Patents by Inventor Christopher Anthony Park
Christopher Anthony Park has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6961128Abstract: An apparatus for detecting cross-talk and method therefore, wherein a first and a second output signal from a wavelength selective device are directed to be coincident upon a photodetector. A homodyne beat signal results from the coincidence of the first and the second output signal and the homodyne beat signal is used to measure wavelength drift.Type: GrantFiled: December 20, 2002Date of Patent: November 1, 2005Assignee: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Patent number: 6919963Abstract: A laser wavelength locking control loop apparatus comprising a wavelength selective device and a photodetector, coupled to a feedback controller circuit. Electromagnetic radiation emitted by the laser device is provided to the wavelength selective device which provides a first output signal at a first wavelength and a second output signal at a second wavelength. The first and second output signals are directed to the photodetector so as to coincide when incident thereupon. A beat signal results from the coincidence of the first and second output signals and this is used to measure wavelength drift.Type: GrantFiled: December 20, 2002Date of Patent: July 19, 2005Assignee: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Patent number: 6882780Abstract: An optical device having a photonic band gap element operative such that the refractive index can be varied through application of an electrical signal. This enables the manufacture of tuneable lasers, optical add/drop multiplexers and tuneable optical wavelength converters.Type: GrantFiled: September 17, 2002Date of Patent: April 19, 2005Assignee: Agilent Technologies, Inc.Inventors: Christopher Anthony Park, Richard Mark Ash, Andrew Thomas Harker, Paul Marshall Charles
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Patent number: 6778577Abstract: Controlling or stabilising the lasing wavelength of a source of laser radiation, wherein the source of laser radiation comprises a semiconductor material laser, a substrate to which the laser is mounted, a resonant optical cavity within the semiconductor material, the cavity having an active medium for generating laser radiation and one or more gaps in the semiconductor material within the cavity, wherein the substrate is deformable by the application of a mechanical stress to vary the size of the gap(s) in order to change the optical size of the gap(s) and hence to vary the wavelength of laser radiation generated by the semiconductor laser.Type: GrantFiled: January 21, 2003Date of Patent: August 17, 2004Assignee: Agilent Technologies, Inc.Inventors: Richard Mark Ash, Christopher Anthony Park
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Patent number: 6717710Abstract: An electro-modulating device for modulating light from a light source, as part of an opto-electronic communication network has a modulating medium for modulating light passing therethrough by varying an electric field applied across the modulating medium, an optical input-output surface, a light reflector, and electrodes for applying the varying electric field across the modulating medium. The input-output surface, the medium and the reflector are arranged so that light enters the medium through the input-output surface, travels through the medium towards the reflector, is reflected by the reflector to travel back through the medium towards the input-output surface, and exits the medium through the input-output surface. The electric field is transverse to light traversing the medium between the input-out surface and the reflector, to make it easier to couple an optic fiber to the input-output surface of the modulating medium.Type: GrantFiled: January 14, 2002Date of Patent: April 6, 2004Assignee: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Patent number: 6717709Abstract: An electro absorption modulator in which the photocurrent generated by the absorption of light is monitored and the bias voltage applied to the electro absorption modulator is varied in order to vary the photocurrent and thence the extinction ratio of the electro absorption modulator.Type: GrantFiled: July 17, 2002Date of Patent: April 6, 2004Assignee: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Publication number: 20030142709Abstract: The present invention relates to the control or stabilisation of the lasing wavelength of a source of laser radiation (8), comprising a semiconductor material laser (2), a substrate (4) to which the laser (2) is mounted, a resonant optical cavity (15) within the semiconductor material (16,18,20), the cavity (15) having an active medium (16) for generating laser radiation (8) and one or more gaps (28) in the semiconductor material (16,18,20) within the cavity (15), wherein the substrate (4) is deformable by the application of a mechanical stress (14) to vary the size of said gap(s) (28) in order to change the optical size of said gap(s) and hence to vary the wavelength of laser radiation (8) generated by the semiconductor laser (2).Type: ApplicationFiled: January 21, 2003Publication date: July 31, 2003Applicant: Agilent Technologies, Inc.Inventors: Richard Mark Ash, Christopher Anthony Park
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Patent number: 6590693Abstract: The present invention relates to a modulated light source, in particular for use as part of an opto-electronic communication network. The modulated light source has a laser and an external electro-optic modulator for modulating the intensity of light produced by the laser. A temperature sensor senses the temperature of the laser and the modulator. A control circuit connected to the temperature sensor adjusts the bias on the modulator so that the band edge of the modulator follows the changes in wavelength of the laser as the laser warms up during operation. This avoids the need for a cooling element to keep the temperature of the laser constant.Type: GrantFiled: May 16, 2001Date of Patent: July 8, 2003Assignee: Agilent Technologies, Inc.Inventors: Richard Mark Ash, Christopher Anthony Park, Andrew Thomas Harker
