Eric K Swanson

US Patent:

6430201, Aug 6, 2002

Filed:

Dec 21, 1999

Appl. No.:

09/468192

Inventors:

Murat Azizoglu - North Billercia MA
Thomas Kong - Brookline MA
Eric A. Swanson - Acton MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

H04J 304

US Classification:

370535

Abstract:

Multiple gigabit Ethernet (GbE) and Fiber Channel (FC) signals are multiplexed and transported on a wavelength-division multiplexed (WDM) communications link using synchronous optical network (SONET) signaling. A transmitter decodes the 8b/10b encoded GbE/FC signals to reduce their respective signaling rates to no greater than the payload data rate of an OC- signal used on the link. The decoded signal are packetized into fixed-size packets in order to append a stream identifier used for de-multiplexing at the receive end. The packetized streams are multiplexed together and formatted into the OC- signal, which is transmitted over the communications link. A receiver de-multiplexes the received signal to obtain the packet streams, converts the packet streams to the corresponding decoded signals, and re-encodes each signal to re-create the original GbE/FC signals. A pair of interfaces can be arranged to provide independent adding or dropping of the GbE/FC signals that share the same wavelength.

US Patent:

6433904, Aug 13, 2002

Filed:

Jul 27, 1999

Appl. No.:

09/361927

Inventors:

Eric A. Swanson - Acton MA
Richard Barry - Brookline MA
Murat Azizoglu - North Billercia MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

H04J 1402

US Classification:

359133, 359110, 359124, 359161, 359173, 359181, 359187, 359188, 359194, 359195

Abstract:

Data transmission apparatus includes first and second optical transmitters coupled to an optical link. A forward error correction (FEC) coder is coupled to the input of the second optical transmitter. A first information signal having a first information rate is provided to the first optical transmitter, and a second information signal having a second information rate is provided to the second optical transmitter. The use of the FEC coder enables the second information signal to have a higher information rate than the first information signal, while simultaneously enabling the respective output power levels of the first and second optical amplifiers to be substantially equal. The data transmission apparatus achieves higher data transmission capacity while retaining compatibility with pre-existing fiber spans and amplifier nodes. An optical transmission system incorporates an optical transmitter and an optical receiver having certain transmission characteristics, such as output power level, decision threshold level, etc. , that are adjustable in response to bit error rate information.

US Patent:

6445939, Sep 3, 2002

Filed:

Aug 9, 1999

Appl. No.:

09/370756

Inventors:

Eric Swanson - Acton MA
Christopher L. Petersen - Carlise MA
Edward McNamara - Chelmsford MA
Ronald B. Lamport - Pelham NH
David L. Kelly - Westford MA

Assignee:

LightLab Imaging, LLC - Westford MA

International Classification:

A61B 500

US Classification:

600342, 600434, 385 33, 385 34

Abstract:

Ultra-small optical probes comprising a single-mode optical fiber and a lens which has substantially the same diameter as the optical fiber. The optical fiber and lens are positioned in a probe housing which is in the form of an insertional medical device such as a guidewire. Connector elements are provided to facilitate the attachment of the probe to an optical system and the quick disconnection of the probe from the optical system. The probe is used to obtain optical measurements in situ in the body of an organism and can be used to guide interventional procedures by a surgeon.

US Patent:

6456409, Sep 24, 2002

Filed:

Jul 16, 2001

Appl. No.:

09/906195

Inventors:

Jianying Zhou - Acton MA
Richard A. Barry - Brookline MA
Murat Azizoglu - North Billerica MA
Eric A. Swanson - Acton MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

H04J 1402

US Classification:

359124, 359161

Abstract:

A Dense Wavelength Division Multiplexed (DWDM) optical transmission system that compensates for unequal channel performance over an extended fiber transmission distance. The DWDM optical transmission system includes optical transmitters at a transmitter end of a transmission path for transmitting respective channels of information at different wavelengths, a first pre-emphasis device for performing a first pre-emphasis technique on the respective channels, an optical multiplexor for combining the respective channels into a multi-wavelength optical signal for transmission on a single transmission fiber, at least one optical amplifier for amplifying the optical signal along the path, at least one second pre-emphasis device disposed along the path for performing a second pre-emphasis technique on the respective channels, an optical de-multiplexor for separating the optical signal into its component channels, and optical receivers at a receiver end of the path for receiving and detecting the information carried by the respective channels. The first and second pre-emphasis techniques performed by the respective first and second pre-emphasis devices compensate for unequal channel performance along the transmission path over a desired fiber transmission distance.

