Jds Uniphase Corporation

Other

Northern Telecom Limited

Jozef Finak

Yihao Cheng

Neil Teitelbaum

Douglas James Beckett

David M Adams

Bruce A Richardson

Richard D Habel

George Kovar

Robert A Bruce

Edmond J Murphy

The invention relates to optical communications using techniques for providing efficient high speed polarization bit interleaving. One common architecture for high-speed time-division-multiplexing employs two modulators having a same bit rate, wherein two separately modulated streams of data bits are combined into a high-speed single serial stream of data bits, instead of providing a single higher-cost higher-speed modulator. The present invention has found with the availability of fast data modulators, that polarization bit interleaving can be employed more efficiently for higher speed data transmission in optical network systems by providing an optical modulator including a single data modulator, rather than multiplexing different data streams from different modulators. The present invention provides an optical modulator for encoding data on orthogonally polarized alternate light pulses comprising: means for modifying a laser light beam to a pulse train at a first frequency; a data modulator for encoding signal data on the pulse train at a second data stream frequency where the second frequency is greater than or equal to the first frequency; means for rotating a polarization state of at least alternate light pulses of the pulse train to provide a data stream of orthogonally polarized alternate light pulses.

Optical modulator and method for polarization bit interleaving

A sleeve for retaining a plurality of optical fibers in a close or contacting relationship is provided. The sleeve has a bore receiving a number of optical fibers. The internal surface of the bore is such that when that number of optical fibers are contained therein the bore surface defines a perimeter substantially equally spaced about the external surfaces of the optical fibers. Advantageously the sleeve of the present invention may be sealed about the plurality of fibers by vitrification or adhesive to support the fibers or fiber ends without causing unequally distributed stress in the fibers. Signal quality is thus better assured.

Optical fibre sleeve

The present invention relates to a coupling element for coupling between optical elements, for instance a ferrule encased fiber end and a lens, two lenses, or filter and lens assemblies, which provides a reliable joint with a determined spacing and angular orientation between them if needed. Advantageously, the coupling in accordance with the present invention does not obscure optical transmission through the coupling with an epoxy layer. A stand off element is provided which has opposite reference surfaces for joining the end faces of the optical elements and a central aperture, slot or equivalent open area for light transmission. In use the open area is aligned, for example with the fiber end and the desired port in the lens. Adhesive connection can be provided between the opposite surfaces of the stand off element and the coupling end faces of the optical elements. No epoxy is applied over the open area. Other securing methods such as external securing elements can be used. Alignment is established by the planar surfaces of the stand off element. The separation between elements can be accurately established by selecting the desired thickness between faces of the stand off element. Alternatively, the surfaces of the stand off element may be angled to compliment the surfaces of the elements, or to provide an accurate angled coupling. Loss is reduced by not transmitting light through an epoxy layer.

Optical coupling system

A method of reducing thermally-induced emission wavelength shift in laser diodes. In addition to the conventional ridge contact for supplying the modulation current to the laser diode a second ridge contact is formed on the device. A compensation current of substantially the same frequency as the modulation current but having an opposite phase is applied to the second contact. This compensation current is selected to substantially neutralize the transient temperature variations due to changes in the modulation signal and result in a generally steady state thermal situation.

Method of reducing the thermally-induced shift in the emission

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Kanata, Canada

Jozef Finak