Patents by Inventor Franklin F. Tong

Franklin F. Tong has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5528616
    Abstract: 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.
    Type: Grant
    Filed: April 24, 1995
    Date of Patent: June 18, 1996
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey A. Kash, Bardia Pezeshki, Franklin F. Tong
  • Patent number: 5487120
    Abstract: 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.
    Type: Grant
    Filed: February 9, 1994
    Date of Patent: January 23, 1996
    Assignee: International Business Machines Corporation
    Inventors: Michael M. Choy, Paul E. Green, Jr., William E. Hall, Frank J. Janniello, Jeff K. Kravitz, Karen Liu, Rajiv Ramaswami, Franklin F. Tong
  • Patent number: 5422898
    Abstract: 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.
    Type: Grant
    Filed: October 29, 1993
    Date of Patent: June 6, 1995
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey A. Kash, David W. Kisker, Bardia Pezeshki, Franklin F. Tong
  • Patent number: 5357363
    Abstract: 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.
    Type: Grant
    Filed: September 24, 1993
    Date of Patent: October 18, 1994
    Assignee: International Business Machines Corporation
    Inventors: Chung-Sheng Li, Karen Liu, Harold S. Stone, Franklin F. Tong
  • Patent number: 5343542
    Abstract: 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.
    Type: Grant
    Filed: April 22, 1993
    Date of Patent: August 30, 1994
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey A. Kash, Bardia Pezeshki, Franklin F. Tong
  • Patent number: 5233453
    Abstract: 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.
    Type: Grant
    Filed: April 29, 1992
    Date of Patent: August 3, 1993
    Assignee: International Business Machines Corporation
    Inventors: Kumar N. Sivarajan, David G. Steinberg, Franklin F. Tong
  • Patent number: 5128798
    Abstract: 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.
    Type: Grant
    Filed: February 7, 1991
    Date of Patent: July 7, 1992
    Assignee: International Business Machines Corporation
    Inventors: Donald F. Bowen, Pierre A. Humblet, Franklin F. Tong