David Sarnoff Research Center, Inc.

General Electric Company

Harvard College

Nils W Carlson

Gary A Evans

Thomas W Mossberg

Jacob M Hammer

Charlie J Kaiser

Michael Ettenberg

William R Babbitt

Yu-Sheng Bai

A semiconductor light emitter comprising a substrate of a semiconductor material having a pair of opposed surfaces and a body of semiconductor material on one of the surfaces. The body includes a pair of clad layers of opposite conductivity types having an intermediate quantum well region therebetween. The clad layers are of a semiconductor material which forms a heterojunction with the material of the quantum well region. The clad layers and the quantum well region form a waveguide which extends along the body. A plurality of gain sections are formed in the body spaced along and optically coupled by the waveguide. Each of the gain sections is adapted to generate light therein when a voltage is placed thereacross. One of the gain section has gratings at each end thereof which are adapted to reflect light back into the one gain section and thereby create a beam of light. The grating between the one gain section and an adjacent gain section is adapted to allow some of the light generated in the one gain section to pass therethrough along the waveguide to the next gain section. Each of the other gain sections have gratings adjacent an end opposite the first gain sections. The periods of the grating are such that no self-oscillation of the light in the waveguide occurs so that each of the other gain sections serve as single pass amplifiers. The gratings also direct the amplified light from the other gain sections out of the body.

Monolithic semiconductor light emitter and amplifier

An optical amplifier comprising a substrate of a semiconductor material having a pair of opposed surfaces and a body of semiconductor material on one of the surfaces. The body includes a pair of clad layers of opposite conductivity types having an intermediate quantum wall region therebetween. The clad layers are of a semiconductor material which form a heterojunction with the material of the quantum well region. The clad layers and quantum well region forms a waveguide which extends along the body. A gain section is in the body along the waveguide. The gain section includes a capping layer over the outermost clad layer, a contact on the capping layer and a contact on the other surface of the substrate to allow a voltage to be applied across the gain section. The gain section is adapted to generate light in the active region when a voltage is applied thereacross. A light input section having a grating extending across the body is at one end of the gain section. The light input section is adapted to direct light into the body and along the waveguide. A light output section having a grating extending across the body is at the other end of the gain section. The light output section is adapted to direct the amplified light from the gain section out of the body. The periods of the gratings are such that no self-oscillation of the light in the waveguide occurs.

Optical amplifier

A diode laser array comprises a substrate of a semiconductor material having first and second opposed surfaces. On the first surface is a plurality of spaced gain sections and a separate distributed Bragg reflector passive waveguide at each end of each gain section and optically connecting the gain sections. Each gain section includes a cavity therein wherein charge carriers are generated and recombine to generate light which is confined in the cavity. Also, the cavity, which is preferably a quantum well cavity, provides both a high differential gain and potentially large depth of loss modulation. Each waveguide has a wavelength which is preferably formed by an extension of the cavity of the gain sections and a grating. The grating has a period which provides a selective feedback of light into the gain sections to supporting lasing, which allows some of the light to be emitted from the waveguide normal to the surface of the substrate and which allows optical coupling of the gain sections. Also, the grating period provides an operating wavelength which is on the short wavelength side of the gain period of the gain sections required for laser oscillation. An RF pulse is applied so as to maximize the magnitude of the loss modulation and the differential gain in the gain sections. The array is operated by applying a DC bias to all the gain sections at a level just below the threshold of the gain sections to only one of the gain sections which raises the bias in all of the gain sections to a level that causes all of the gain sections to oscillate. Thus, a small bias can turn the array on and off.

Diode laser array

A superluminescent diode has one end coupled to a DBR having a grating and the other end has a reflective coating. A broadlight spectrum is emitted for reduced speckle interference and phase noise when used in applications such as a gyroscope. The diode can be of the 'P side down' type for good heat dissipation during continuous wave operation. Two gratings can be used in order to reduce beam divergence.

Grating-coupled surface-emitting superluminescent device

Cross-correlation or convolution or a succession of such operations is performed by exposing an inhomogeneously broadened material to optical radiation pulses modulated in accordance with the information to be cross-correlated or convoluted and detecting the resulting emitted radiation.

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Lawrenceville, NJ, United States of America

Nils W Carlson