US Patent:

6501551, Dec 31, 2002

Filed:

Oct 5, 1999

Appl. No.:

09/414293

Inventors:

Guillermo Tearney - Cambridge MA
Stephen A. Boppart - Boston MA
Brett E. Bouma - Boston MA
Mark Brezinski - Malden MA
Eric A. Swanson - Acton MA
James G. Fujimoto - Cambridge MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G01B 902

US Classification:

356477, 356479

Abstract:

An imaging system for performing optical coherence tomography includes an optical radiation source; a reference optical reflector; a first optical path leading to the reference optical reflector; and a second optical path coupled to an endoscopic unit. The endoscopic unit preferably includes an elongated housing defining a bore; a rotatable single mode optical fiber having a proximal end and a distal end positioned within and extending the length of the bore of the elongated housing; and an optical system coupled to the distal end of the rotatable single mode optical fiber, positioned to transmit the optical radiation from the single mode optical fiber to the structure and to transmit reflected optical radiation from the structure to the single mode optical fiber. The system further includes a beam divider dividing the optical radiation from the optical radiation source along the first optical path to the reflector and along the second optical path; and a detector positioned to receive reflected optical radiation from the reflector transmitted along the first optical path and reflected optical radiation transmitted from the structure along the second optical path. The detector generates a signal in response to the reflected optical radiation from the reference reflector and the reflected optical radiation from the structure, and a processor generating a image of the structure in response to the signal from the detector.

US Patent:

6504631, Jan 7, 2003

Filed:

Feb 17, 1999

Appl. No.:

09/251814

Inventors:

Richard A. Barry - Brookline MA
Naimish Patel - Massachusetts MA
Eric Swanson - Acton MA
Marc Robidas - Andover MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

H04B 1000

US Classification:

359125

Abstract:

A network including a control channel source node and a plurality of control channel destination nodes is interconnected by communications media in the form of a ring. The control and control channel destination nodes transfer information over a plurality of channels using wavelength-division multiplex techniques. The control channel source node transmits control information to all of the control channel destination nodes over a unitary control channel, and each of the control channel destination nodes drains off a portion of the energy of the signal comprising the control channel to facilitate decoding and processing of the control information contained therein. Each of the aspects, the control channel destination nodes can also generate status information for transfer to the control channel source node over the control channel. The control channel source node drains off the energy of the signal comprising the control channel to facilitate decoding and processing of the status information contained therein.

US Patent:

6552797, Apr 22, 2003

Filed:

Jul 13, 2001

Appl. No.:

09/907892

Inventors:

Eric A. Swanson - Acton MA

Assignee:

The United States of America as represented by the Secretary of the Air Force - Washington DC

International Classification:

G01B 902

US Classification:

356479, 356497

Abstract:

An invention pertaining to the measurement of the freezing point of substances using OCDR and OCT. technology.

US Patent:

6580531, Jun 17, 2003

Filed:

Dec 30, 1999

Appl. No.:

09/475836

Inventors:

Eric A. Swanson - Acton MA
Ruo Ding Li - Acton MA

Assignee:

Sycamore Networks, Inc. - Chelmsford MA

International Classification:

H04B 1004

US Classification:

359110, 359161, 359187

Abstract:

A method and apparatus for in-circuit biasing of a modulated laser and bit error rate testing of an optical transmitter and/or optical receiver under the control of a test controller. The test controller is communicably coupled to an interface of a module under test, as well as to external test equipment. The test controller modifies operational parameters of the modulated laser, in order to obtain a desired output power and to obtain a predetermined extinction ratio. The operational parameters of the laser include a laser bias current, an electro-absorption modulator offset bias current and a modulation depth. The disclosed test controller also determines whether the optical transmitter and/or receiver exhibit acceptable bit error rates. The disclosed test controller uses a variable optical attenuator, in combination with an erbium-doped fiber amplifier (EDFA) to control an optical signal to noise ratio for a signal terminating at either the transmitter or the receiver of the optical transceiver under test. The system measures a number of relatively low bit error rates corresponding to a number of generated signal to noise ratios and, based upon the measured values, projects a signal to noise ratio for a relatively low bit error rate so as to avoid the long period of time necessary to perform actual testing to acquire bit error rate information at high optical signal to noise ratios.