Bogdan S Szafraniec

US Patent:

6486958, Nov 26, 2002

Filed:

Apr 24, 2001

Appl. No.:

09/841393

Inventors:

Bogdan Szafraniec - Sunnyvale CA
Douglas M. Baney - Los Alto CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01B 902

US Classification:

356451, 25022723, 359191

Abstract:

Heterodyne-based optical spectrum analysis involves filtering a heterodyne beat signal with at least one matched filter in order to improve the signal-to-noise ratio and the spectral resolution of the heterodyne-based optical spectrum analysis. In an embodiment, an input signal is combined with a swept local oscillator signal in an optical coupler. The combined optical signal is output to a receiver and a heterodyne beat signal is detected. The heterodyne beat signal is filtered by a matched filter unit and the filtered heterodyne beat signal is utilized to generate an output signal that is indicative of an optical parameter of the input signal. By utilizing the quadratic phase behavior of the heterodyne beat signal in signal processing, the resolution of a heterodyne-based OSA can be substantially improved over known heterodyne-based OSAs.

US Patent:

6515276, Feb 4, 2003

Filed:

Mar 17, 2001

Appl. No.:

09/811220

Inventors:

Douglas M. Baney - Los Altos CA
Bogdan Szafraniec - Sunnyvale CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

H04B 1018

US Classification:

25022719, 359124

Abstract:

A coherent optical spectrum analyzer is provided in which an optical balancing tone having a specific signature is injected into a signal path of a balanced optical receiver. A measuring unit is provided to analyze the balancing tone component in the signal output from the balanced optical receiver and determine characteristics of the optical receiver. A compensation unit is provided for providing compensation to counter, or negate any imbalances determined via the measuring unit. The balanced optical receiver is preferably a polarization state independent optical receiver.

US Patent:

6590666, Jul 8, 2003

Filed:

May 11, 2001

Appl. No.:

09/854070

Inventors:

Douglas M. Baney - Los Altos CA
Bogdan Szafraniec - Sunnyvale CA

Assignee:

Agilent Technologies Inc. - Palo Alto CA

International Classification:

G01B 902

US Classification:

356484

Abstract:

Heterodyne-based optical spectrum analysis involves measuring the sweep rate of a swept local oscillator signal and then generating an output signal that accounts for non-uniformities in the sweep rate of the swept local oscillator signal. In an embodiment, an input signal is combined with a swept local oscillator signal in an optical coupler and the sweep rate of the swept local oscillator signal is measured in a relative frequency measurement system. The combined optical signal is output from the optical coupler to a receiver and a heterodyne beat signal is generated. The heterodyne beat signal and measured local oscillator frequency sweep rate information are utilized by a signal processor to generate an output signal that is indicative of an optical parameter of the input signal and that accounts for non-uniformities in the sweep rate of the local oscillator signal. Because the actual sweep rate of the swept local oscillator signal is measured during analysis of the input signal, the horizontal scale accuracy of heterodyne-based OSAs is improved.

US Patent:

6671056, Dec 30, 2003

Filed:

Jan 11, 2001

Appl. No.:

09/759004

Inventors:

Bogdan Szafraniec - Sunnyvale CA

Assignee:

Agilent Technologies, Inc - Palo Alto CA

International Classification:

G02B 902

US Classification:

356484, 356477

Abstract:

An optical spectrum analyzer involves a swept local oscillator signal that is depolarized before the swept local oscillator signal is combined with an input signal. An embodiment of a system for optical spectrum analysis includes a depolarizer, an optical coupler, and a heterodyne receiver. The depolarizer has an input to receive a swept local oscillator signal and an output for outputting a depolarized swept local oscillator signal. The optical coupler has a first input and a second input, the first input receiving an input signal, the second input being optically connected to the depolarizer to receive the depolarized swept local oscillator signal. The optical coupler also has an output for outputting a combined optical signal that includes the input signal and the depolarized swept local oscillator signal. The heterodyne receiver has an input for receiving the combined optical signal from the optical coupler and an output for outputting an electrical signal representative of the combined optical signal. In an embodiment, the swept local oscillator signal is depolarized such that the average polarization state of the swept local oscillator signal contains no preferential polarization state.

