David R Braun

US Patent:

6462823, Oct 8, 2002

Filed:

Apr 13, 2001

Appl. No.:

09/835269

Inventors:

David M. Braun - Santa Rosa CA
Benjamin S. Wheeler - Santa Rosa CA
Rance M. Fortenberry - Santa Rosa CA
Gregory S. Hill - Santa Rosa CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01B 902

US Classification:

356452, 356451

Abstract:

A wavelength meter for measuring the wavelength of an input light signal. The meter includes a beam splitter, a fixed mirror, and a moveable mirror, the beam splitter splits the input signal into a first input signal and a second input signal, the first and second input signals being reflected from the fixed and moveable mirrors, respectively, and being recombined by the beam splitter. The first reference light signal is reflected by the fixed mirror and the second reference light signal is reflected by the moving mirror, the beam splitter recombines the first and second reference light signals to form a combined reference light signal. The amplitude of the combined reference light signal is detected by a reference detector that generates a reference signal related to the amplitude of the combined reference light signal. The wavelength meter also includes a position circuit for generating a start signal indicating that the moveable mirror is at a first position relative to the fixed mirror and that the moveable mirror is moving in a first direction. A controller records a sequence of measurement signal values in response to the start signal and the reference signal.

US Patent:

6646740, Nov 11, 2003

Filed:

Sep 19, 2001

Appl. No.:

09/957696

Inventors:

David M. Braun - Santa Rosa CA
Paul Emerson Bussard - Santa Rosa CA
Roger L. Jungerman - Petaluma CA
Benjamin S. Wheeler - Bodega Bay CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01J 318

US Classification:

356334, 356328

Abstract:

An optical filter for generating a filter output signal from a filter input signal, the filter output signal consisting of light from the filter input signal in a predetermined bandwidth. The filter includes a grating, a first optical assembly and an optical signal path. A portion of the input signal traverses the optical signal path such that it is diffracted from the grating to form a first intermediate beam that is input to the first optical assembly, which generates a second intermediate beam therefrom. The second intermediate beam is directed back to the grating and is diffracted by the grating, a portion of the diffracted second intermediate beam forming a portion of the filter output signal. The second intermediate beam is the inverted image of the first intermediate beam, and hence, the second reflection from the grating compensates for the time dispersion introduced by the first reflection from the grating.

US Patent:

6654124, Nov 25, 2003

Filed:

Sep 21, 2001

Appl. No.:

09/962042

Inventors:

Michael B. North Morris - Santa Rosa CA
David M. Braun - Santa Rosa CA
Gregory S. Hill - Santa Rosa CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01B 902

US Classification:

356451

Abstract:

An interferometer system is used to detect a wavelength of an unknown signal. The interferometer system includes a fringe pattern detection system and a power detecting system. The fringe pattern detection system measures an interference fringe pattern of the unknown signal. The power detecting system measures relative power of the unknown signal before the unknown signal enters the fringe pattern detection system. The relative power of the unknown signal is used to compensate for modulation within the unknown signal.

US Patent:

7102755, Sep 5, 2006

Filed:

Feb 22, 2002

Appl. No.:

10/080845

Inventors:

David M Braun - Santa Rosa CA, US
Misty J Mesel - Santa Rosa CA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01B 9/02
H04J 1/16

US Classification:

356450, 370210, 356484, 359246, 359278, 250250

Abstract:

A method determines power of a modulated signal that is applied to a wavelength meter by summing bin values within a designated bin range of a frequency transformed interferogram representing the modulated signal and provided by the wavelength meter. In a first embodiment of the method, the bin range within which the bin values are summed is designated by mapping a series of signal characteristics indicative of the types of the modulated signals applied to the wavelength meter, to a series of bin spans within the frequency transformed interferograms that represent the modulated signals. The method then enables a selection of a signal characteristic from the series of signal characteristics to identify the modulated signal that is applied to the wavelength meter. In response to a selection, the bin values are summed within a bin range that is consistent with the mapping of the series of signal characteristics to the series of bin spans and that is positioned about a center bin of the frequency transformed interferogram. In a second embodiment of the method, the bin range within which bin values are summed is designated automatically based on attributes of the frequency transformed interferogram.

