Darius Subacius

US Patent:

6889011, May 3, 2005

Filed:

Nov 2, 2001

Appl. No.:

10/004332

Inventors:

John A. Fee - Garland TX, US
Darius Subacius - Allen TX, US
Brian T. Teipen - Richardson TX, US

Assignee:

MCI, Inc. - Ashburn VA

International Classification:

H04B010/12

US Classification:

398148, 398149, 398152, 398161, 398159

Abstract:

The present invention is directed to an integrated system for performing dispersion compensation on wavelength channels in WDM or DWDM transmissions. The system includes a tunable integrated dispersion compensation module that performs chromatic dispersion compensation and polarization mode dispersion compensation on each of the wavelength channels in the transmission. Feedback is used to adjust the tunable integrated dispersion compensation module until receiver performance is optimized.

US Patent:

7587049, Sep 8, 2009

Filed:

Dec 8, 2004

Appl. No.:

10/580959

Inventors:

Alexel Trifonov - Boston MA, US
Anton Zavriyev - Swampscott MA, US
Darius Subacius - Groton MA, US

Assignee:

MagiQ Technologies, Inc. - New York NY

International Classification:

H04L 9/00
H04K 1/00
G01B 9/02

US Classification:

380263, 380260, 380278, 380283, 380 44

Abstract:

A one-way stabilized QKD system () that utilizes a control signal (CS) and a quantum signal (QS) that travel the same path through the system from a first QKD station (Alice) to a second QKD station (Bob). The control signal is detected at Bob and used to stabilize Bob's side of the interferometer against phase variations. The system also includes a polarization control stage () that controls (e. g. , scrambles) the polarization of the photons entering Bob. The combination of the polarization control and the active phase stabilization of the interferometer at Bob's end allows for the stable operation of the interferometer when used as part of a one-way QKD system.

US Patent:

20030219256, Nov 27, 2003

Filed:

Aug 2, 2002

Appl. No.:

10/211709

Inventors:

Farhad Hakimi - Watertown MA, US
Hosain Hakimi - Watertown MA, US
Darius Subacius - Groton MA, US

International Classification:

H04B010/12

US Classification:

398/149000

Abstract:

An optical communication system and method are disclosed. Optical communication may be implemented with less complicated and costly components yet use RZ-like signal formats. The method may also be adapted to provide communication with beneficial phase relationships among optical pulses. An originating signal has a plurality of pulses, each pulse defined by a leading edge and a falling edge. A plurality of first optical pulses are created and transmitted on an optical communication medium in which each first optical pulse corresponds to a leading edge of a corresponding pulse of the originating signal. A plurality of second optical pulses are created and transmitted on an optical communication medium in which each second optical pulse corresponds to a falling edge of a corresponding pulse of the originating signal.

US Patent:

20080130888, Jun 5, 2008

Filed:

Sep 12, 2005

Appl. No.:

11/662560

Inventors:

Alexei Trifonov - Boston MA, US
Darius Subacius - Groton MA, US

International Classification:

H04K 1/00
H04L 9/00

US Classification:

380256, 380277

Abstract:

Methods and apparatus for generating coherent optical pulses (P, P) in a quantum key distribution (QKD) station (Alice-N) of a QKD system () without using an optical fiber interferometer () are disclosed. The method includes generating a continuous wave (CW) beam of coherent radiation (R) having a coherence length LC and modulating the CW beam within the coherence length. The invention obviates the need for an interferometer loop to form multiple optical pulses from a single optical pulse, thereby obviating the need for thermal stabilization of the interferometer loop at the QKD station Alice-N.

US Patent:

61884626, Feb 13, 2001

Filed:

Sep 2, 1998

Appl. No.:

9/145506

Inventors:

Oleg D. Lavrentovich - Kent OH
Darius Subacius - Kent OH

Assignee:

Kent State University - Kent MI

International Classification:

G02F 1133
G02F 1137

US Classification:

349201

Abstract:

The present invention is directed to liquid crystal diffraction gratings with electrically controlled periodicity. An electrical field is applied to liquid crystal device wherein the liquid crystals align to form a diffraction grating. The period of the diffraction grating is varied by changing the applied electrical field. The diffraction grating therefore has a period that can be varied by an electrical field.