At&t Bell Laboratories

Amp LLC

Lytel Corporation

International Business Machines Corporation

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Eugene I Gordon

Robert J Nielsen

John W Stafford

Uri Levy

Ifay Fay Chang

Robert Louis Hartman

Stuart L Blank

Philip J Anthony

Franklin Richard Nash

Webster E Howard

Ronald I Feigenblatt

Dan Botez

An alignment fixture includes an optical bench 12 mounting a semiconductor laser 21, a monitor 23 of optical emission, a lens 27 focused for transmitting optical emission along an optical axis 43, a holder 26 mounting the lens 27, a pedestal 36 positioning a diaphragm 29 spaced for the lens 27, an optical fiber 45, a tube 49 surrounding the fiber 45 and joined to the fiber 45, a bushing 55 surrounding the tube 49 and joined to the optical bench 12, and a datum surface 16' on the bench 12 for aligning the lens 27 and the fiber 45 with the optical axis 43.

Optical bench for a semiconductor laser and method

A cathodoluminescent lamp in the form of a vacuum diode or triode uses a self-supporting YAG crystal as the light emitter. The crystal shape can be selected (spherical, slab, bar) for desired effect and light trapping is turned to advantage by selectively coating the crystal surface to provide for preferential light emission.

Cathodoluminescent garnet lamp

A mechanism for achieving single frequency output in a semiconductor laser diode is disclosed. In accordance with the invention, a conventional laser diode having an anti-reflection coating on its output facet is coupled to a single mode fiber output pigtail having an anti-reflection coating on its input facet. The anti-reflection coatings suppress Fabry-Perot type feedback which would normally be effective for a large number of wavelengths. The fiber includes a built-in distributed Bragg reflector grating, which grating is located just beyond the output fiber input facet. The grating supplies feedback that is effective only over a narrow wavelength band approximating the wavelength spacing between the actual longitudinal modes of the structure so that the laser produces only a single frequency output.

Hybrid distributed bragg reflector laser

High power semiconductor lasers which operate in the fundamental lateral and transverse mode are disclosed. Fundamental transverse mode behavior is well known by virtue of using a thin active layer. Fundamental lateral mode behavior in a wide double hetero-structure laser is achieved by selectively enhancing losses in the higher order lateral modes. Alternatively, a distributed feedback structure such as a grating may be used to achieve fundamental lateral mode operation in a wide double hetero-structure semiconductor laser.

High power semiconductor lasers

In contrast to existing light addressed light valves for projection displays which use a homogeneous CdS or Se photoconductive layer as the control element for a liquid crystal cell, a silicon photo-diode array is disclosed which makes an effective control element capable of applying a spatially varying AC voltage across a liquid crystal light valve. Writing may be done with a miniature CRT in an optical or electron excitation mode. It is shown that for a video mode the ratio of diode capacitance to liquid crystal cell capacitance associated with the diode, and the frequency of the applied square wave voltage, define the buildup or decay time of the liquid crystal cell voltage. Thus, the frequency of the applied AC voltage can be used to control sensitivity and transient response and there is no lag. The dynamic range of the cell voltage is shown to depend on the ratio of diode capacitance to liquid crystal cell capacitance. The display can be used in a storage mode by erasing with an AC voltage and writing with a constant voltage. The silicon photodiode array is compatible with a CCD frame store using direct minority carrer injection for writing. This light addressed version thus represents a desirable milestone in achieving an all solid-state projection display.

Light activated light valve with a silicon control element

A lens assembly 26 includes, a lens 27, an optical diaphragm 29 as a convex curved leaf spring, a pedestal 30 spacing the diaphragm 29 from the lens 27, and a holder for mounting the lens assembly 26 in desired position.

Lens assembly for optical coupling with a semiconductor laser

An optical fiber assembly 54 includes, an optical fiber 45, a tube 49 surrounding the fiber 45, a bushing 55 encircling the tube 49, a second tube 52 surrounding the fiber, and the fiber 45 is bent to a smoothly curved configuration within the confines of the tube 49 in relief of a column load applied on the fiber 45 by the tubes 49, 52.

