Charlie S Zhang

US Patent:

6888980, May 3, 2005

Filed:

Dec 9, 2002

Appl. No.:

10/315899

Inventors:

Danny (Dejin) Yu - Fremont CA, US
Li Chen - Fremont CA, US
William (Wei) Yang - Fremont CA, US
Charlie (Shu) Zhang - Fremont CA, US
Jie Yang - Fremont CA, US

Assignee:

BaySpec, Inc. - Fremont CA

International Classification:

G02B006/28
G02B006/32
G02B006/34

US Classification:

385 24, 385 33, 385 37

Abstract:

A device for expanding the wavelength band of an optical component is disclosed. The device has a beam splitter for splitting a wavelength division multiplexed beam into two beams at a desired separation angle. An optical grating separates the two beams into spectral components for each beam. The spectral components are focused on a receiving surface. The separation angle between the two beams expands the wavelength band of the WDM signal.

US Patent:

6900932, May 31, 2005

Filed:

Sep 16, 2002

Appl. No.:

10/245458

Inventors:

Li Chen - Fremont CA, US
William Yang - Fremont CA, US
Charlie Zhang - Fremont CA, US
Danny Yu - Fremont CA, US

Assignee:

BaySpec, Inc. - Fremont CA

International Classification:

H01S003/00
G02B027/44

US Classification:

3593371, 359566

Abstract:

An optical gain flattening filter for attenuating the wavelength power levels of an optical beam to a threshold value. The filter has a series of volume phase gratings which each have a loss spectrum. The sum of the loss spectra for the volume phase gratings is about equal to the opposite of the gain spectrum of the optical amplifier. As the optical beam passes through the volume phase gratings, the sum of the loss spectra is added to the gain spectrum of the optical amplifier such that the optical beam is attenuated to the threshold value.

US Patent:

8514394, Aug 20, 2013

Filed:

Aug 9, 2010

Appl. No.:

12/853222

Inventors:

Wei Yang - Fremont CA, US
Ming Chai - Union City CA, US
Charlie Zhang - Fremont CA, US
Patrick Yang - Fremont CA, US

Assignee:

BaySpec, Inc. - Fremont CA

International Classification:

G01J 3/28

US Classification:

356328

Abstract:

A spectrograph having multiple excitation wavelength ranges is disclosed. The spectrograph can include a wavelength switching mechanism to switch between different wavelength ranges in accordance with the wavelength of an incoming light signal. The wavelength switching mechanism can include multiple optical assemblies (or elements) corresponding to the different wavelength ranges for processing the incoming light signal. The mechanism can also include a switching component for switching the optical assemblies to align the appropriate assembly with the incoming light signal. Each optical assembly can include one or more transmission gratings to disperse the incoming light signal into multiple wavelengths within a particular wavelength range and a reflecting mirror proximate to the grating(s) to reflect the wavelengths of light back through the grating(s) to photodetectors for measuring to wavelengths to generate a light spectrum. The spectrograph can be used in Raman spectroscopy.

US Patent:

20030118281, Jun 26, 2003

Filed:

Dec 6, 2002

Appl. No.:

10/313150

Inventors:

Li Chen - Fremont CA, US
Danny Yu - Fremont CA, US
William Yang - Fremont CA, US
Charlie Zhang - Fremont CA, US
Jie Yang - Fremont CA, US

International Classification:

G02B006/293
G02B006/34

US Classification:

385/024000, 385/037000

Abstract:

A device for expanding an operable wavelength band of an optical component is disclosed. The device has an optical grating configured to receive a wavelength division multiplexed optical signal. The optical grating is configured to separate the optical signal into two wavelength bands separated by a prescribed wavelength difference. The device has a focusing lens system to focus the two wavelength bands onto a receiving surface. The two wavelength bands are separated on the receiving surface by the prescribed wavelength difference in order to expand the wavelength band of the WDM signal.

US Patent:

20040105144, Jun 3, 2004

Filed:

Dec 3, 2002

Appl. No.:

10/310127

Inventors:

William Yang - Fremont CA, US
Li Chen - Fremont CA, US
Frank Levinson - Palo Alto CA, US
Danny Yu - Fremont CA, US
Charlie Zhang - Fremont CA, US
Chase Wang - Fremont CA, US
Wilson Liu - Fremont CA, US

International Classification:

H04B010/12

US Classification:

359/341410

Abstract:

An optical amplifier system for amplifying an input wavelength division multiplexed (WDM) optical signal with a first optical coupler to extract a portion of the power of the input signal, an erbium-doped fiber amplifier to generate an output signal and a second optical coupler to extract a portion of the power of the output signal. A spectral monitoring unit having a volume phase grating separates the extracted input and output signals into spectral components. A photo-detector array of the spectral monitoring unit determines the power level of the spectral components. The system further includes a controller operative to control the operation of the amplifier in response to the power levels of the spectral components.