Blueleaf, Inc.

Picarro, Inc.

Marc Levenson

Barbara A Paldus

Bruce A Richman

Alexandre Katchanov

Daniele Romanini

Arnaud Garnache

Frederic Stoeckel

Guido Knippels

Christopher Rella

Robert Lodenkamper

Robert Lodenkemper

Acousto-optical filter systems for filtering a light beam by generating undiffracted and diffracted light beams within a birefringent crystal and by suppressing the diffracted beam within or at a face of the crystal. Where the two beams are noncollinear, an aperture provides diffracted beam suppression. Where the two beams have different polarization directions, the diffracted beam is suppressed by a polarization analyzer, internal reflection of each beam at a Brewster angle at the surface, total internal reflection of the diffracted beam at the surface, or a suitably oriented multilayer thin film at the surface. Variation of the acoustic frequency provides tunability of the filter.

Modified tunable acousto-optic filter

An optical fiber transmitter for emitting an information-carrying laser beam comprises an optically or electrically pumped single mode MQW (multi-quantum well) semiconductor amplifying mirror as a gain medium and a separate external reflector to form a cavity. The external cavity length defines a comb of optical modes, all or a subset of which correspond to channel wavelengths of an optical telecommunications system having plural optical channels. The semiconductor gain element has a homogeneously broadened gain region; a tuning arrangement tunes the laser from mode to mode across the gain region, thereby selecting each one of the plural optical channels. When the maximum gain bandwidth is less than mode-to-mode spacing defined by the cavity, the tuning arrangement includes a means of altering the temperature of the amplifying mirror, thereby translating the frequency of the gain peak from one mode to another. An optical modulator adds modulation to provide an information-carrying laser beam, and a coupler couples the information-carrying laser beam into an optical fiber of the optical telecommunications system. A calibration method based on detecting inter-mode optical transitions (mode hopping) is described. The parameters of the amplifying mirror and tuning arrangement can be adjusted during operation to switch quickly from one cavity mode to another in stepwise fashion.

Optical transmitter comprising a stepwise tunable laser

An optical fiber transmitter for emitting an information-carrying laser beam comprises an optically or electrically pumped single mode MQW (multi quantum well) semiconductor amplifying mirror as a gain medium and a separate external reflector to form a cavity. The external cavity length defines a comb of optical modes, all or a subset of which corresponding to channel wavelengths of an optical telecommunications system having plural optical channels. The semiconductor gain element has a homogeneously broadened gain region; a tuning arrangement tunes the laser from mode to mode across the gain region thereby selecting each one of the plural optical channels. When the maximum gain bandwidth is less than mode-to-mode spacing defined by the cavity, that tuning arrangement comprises a means of altering the temperature of the amplifying mirror, thereby translating the frequency of the gain peak from one mode to another. An optical modulator adds modulation to a beam emitting from the laser to provide the information-carrying laser beam, and a coupler couples the information-carrying laser beam into an optical fiber of the optical telecommunications system. A calibration method based on detecting inter-mode optical transitions (mode hopping) is described. The parameters of the amplifying mirror and tuning arrangement can be adjusted during operation to switch quickly from one cavity mode to another in stepwise fashion.

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Campbell, CA, United States of America

Marc Levenson