Patrick C Chou

US Patent:

6567167, May 20, 2003

Filed:

Feb 16, 2000

Appl. No.:

09/505313

Inventors:

Patrick C. Chou - Cambridge MA
Hermann A. Haus - Lexington MA

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G01J 400

US Classification:

356367, 356365, 356368, 356 731, 385 11, 385 28, 385 29, 385123, 359484

Abstract:

A real-time optical compensating apparatus reduces the PMD in an optical fiber by determining the principal states of polarization of the optical fiber and delaying one principal state of polarization with respect to the other.

US Patent:

6834134, Dec 21, 2004

Filed:

Mar 23, 2001

Appl. No.:

09/816937

Inventors:

Patrick C. Chou - Fremont CA
Harry L. T. Lee - Boston MA
Rajeev J. Ram - Boston MA
Hermann A. Haus - Lexington MA
Erich P. Ippen - Belmont MA

Assignee:

3M Innovative Properties Company - St. Paul MN

International Classification:

G02B 634

US Classification:

385 15, 385 37, 372 25, 372 28, 372 26, 398191, 398199, 398200, 359278, 359237

Abstract:

A method and apparatus are provided for generating short (e. g. , picosecond) pulses using a 2 section 1553 nm DBR laser without gain switching nor external modulation. The center wavelength of the DBR section is modulated at 0. 5 GHz to generate a constant amplitude frequency modulated optical wave Large group velocity dispersion is then applied with a chirped fiber Bragg grating to convert the FM signal to a pulse stream.

US Patent:

6859268, Feb 22, 2005

Filed:

Feb 15, 2001

Appl. No.:

09/785039

Inventors:

Patrick C. Chou - Fremont CA, US
John M. Fini - Cambridge MA, US
Hermann A. Haus - Lexington MA, US

Assignee:

Massachusetts Institute of Technology - Cambridge MA

International Classification:

G01N021/00

US Classification:

356 731

Abstract:

A real-time optical compensating apparatus reduces the PMD in an optical fiber by determining the principal states of polarization of the optical fiber and delaying one principal state of polarization with respect to the other.

US Patent:

20030202798, Oct 30, 2003

Filed:

Apr 29, 2002

Appl. No.:

10/134878

Inventors:

Patrick Chou - Fremont CA, US
Bogdan Hoanca - Anchorage AK, US

Assignee:

Phaethon Communications - Fremont CA

International Classification:

H04B010/00

US Classification:

398/159000

Abstract:

A parallel monitored and controlled optical PMD compensator comprises a branch optical signal split from an optical signal path. A polarization controller (PC) and differential group delay are disposed in each of the paths. A controller adjusts polarization compensation of the PCs in response to PMD dispersion of the branch optical signal. A PMD monitor is preferably disposed in the branch path providing a monitor signal to the controller for use in adjusting the PCs. A polarization rotator may inject a reference signal into the paths with the PC disposed in the branch path acting as a polarization scrambler. A state of polarization (SOP) of the reference signal may be monitored by polarimeters disposed in both paths and the SOP of the reference signal in the branch path may be provided to the controller for adjusting polarization compensation of the inline PC.

US Patent:

56235712, Apr 22, 1997

Filed:

Aug 29, 1995

Appl. No.:

8/521099

Inventors:

Patrick C. Chou - Cambridge MA
Charles H. Joyner - Middletown NJ
Martin Zirngibl - Middletown NJ

Assignee:

Lucent Technologies Inc. - Murray Hill NJ

International Classification:

G02B 6126

US Classification:

385130

Abstract:

A polarization compensated waveguide grating router is formed by reducing the thickness of the cladding material deposited over segments of waveguide cores to be on the order of the height of the vertical extension of the optical field of the waveguide. The resulting "air-patch" segments increase the birefringence in the patch segments of the waveguides. By using an air-patch length which is inversely proportional to the length of each waveguide, the correct phase relationship can be maintained between the different waveguides to produce an InP-based router which is polarization independent.

US Patent:

61954845, Feb 27, 2001

Filed:

Sep 22, 1999

Appl. No.:

9/401160

Inventors:

James F. Brennan - Austin TX
Dwayne L. LaBrake - Cedar Park TX
Patrick C. Chou - Cambridge MA
Hermann A. Haus - Cambridge MA

Assignee:

3M Innovative Properties Company - Saint Paul MN
Massachusetts Institute of Technology - Cambridge MA

International Classification:

G02B 634
H01S 300

US Classification:

385 37

Abstract:

A method and an apparatus for stretching an optical pulse and shaping its spectrum. The method includes the step of: providing a an optical fiber element having a first long length fiber Bragg grating having a refractive index perturbation of varying periodicity. The optical pulse is launched into the fiber Bragg grating, wherein the Bragg grating reflects the pulse in a chromatically dispersed output. The reflected output is coupled with an optical modulator programmed to temporally modify the amplitude of the chromatically dispersed output to attenuate selected optical frequencies in a desired pattern. The apparatus for stretching and arbitrarily shaping the spectrum of an optical pulse with a desired wavelength resolution. DELTA. lambda. sub. res includes a routing optical device and an optical fiber element having a Bragg grating. The routing optical device routs energy between different waveguides, and has an input port to receive the optical pulse.