Optical fiber assembly including means utilizing a column load to

An optoelectronics package 1 comprising, an optical bench 12 along which is defined an optical axis 43, a semiconductor laser 21 along the optical axis 43, a lens 27 focused on the laser 21 and transmitting optical emission from the laser 21 along the optical axis 43, an optical fiber 45 having an optical face 48 aligned with the optical axis 43, and the fiber 45 is secured to the optical bench 12 with a column load applied on the fiber 45.

Optoelectronics package for a semiconductor laser

A semiconductor laser diode comprising first and second parallel optically coupled waveguides is disclosed. The waveguides extend between first and second partially reflecting end facets. The first waveguide terminates at the first facet with a high reflection coating and at the second facet with an anti-reflection coating. The second waveguide terminates at the first facet with an anti-reflection coating and at the second facet with a high reflection coating. Thus, the feedback path for the laser involves portions of both waveguides and the coupling region therebetween. As a result, no standing waves are set up in either waveguide near the portions of the end facets which are anti-reflection coated and from which radiation is emitted so that processes which cause emitting facets to fail at high powers are mitigated. When the two waveguides are slightly different geometrically and are coupled by a periodic structure, laser oscillations are sustainable only in a narrow frequency band centered about a frequency which is relatively insensitive to changes in pumping current so that the laser may be directly modulated with a relatively small FM to AM ratio.

Dual channel fabry-perot laser

The present invention is a semiconductor diode laser array which favors oscillation in the zero degree phase shift mode. The array comprises first and second sets of waveguides which are interdigitated in a coupling region. Energy transfer between the first and second sets of waveguides by way of evanescent coupling is needed to define the feedback paths for sustaining laser oscillations in the waveguides. Such coupling is optimum and the threshold current for lasing lowest when all of the waveguides in both sets oscillate in phase.

Phase locked diode laser array

Room temperature laser action is achieved in a cathode ray tube (CRT) in which the target includes a plurality of semiconductor layers: a thin, wide bandgap buffer layer; a thicker, narrow bandgap active layer; and a much thicker wide bandgap cavity-length-adjusting layer. The light beam direction is essentially parallel to the e-beam direction and hence is scannable.

Method of making a semiconductor laser CRT

A channel add/drop filter-coupler includes two single-mode optical fibers that have different refractive index profiles. Each optical fiber has a propagation constant that is a function of frequency. A portion of the cladding of each fiber is removed to form a planar surface on each fiber. A plurality of channels is formed in one or both of the planar surfaces. The channels are spaced with a predetermined channel period that is inversely proportional to the difference between the propagation constants of the two fibers of the filter-coupler at the desired center frequency of the filter-coupler. The filter-coupler is completed by joining the two fibers at the planar surfaces. The coupling of the filter-coupler may be tuned by moving one fiber longitudinally, angularly, or, preferably, laterally with respect to the other fiber. Furthermore, the filter response of the filter-coupler is advantageously shaped by varying the location of the channels within the predetermined channel periods or by varying the depth or the width of the channels.

Channel add/drop filter-coupler

To achieve a high power, large area, substantially monochromatic solid-state light source, the outputs of hundreds of discrete injection lasers are combined. For the combination, each laser is butt coupled to one end of its separate large core multimode fiber. Groups of fibers are packaged in linear arrays in separate ribbon cables and the ribbon cables are stacked in a two-dimensional rectangular array. The free ends of the fibers terminate in a common plane to make available, at such plane, a high power, large area, source of light. In one embodiment, separate fibers are coupled to the two ends of each injection laser to utilize the light emitting at both facets of the laser.

High power, broad area, monochromatic light source

In a CRT display device the target comprises a multilayered semiconductor including a p-n junction and at least one current-blocking layer. The e-beam is locally absorbed in the current-blocking layer so as to open a narrow zone which allows charge to flow through the forward biased p-n junction. The injection current produces a local spot of light which radiates from the opposite side of the device and whose position is varied by scanning the e-beam. In one embodiment the current-blocking layer is a semi-insulating semiconductor layer, and in another embodiment the current-blocking layer comprises the base of a normally cut-off transistor.

Growing community of inventors

Convent Station, NJ, United States of America

Eugene I Gordon