Mark E Kuznetsov

US Patent:

6339603, Jan 15, 2002

Filed:

Oct 25, 2000

Appl. No.:

09/696055

Inventors:

Dale C. Flanders - Lexington MA
Mark E. Kuznetsov - Lexington MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H01S 310

US Classification:

372 20, 372 43, 372 27, 372 32, 372 99, 372 98

Abstract:

A semiconductor tunable laser system includes a tunable Fabry-Perot cavity and a cavity length modulator, which controls an optical length of the cavity at least over a distance corresponding to the spacings between the longitudinal modes of the laser cavity. Thus, the tunable Fabry-Perot cavity allows the laser cavity to have gain at the desired wavelength of operation while the cavity length modulator tunes the cavity length such that a longitudinal cavity mode exists at the desired wavelength of operation. Also, in one embodiment, a wavelength locker system is further provides that has a differential wavelength filter, e. g. , stepped etalon, and a multi-element detector, e. g. , a quad-detector. The controller then modulators the Fabry-Perot cavity to control the wavelength in response to the signal received from the multi-element detector.

US Patent:

6459710, Oct 1, 2002

Filed:

Nov 7, 2000

Appl. No.:

09/707714

Inventors:

Peter S. Whitney - Lexington MA
Mark E. Kuznetsov - Lexington MA
Steven C. Fawcett - Stoneham MA
Mark R. Malonson - Merrimac MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H01S 313

US Classification:

372 2902, 372 29021, 372 36, 385 92

Abstract:

A semiconductor laser system includes a reflector on the lid that directs light emitted from the front facet to the monitoring diode. Thus, even when the diode is installed behind the semiconductor laser chip, and as a result receives back facet light, the ratio of front facet to back facet light received by the monitoring diode is increased due to the operation of the reflector. This configuration improves power tracking in Bragg grating stabilized semiconductor laser systems, for example.

US Patent:

6473234, Oct 29, 2002

Filed:

Feb 28, 2001

Appl. No.:

09/796146

Inventors:

Mark E. Kuznetsov - Lexington MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

G02B 528

US Classification:

359578, 359124, 359161

Abstract:

A tunable filter system comprises a signal source providing a WDM having multiple channels, or other signal requiring spectral analysis, within a spectral signal band. A reference signal source is also provided that generates a reference signal with spectral features, such as narrow spectral lines, that are located within a spectral reference band. A tunable filter functions as a band pass filter in transmission and a notch filter in reflection. It is controlled to filter both the reference signal and the WDM signal. A transmission detector is provided to detect the signal transmission through the tunable filter and a return detector is provided to detect the signal that is returned from the filter. Embodiments of the invention rely on a characteristic of a class of tunable filters, such as Fabry Perot etalons, in which light that is not transmitted through the filter is reflected. Thus, while the tunable filter appears as a band pass filter in transmission, it functions as a notch filter in reflection.

US Patent:

6549548, Apr 15, 2003

Filed:

Jan 23, 2001

Appl. No.:

09/768082

Inventors:

Mark E. Kuznetsov - Lexington MA
Peter S. Whitney - Lexington MA
Dale C. Flanders - Lexington MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H61S 313

US Classification:

372 32, 372 98

Abstract:

A wavelength measurement system uses birefringent material waveplate, thereby producing a substantially sinusoidal spectral response. As a result, the responses of multiple birefringent filters can be combined to yield a filter system with a periodic frequency response that has an additive wavelength resolution that is spectrally stable. That is, the wavelength measurement system does not have regions where wavelength resolution is degraded. In one implementation, a waveplate system is used, placed between two blocks of birefringent material and A quadrant detector is used to detect the intensities of the resulting four beams.

US Patent:

6810062, Oct 26, 2004

Filed:

Apr 11, 2001

Appl. No.:

09/833139

Inventors:

Mark E. Kuznetsov - Lexington MA

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H01S 308

US Classification:

372 92, 359528

Abstract:

An optical resonator is designed to suppress higher order transverse spatial modes. Higher order transverse modes in the inventive optical resonator are forced to be unstable, and ultimately achieving single transverse mode resonator operation. Specifically, the mirror shape or intracavity lens profile is tailored to bound the lower order modes while rendering the higher order modes unstable. This has application in MEMS/MOEMS devices by reducing side mode suppression ratio (SMSR) dependence on alignment tolerances, for example.

US Patent:

7061618, Jun 13, 2006

Filed:

Oct 17, 2003

Appl. No.:

10/688690

Inventors:

Walid A. Atia - Lexington MA, US
Dale C. Flanders - Lexington MA, US
Petros Kotidis - Framingham MA, US
Mark E. Kuznetsov - Lexington MA, US

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

G01B 9/02

US Classification:

356454, 356519

Abstract:

Integrated spectroscopy systems are disclosed. In some examples, integrated tunable detectors, using one or multiple Fabry-Perot tunable filters, are provided. Other examples use integrated tunable sources. The tunable source combines one or multiple diodes, such as superluminescent light emitting diodes (SLED), and a Fabry Perot tunable filter or etalon. The advantages associated with the use of the tunable etalon are that it can be small, relatively low power consumption device. For example, newer microelectrical mechanical system (MEMS) implementations of these devices make them the size of a chip. This increases their robustness and also their performance. In some examples, an isolator, amplifier, and/or reference system is further provided integrated.

US Patent:

7095776, Aug 22, 2006

Filed:

Mar 19, 2003

Appl. No.:

10/392357

Inventors:

Mark E. Kuznetsov - Lexington MA, US
Peter S. Whitney - Lexington MA, US
Dale C. Flanders - Lexington MA, US

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

H01S 3/08

US Classification:

372 98, 372101

Abstract:

A wavelength measurement system uses birefringent material waveplate, thereby producing a substantially sinusoidal spectral response. As a result, the responses of multiple birefringent filters can be combined to yield a filter system with a periodic frequency response that has an additive wavelength resolution that is spectrally stable. That is, the wavelength measurement system does not have regions where wavelength resolution is degraded. In one implementation, a waveplate system is used, placed between two blocks of birefringent material and. A quadrant detector is used to detect the intensities of the resulting four beams.

US Patent:

7157712, Jan 2, 2007

Filed:

Sep 29, 2004

Appl. No.:

10/953046

Inventors:

Dale C. Flanders - Lexington MA, US
Walid A. Atia - Lexington MA, US
Mark E. Kuznetsov - Lexington MA, US

Assignee:

Axsun Technologies, Inc. - Billerica MA

International Classification:

G01N 21/35

US Classification:

25033907, 372 20

Abstract:

An optical power control system for a semiconductor source spectroscopy system controls power fluctuations in the tunable signal from the spectroscopy system and thus improves the noise performance of the system. This general solution has advantages relative to other systems that simply detect reference power levels during the scan and then correct the detected signal after interaction with the sample by reducing the requirements for coordinating the operation of the sample detectors and power or reference detectors. The spectroscopy system comprises a semiconductor source and a tunable filter. The combination of the semiconductor source and tunable signal illuminate a sample with a tunable signal, being tunable over a scan band. The power control system comprises an amplitude detector system for detecting the power of the tunable optical signal and power control system for regulating the amplitude of the tunable optical signal in response to its detected power.