Patents by Inventor Stephen J. Mihailov
Stephen J. Mihailov 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: 10156680Abstract: An apparatus for use with a pulsed laser source for forming an optical grating in a target includes an adjustable telescope having an element with a negative optical power, for generation of a diverging optical beam, so that the optical beam has adjustable divergence upon exiting the telescope while focusing of light inside the telescope is avoided. A transmission diffraction grating is disposed in the optical beam exiting the telescope, for forming an optical interference pattern on the target. Optical gratings with different grating periods may be formed by adjusting the divergence of the optical beam exiting the telescope. Lack of tight focal spots inside the telescope enables use of ultrashort pulse duration, high peak intensity laser sources.Type: GrantFiled: July 10, 2015Date of Patent: December 18, 2018Assignee: National Research Council of CanadaInventors: Dan Grobnic, Stephen J. Mihailov, Robert B. Walker, Ping Lu, Huimin Ding, David Coulas
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Publication number: 20170192168Abstract: An apparatus for use with a pulsed laser source for forming an optical grating in a target includes an adjustable telescope having an element with a negative optical power, for generation of a diverging optical beam, so that the optical beam has adjustable divergence upon exiting the telescope while focusing of light inside the telescope is avoided. A transmission diffraction grating is disposed in the optical beam exiting the telescope, for forming an optical interference pattern on the target. Optical gratings with different grating periods may be formed by adjusting the divergence of the optical beam exiting the telescope. Lack of tight focal spots inside the telescope enables use of ultrashort pulse duration, high peak intensity laser sources.Type: ApplicationFiled: July 10, 2015Publication date: July 6, 2017Inventors: Dan GROBNIC, Stephen J. MIHAILOV, Robert B. WALKER, Ping LU, Huimin DING, David COULAS
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Patent number: 8768121Abstract: A filter and a method of filtering a high frequency electrical signal using photonic components is disclosed. The filter has a serially fiber-coupled laser source, a modulator, a filter, and a photodetector. The electrical signal is applied to the modulator. The modulated light propagates through the filter which is constructed to pass not only a modulated sideband, but also at least a fraction of light at the carrier frequency of the laser. The photodetector detects a signal at the beat frequency between the carrier and sideband signals, after both signals have propagated through the filter. As a result, a separate optical branch for light at the carrier frequency is not required, which considerably simplifies the filter construction and makes it more stable and reliable.Type: GrantFiled: March 8, 2010Date of Patent: July 1, 2014Assignee: Her Majesty the Queen in Right of Canada, as Represented by the Minister of Industry, Through the Communications Research Centre CanadaInventors: Howard Rideout, Joe Seregelyi, Ping Lu, Stéphane Paquet, Jianping Yao, Stephen J. Mihailov, John Oldham, Mario Caron
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Patent number: 8727613Abstract: A dual parameter sensor for sensing temperature and mechanical or chemical or related information is disclosed. The sensor is formed of an optical waveguide suitable for use in-situ in a high temperature environment having a Bragg grating written into a core region thereof with short-pulsed electromagnetic radiation. By noting the thermal Black Body radiation level above 650° C., wavelength shifts due to temperature can be decoupled from wavelength shifts due to the other parameter being sensed. Advantageously the thermal radiation can be used as an optical source to probe the Bragg grating, considerably simplifying the interrogating apparatus, removing the need for an extrinsic optical source to probe the sensor.Type: GrantFiled: May 30, 2011Date of Patent: May 20, 2014Assignee: National Research Council of CanadaInventor: Stephen J. Mihailov
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Patent number: 8402789Abstract: A method of producing a thermally stable grating allows the grating to be placed in environments where temperatures reach 1000° C. These gratings may be concatenated so as to form a sensor array. The method requires a step of lowering the characteristic intensity threshold of a waveguide by at least 25%, followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures of at least 10 hours at a temperature of at least 1000° C. Pre-writing a Type I grating before writing a minimal damage Type II grating lowers the characteristic threshold of the waveguide so that a stable low damage type II grating can be written; alternatively providing a hydrogen or deuterium loaded waveguide before writing the grating lowers the characteristic threshold of the waveguide.Type: GrantFiled: August 23, 2012Date of Patent: March 26, 2013Assignee: Her Majesty the Queen in Right of Canada, as Represented by the Minister of Industry, Through the Communications Research Centre CanadaInventors: Christopher W. Smelser, Stephen J. Mihailov, Dan Grobnic, Ping Lu, Robert B. Walker, Gino Cuglietta, Huimin Ding, Xiaoli Dai
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Publication number: 20120324959Abstract: A method of producing a thermally stable grating allows the grating to be placed in environments where temperatures reach 1000° C. These gratings may be concatenated so as to form a sensor array. The method requires a step of lowering the characteristic intensity threshold of a waveguide by at least 25%, followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures of at least 10 hours at a temperature of at least 1000° C. Pre-writing a Type I grating before writing a minimal damage Type II grating lowers the characteristic threshold of the waveguide so that a stable low damage type II grating can be written; alternatively providing a hydrogen or deuterium loaded waveguide before writing the grating lowers the characteristic threshold of the waveguide.Type: ApplicationFiled: August 23, 2012Publication date: December 27, 2012Applicants: the Communications Research Centre CanadaInventors: Christopher W. Smelser, Stephen J. Mihailov, Dan Grobnic, Ping Lu, Robert B. Walker, Gino Cuglietta, Huimin Ding, Xiaoli Dai
