temporal coherence is accomplished by changing the gravity gain or loss for at least a majority of the laser elements relative to each other whereby a different longitudinal mode(s) of operation and frequency of operation exist for each such laser element.

Abstract: A two step annealing process is utilized for performing imputity induced disordering comprising an initial higher temperature, shorter term or rapid thermal anneal (RTA) treatment followed by a lower temperature, longer term or slow thermal anneal (STA) treatment. This two step impurity induced disordering (IID) anneal process enhances the amount of and depth of impurity species or diffusant penetration into the crystalline structure undergoing IID treatment. Also, it provides for improved accuracy in controlling the extend of impurity species concentration and the extent of its penetration into the cyrstalline structure so that resulting diffusion profiles in such structures can be systematically reproduced.

Abstract: A thin film bilayer composite source comprises a deposited impurity source layer, e.g. Si or Sb, heavily doped with a diffusion enabling agent, e.g. As, and capped with a passivating layer, e.g. Si.sub.3 N.sub.4, SiO.sub.2, AlN or SiO.sub.x N.sub.y. In a preferred embodiment, a thin film bilayer composite source comprises a Si layer on the surface of said structure vapor deposited at a temperature in excess of 500.degree. C. in the presence of a source of As to hevily dope the layer in the range of 5%-20% atomic weight and a thin cap layer of Si.sub.3 N.sub.4 deposited on the Si layer at a temperature in excess of 500.degree. C. having a thickness only sufficient to prevent the outdiffusion of Ga and As, which thickness may be about 400 .ANG.-700 .ANG.. An important aspect of the employment of this bilayer composite source as a diffusion source for III-V structures is that the composite source is initially deposited at high temperatures, above 500.degree.0 C., i.e.