US Patent:

6766115, Jul 20, 2004

Filed:

Aug 22, 2000

Appl. No.:

09/643374

Inventors:

Wayne V. Sorin - Mountain View CA
Douglas M. Baney - Los Altos CA
Bogdan Szafraniec - Sunnyvale CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

H04B 1000

US Classification:

398161, 398 9, 398 16, 398 33, 398 24, 398 27

Abstract:

A system for measuring optical characteristics of a multiport optical device uses optical heterodyne detection and known port-specific transmission delays to simultaneously monitor multiple ports of the multiport optical device with a single receiver. An embodiment of a system includes a splitter configured to split a swept optical signal into a reference signal and a test signal and a test system input, connectable to the multiport optical device, for transmitting the test signal to the multiport optical device. The test system also includes an optical combiner and a receiver. The optical combiner is connectable to the multiport optical device to receive a first portion of the test signal having a first port-specific transmission delay and to receive a second portion of the test signal having a second port-specific transmission delay. The optical combiner combines the first portion of the test signal having the first transmission delay and the second portion of the test signal having the second transmission delay with the reference signal. The receiver is connected to the optical combiner to detect a first optical heterodyne signal that is generated from the combined first portion of the test signal and the reference signal and to detect a second optical heterodyne signal that is generated from the combined second portion of the test signal and the reference signal.

US Patent:

6801319, Oct 5, 2004

Filed:

Jan 3, 2002

Appl. No.:

10/038131

Inventors:

Bogdan Szafraniec - Sunnyvale CA
Charles Lange - Glendale AZ
Andrew Kaliszek - Phoenix AZ

Assignee:

Honeywell International, Inc. - Morristown NJ

International Classification:

G01C 1964

US Classification:

356460

Abstract:

A fiber optic gyroscope (FOG) including a depolarizer having substantially equal first and second fiber segments of polarization maintaining (PM) fiber coupled to a single mode (SM) fiber loop. The first PM fiber segment includes sections of fiber connected together via a splice having an angle from about 35Â to 55Â between major axes of polarization of the sections which it connects. Similarly, the second PM fiber segment includes sections of fiber connected together via a splice having an angle from about 35Â to 55Â between major axes of polarization of the sections which it connects. The length of each fiber section is chosen to maintain the thermal and mechanical symmetry of the SM fiber loop.

US Patent:

6801320, Oct 5, 2004

Filed:

Oct 15, 2002

Appl. No.:

10/271048

Inventors:

Bogdan Szafraniec - Sunnyvale CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01B 902

US Classification:

356484, 356477

Abstract:

A heterodyne polarimeter is disclosed where a polarization state is measured by using a polarization diversity receiver employing a polarization beam splitter to output two heterodyne signals. The amplitude and relative phase of the two detected heterodyne signals uniquely determine the polarization state.

US Patent:

6813027, Nov 2, 2004

Filed:

Jan 14, 2002

Appl. No.:

10/046521

Inventors:

Bogdan Szafraniec - Sunnyvale CA
Ali Motamedi - Los Altos CA
Greg Douglas Van Wiggeren - Los Gatos CA

Assignee:

Agilent Technologies, Inc - Palo Alto CA

International Classification:

G01B 902

US Classification:

356477

Abstract:

The present invention relates to determination of a property of an optical device under test, e. g. the group-delay of the optical device under test, by: tuning an optical frequency of an optical beam, deriving a dependency of the optical frequency of the optical beam over a first time period t, deriving a dependency of the optical property of the device under test over a second time period t+t, synchronizing the time dependency of the optical frequency of the optical beam with the time dependency of the optical property of the device under test, and deriving the frequency dependency of the optical property of the device under test from the synchronized time dependencies.