International Business Machines Corporation

Franklin F Tong

Karen Liu

Jeffrey Alan Kash

Bardia Pezeshki

Chung-Sheng Li

William Eric Hall

Rajiv R Ramaswami

Frank J Janniello

Jeff Kenneth Kravitz

Paul Eliot Green, Jr

Michael M Choy

Pierre A Humblet

Harold S Stone

Kumar N Sivarajan

Weyl-Kuo Wang

David G Steinberg

Donald F Bowen

David W Kisker

A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs. Each IOC is associated with one of a plurality of communications channels and includes an I/O specific media connector (30) that is coupled to an appropriate transmitter (Tx) and receiver (Rx). The I/O specific media connector, Tx and Rx are constructed and operated in accordance with the specific data stream type that is input to and output from the associated channel of the WDM. By example, a first data stream may be conveyed through an optical (fiber) conductor in accordance with an ESCON protocol at 200 Mb/s, and a second data stream may be conveyed through an electrical (copper) conductor in accordance with an ECL non-specific protocol at up to 622 MB/s.

Optical wavelength division multiplexer for coupling to data sources and

This invention provides methods and apparatus for achieving wavelength sorting multiplexer/demultiplexer and its application to the implementation of planarized dynamic wavelength routing. Using integrated arrayed-waveguide gratings, sorting can be achieved by two configurations. In the first configuration channel wavelengths are properly selected and launched into prearranged input waveguides of an arrayed-waveguide grating such that channels at the same wavelength and from all inputs will be demultiplexed and routed to adjacent outputs. Operated in the reverse direction, the same device becomes a sorting multiplexer. The second configuration achieves wavelength sorting by using the cascade of multiple arrayed-waveguide gratings and can also be operated as a demultiplexer or a multiplexer. Combined with space switches, the wavelength sorting multi/demultiplexer are utilized to implement the planarized channel-selective dynamic wavelength router. The function of wavelength sorting eliminates on-chip waveguide crossings and therefore reduces losses and crosstalks. The sorting demultiplexer and multiplexer can further be implemented with a single arrayed-waveguide grating.

Wavelength sorter and its application to planarized dynamic wavelength

An apparatus is described for obtaining single frequency laser operation in a coupled waveguide configuration without using a diffraction grating. More specifically, this invention is a laser structure for oscillating light in single longitudinal mode. This structure has a pair of coupled but dissimilar waveguides that are collinear with each other and separated by a mirror in contact with each of the guides. The length of the waveguides are adjusted so that frequency selective coupling between the waveguides can discriminate between wavelengths corresponding to different longitudinal modes.

Asymmetric dual waveguide laser

A monolithically integrated equalization optical equalization device having an optical demultiplexer for demultiplexing an optical signal into a number of individual channels and a number of optical connections for connecting the terminals of the demultiplexers to an optical multiplexer. Metallic strips of varying lengths are deposited on the optical connections so that the optical signal is equalized over the channels at the output terminals of the optical multiplexer.

Gain equalization using monolithic planar waveguide grating multiplexer

A wavelength division multiplexer (WDM) unit (12) includes a plurality of Input/Output cards (IOCs 14). Each IOC is bidirectionally coupled to I/O specific media (fiber or copper) and to two coaxial cables. Also bidirectionally coupled to the coaxial cables are a plurality of Laser/Receiver Cards (LRC 20). The interface between the IOCs and the LRCs is an Emitter Coupled Logic (ECL) electrical interface that is conveyed over the coaxial cables. Each LRC is bidirectionally coupled by two single mode fibers to an optical multiplexer and demultiplexer, embodied within a grating (24). An input/output port of the grating is coupled to a fiber link (28) that enables bidirectional, full duplex data communications with a second WDM. Each WDM also includes a Diagnostic Processor Card (DPC 28) that receives status signals from the IOCs and LRCs, that forwards the status signals on to an external processor, and which generates control information for the IOCs and LRCs.

Optical wavelength division multiplexer for high speed,

This invention covers an apparatus for generating multiple wavelengths of light, where the intensity of each wavelength is separately controlled, and where all the wavelengths exit the device from the same aperture. Structurally, this multiple wavelength source consists of a passive waveguide coupled to an active tapered resonator. The light generated in the resonator couples to the passive waveguide and exits from the ends of the device. By pumping different regions of the resonator, different wavelengths can be obtained.

Tapered Fabry-Perot multi-wavelength optical source

The invention is a system and method for improving the signal-to-noise ratio of an electrical data signal transmitted between two electronic modules. An electrical data signal from a first module is amplified by an electrical amplifier to produce an amplified electrical data signal. The electrical amplifier is supplied by a power distribution network. The amplified electrical data signal has a power level sufficiently low such that the electrical amplifier does not cause significant disturbances in the power distribution network so that a plurality of the electrical amplifiers can be proximately located and operated concurrently without significant noise coupling occurring between the electrical amplifiers through the power distribution network. The electrical data signal is then converted to an optical data signal for transmission to a second module. The optical data signal is transmitted to the second module through an optical path where it is optically amplified. The amplified optical data signal is then received at the second module and detected to produce an electrical signal which has a substantially improved signal-to-noise ratio.

Interconnections having improved signal-to-noise ratio

This invention covers apparatus for providing a compact, high resolution waveguide optical demultiplexer or spectrometer for application in optical communications. With this invention, incoming light composing many discrete wavelengths or optical channels is spectrally resolved by the waveguide demultiplexer such that the wavelength channels are separated spatially. The two major elements of this invention are a waveguide having a partial mirror along its length to reflect optical frequencies therein, and an optical resonator where one of its resonating mirrors is the partial mirror of the waveguide. Selected frequencies are then extracted from the waveguide and resonated in the resonator.

Tapered fabry-perot waveguide optical demultiplexer

This invention discloses a method and apparatus for providing high speed optical tuning. With this invention, light is spatially routed through a tree of optical switches interconnected by waveguides to a selected fixed tuned optical filter in an array of such filters. Each of the optical switches can be controlled by a binary signal thereby permitting digitally controlled optical filtering.

Space-division switched waveguide array filter and method using same

Apparatus is described for achieving wavelength selection. Furthermore, the apparatus exhibits very high wavelength resolution, stable operation and rapid returning. A bundle of multi-wavelength light, entering the device, is acoustooptically deflected. This is done by driving two orthogonal acoustic transducrs of the deflector with two suitable frequencies fx and fy. The light so deflected passes first through a wedge etalon having a taper along the X-axis and then through a second wedge etalon having a taper along the Y-axis. The pair of wedges forms two, single-cavity etalons. Depending on the choice of fx and fy, any wavelength within the wavelength range covered by the two, single-cavity etalons can be selected rapidly and accurately.

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Stamford, CT, United States of America

Franklin F Tong