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Publication number: 20030123065Abstract: In an optical communications system employing a Wavelength Division Multiplexing (WDM) scheme, a laser device can be used to transmit electromagnetic radiation at different wavelengths, each different wavelength being known as a channel. In addition, a demultiplexer such as an Arrayed Waveguide Grating (AWG) can be used to separate out a multiplexed signal into its component channels. It is known that laser devices and AWGs are susceptible to wavelength drift as their temperatures change or aging occurs, in the case of the AWGs causing channels to overlap which results in cross-talk between adjacent channels. Consequently, the present invention provides an apparatus for detecting cross-talk and method therefor. To this end, a first and a second output signal from a wavelength selective device (9) are directed to be coincident upon a photodetector (11). A homodyne beat signal results from the coincidence of the first and the second output signal and the homodyne beat signal is used to measure wavelength drift.Type: ApplicationFiled: December 20, 2002Publication date: July 3, 2003Applicant: Agilent Technologies UK Limited to: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Publication number: 20030123066Abstract: In an optical communications network employing a wavelength division multiplexing (WDM) system, different wavelengths of electromagnetic radiation are used to transmit different signals. Because the wavelength of electromagnetic radiation that a laser device emits can drift as the temperature of the laser device changes, channels can overlap causing cross-talk. Consequently, the present invention provides a laser wavelength locking control loop apparatus (5) comprising a wavelength selective device (9) and a photodector (11), coupled to a feedback controller circuit (13). Electromagnetic radiation emitted by the laser device (7) is provided to the wavelength selective device (9) which provides a first output signal at a first wavelength and a second output signal at a second wavelength. The first and second output signals are directed to the photodetector (11) so as to coincide when incident thereupon.Type: ApplicationFiled: December 20, 2002Publication date: July 3, 2003Applicant: Agilent Technologies UK Limited to: Agilent Technologies Inc.Inventor: Christopher Anthony Park
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Publication number: 20030103255Abstract: An electro absorption modulator in which the photocurrent generated by the absorption of light is monitored and the bias voltage applied to the electro absorption modulator is varied in order to vary the photocurrent and thence the extinction ratio of the electro absorption modulator.Type: ApplicationFiled: July 17, 2002Publication date: June 5, 2003Applicant: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Publication number: 20030081641Abstract: An optical device comprising a photonic band gap element operative such that the refractive index can be varied through application of an electrical signal. This enables the manufacture of tuneable lasers, optical add/drop multiplexers and tuneable optical wavelength converters.Type: ApplicationFiled: September 17, 2002Publication date: May 1, 2003Applicant: Agilent Technologies, Inc.Inventors: Christopher Anthony Park, Richard Mark Ash, Andrew Thomas Harker, Paul Marshall Charles
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Publication number: 20020114055Abstract: This relates to an electro-modulating device (10) for modulating light from a light source, as part of an opto-electronic communication network. The electro-modulating device (10) has a modulating medium (16) for modulating light passing therethrough by varying an electric field applied across the modulating medium (16), an optical input-output surface (21), a light reflector (28), and electrodes (15, 17) for applying the varying electric field across the modulating medium (16). The input-output surface (21), the medium (16) and the reflector (28) are arranged so that light enters the medium (16) through the input-output surface (21), travels through the medium (16) towards the reflector (28), is reflected by the reflector (28) to travel back through the medium (16) towards the input-output surface (21), and exits the medium (16) through the input-output surface (21).Type: ApplicationFiled: January 14, 2002Publication date: August 22, 2002Applicant: Agilent Technologies, Inc.Inventor: Christopher Anthony Park
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Publication number: 20020075549Abstract: The present invention relates to a modulated light source (10), in particular for use as part of an opto-electronic communication network. The modulated light source (10) has a laser (12) and an external electro-optic modulator (16) for modulating the intensity of light produced by the laser (12). A temperature sensor (30) senses the temperature of the laser (12) and the modulator (16). A control circuit connected to the temperature sensor (30) adjusts the bias on the modulator (16) so that the band edge of the modulator follows the changes in wavelength of the laser (12) as the laser (12) warms up during operation. This avoids the need for a cooling element to keep the temperature of the laser (12) constant.Type: ApplicationFiled: May 16, 2001Publication date: June 20, 2002Inventors: Richard Mark Ash, Christopher Anthony Park, Andrew Thomas Harker
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Patent number: 6055102Abstract: An optical isolator (1) includes an isolator element (4) having an optical axis and a Faraday rotator (6) and at least one polarizer (7a, 7b) and a magnet (2). The magnet (2) is an open-core magnet shaped so that when placed on a substantially planar surface an orifice (3) is defined by the magnet (2) and the substantially planar surface. The isolator element (4) is located within the orifice so that the optical axis passes through the orifice. Such an isolator is well adapted for use in semiconductor laser modules.Type: GrantFiled: September 24, 1998Date of Patent: April 25, 2000Assignee: Hewlett-Packard CompanyInventor: Christopher Anthony Park