US Patent:

54348749, Jul 18, 1995

Filed:

Oct 8, 1993

Appl. No.:

8/134424

Inventors:

Julie E. Fouquet - San Carlos CA
David M. Braun - Santa Rosa CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H01S 310

US Classification:

372 20

Abstract:

The invention increases the tuning range of a laser by altering the output coupler reflectivity. In a first embodiment of the invention, the tuning range of an external cavity laser is increased by applying a substantially spectrally flat reflective coating to the front facet of a semiconductor laser which has higher reflectivity than the uncoated front facet. In addition to increasing the tuning range, the increased reflectivity of the front facet reduces the laser threshold current for all laser wavelengths. In a second embodiment of the invention, various complex coatings were applied to the output coupler to generate reflective characteristics that change according to wavelength. The complex coatings enhance reflectance at the edges of the laser tuning curve without adversely affecting the output power at the center wavelengths. This further increases the tuning range of the laser while simultaneously maintaining high output power for each selected output wavelength.

US Patent:

60756470, Jun 13, 2000

Filed:

Jan 30, 1998

Appl. No.:

9/016235

Inventors:

David M. Braun - Santa Rosa CA
Timothy L. Bagwell - Rohnert Park CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

G02B 2700
G02B 530
G01N 2125

US Classification:

359578

Abstract:

An optical spectrum analyzer includes a polarization modifier that eliminates polarization-dependent wavelength spreading, enabling the analyzer to have high signal selectivity and high measurement sensitivity. The polarization modifier spatially separates orthogonal polarization components of the applied optical signal into separate optical beams and rotates the relative polarization components of the beams so that the beams are incident on a tunable interference filter in a multipass configuration at a single polarization state. The optical beams are directed through regions of the interference filter which lie on a contour of substantially equal center wavelength so that each of the multiple passes through the interference filter provides for corresponding narrowing of the filter bandwidth. Narrow bandwidth and low insertion loss are maintained over a wide tuning range by tilting the interference filter about a tilt axis intercepting the regions of the interference filter that lie on a contour of substantially equal optical thickness.

US Patent:

50357700, Jul 30, 1991

Filed:

Oct 4, 1990

Appl. No.:

7/592716

Inventors:

David M. Braun - Santa Rosa CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H01L 21306
B44C 122

US Classification:

156643

Abstract:

Photodetectors having low reflectivity triangular groove, surface relief gratings on homogenous material or one layer of a heterostructure. Preferably, the photodetector is a PIN photodiode in which the p-type layer is triangularly grooved. The surface relief gratings have an optical repeat distance greater than the wavelenth of light which impinges on the photodetector surface. Thus, zero order backward diffracted waves are not coupled into optical reflections which would thereby decrease the optical return loss (ORL). Furthermore, the surface relief gratings have minimum side-wall angles to limit reflection at the heterostructure interfaces from contributing to the ORL. The side-angles of the gratings are chosen to ensure that the angle of the higher order backward diffracted wave is greater than the capture angle of an optical receiver into which the photodetector is incorporated. The free-space depth of the grooves is a half-wavelength of the light impinging on the photodetector. Additionally, a novel ion milling technique is disclosed.

US Patent:

60756322, Jun 13, 2000

Filed:

Nov 26, 1997

Appl. No.:

8/979463

Inventors:

David M. Braun - Santa Rosa CA

Assignee:

Hewlett-Packard Company - Palo Alto CA

International Classification:

H04J 1402

US Classification:

359124

Abstract:

An optical noise monitor measures noise power within narrow wavelength regions between channel signals of a dense wavelength division multiplexed (DWDM) signal. The noise monitor receives the DWDM signal and cascades the signal along a multipoint travel path where the signal is incident on a series of multi-pass filters. Each multi-pass filter selects a narrow, predefined wavelength region between channel signals of the DWDM signal. Noise power within the predefined wavelength region is detected and SNR is monitored by comparing the detected noise power to the power in the channel signal. According to a first preferred embodiment of the present invention, the noise monitor includes multi-pass filters that each have reflective surfaces to guide optical energy within a predefined wavelength region through multiple passes of an optical filter. According to a second preferred embodiment of the present invention, the noise monitor includes multi-pass filters each having a serial arrangement of multiple optical filters.