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Patent number: 8272236Abstract: A method of producing a thermally stable grating allows the grating to be placed in environments where temperatures reach 1000° C. and where the grating is relatively stable and has very low loss from scatter. These gratings have spectral characteristics that allow them to be concatenated so as to form a sensor array. The method requires a step of lowering the characteristic intensity threshold of a waveguide by at least 25%, followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures of at least 10 hours at a temperature of at least 1000° C.Type: GrantFiled: June 18, 2009Date of Patent: September 25, 2012Assignee: Her Majesty the Queen in right of Canada, as represented by the Minister of Industry, through the Communications Research Centre CanadaInventors: Christopher W. Smelser, Stephen J. Mihailov, Dan Grobnic, Ping Lu, Robert B. Walker, Gino Cuglietta, Haimin Ding, Xiaoli Dai
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Publication number: 20110292965Abstract: A dual parameter sensor for sensing temperature and mechanical or chemical or related information is disclosed. The sensor is formed of an optical waveguide suitable for use in-situ in a high temperature environment having a Bragg grating written into a core region thereof with short-pulsed electromagnetic radiation. By noting the thermal Black Body radiation level above 650° C., wavelength shifts due to temperature can be decoupled from wavelength shifts due to the other parameter being sensed. Advantageously the thermal radiation can be used as an optical source to probe the Bragg grating, considerably simplifying the interrogating apparatus, removing the need for an extrinsic optical source to probe the sensor.Type: ApplicationFiled: May 30, 2011Publication date: December 1, 2011Inventor: Stephen J. Mihailov
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Publication number: 20100230621Abstract: A filter and a method of filtering a high frequency electrical signal using photonic components is disclosed. The filter has a serially fiber-coupled laser source, a modulator, a filter, and a photodetector. The electrical signal is applied to the modulator. The modulated light propagates through the filter which is constructed to pass not only a modulated sideband, but also at least a fraction of light at the carrier frequency of the laser. The photodetector detects a signal at the beat frequency between the carrier and sideband signals, after both signals have propagated through the filter. As a result, a separate optical branch for light at the carrier frequency is not required, which considerably simplifies the filter construction and makes it more stable and reliable.Type: ApplicationFiled: March 8, 2010Publication date: September 16, 2010Inventors: Howard RIDEOUT, Joe SEREGELYI, Ping LU, Stéphane PAQUET, Jianping YAO, Stephen J. MIHAILOV, John OLDHAM, Mario CARON
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Patent number: 7689087Abstract: A method of inducing birefringence in an optical waveguide is disclosed wherein the waveguide cladding is irradiated with energy of a sufficient intensity so as to induce a stress in the optical waveguide so as to cause a multitude of spaced stress induced regions within the cladding of the optical waveguide such that there are 10 to 5000 spaced regions per mm and wherein the stress induced regions are proximate the core greater than 2 microns distance from the core-cladding interface. This waveguide has numerous uses, for example a fiber sensor.Type: GrantFiled: July 9, 2008Date of Patent: March 30, 2010Assignee: Her Majesty the Queen in right of Canada, as represented by the Minister of Industry, Through the Communications Research Centre CanadaInventors: Stephen J. Mihailov, Dan Grobnic, Christopher W. Smelser, Robert B. Walker, Ping Lu, Xiaoli Dai, Huimin Ding, Gino Cuglietta
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Publication number: 20090317928Abstract: A method of producing a thermally stable grating allows the grating to be placed in environments where temperatures reach 1000° C. and where the grating is relatively stable and has very low loss from scatter. These gratings have spectral characteristics that allow them to be concatenated so as to form a sensor array. The method requires a step of lowering the characteristic intensity threshold of a waveguide by at least 25%, followed by irradiating the waveguide with femtosecond pulses of light having a sufficient intensity and for a sufficient duration to write the grating so that at least 60% of the grating remains after exposures of at least 10 hours at a temperature of at least 1000° C.Type: ApplicationFiled: June 18, 2009Publication date: December 24, 2009Inventors: Christopher W. Smelser, Stephen J. Mihailov, Dan Grobnic, Ping Lu, Robert B. Walker, Gino Cuglietta, Haimin Ding, Xiaoli Dai
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Patent number: 7567734Abstract: An optical sensor for sensing information relating to an analyte liquid or gas, has a a planar substrate having a refractive index nc. The planar substrate supports a ridge waveguide having an unclad top portion having a refractive index nr. The substrate serves as cladding layer for the ridge waveguide at a location where the ridge waveguide contacts the substrate. A Bragg grating inscribed in the ridge waveguide has two modes for providing information relating to both temperature and refractive index of the surrounding analyte liquid or gas. A cladding mode has a different response to the analyte when compared to a Bragg resonance response. Both modes have a same reaction to temperature, wherein said Bragg grating is formed within the unclad region of ridge waveguide, wherein nc.<nr. Advantageously multiple parameters can be sensed using only a single Bragg grating.Type: GrantFiled: August 8, 2008Date of Patent: July 28, 2009Assignee: Her Majesty the Queen in right of Canada, as represented by the Minister of Industry, through the Communications Research Centre CanadaInventors: Xiaoli Dai, Stephen J. Mihailov, Robert B. Walker, Chantal Blanchetiere, Claire Callender, Huimin Ding, Ping Lu, Dan Grobnic, Christopher W. Smelser, Gino Cuglietta
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Patent number: 7515792Abstract: A method of increasing the refractive index in a photosensitive glass is disclosed so as to induce an refractive index change of at least 10?5 within a region of the glass. The method includes the step of providing a hydrogen or deuterium loaded doped glass material wherein a dopant within the glass is photosensitive to infrared radiation in the presence of hydrogen or deuterium. The hydrogen or deuterium loaded doped glass is subsequently irradiated with femtosecond pulses of infrared light having an intensity of at least 109 W/cm2 and less than 5×1013 W/cm2.Type: GrantFiled: March 7, 2007Date of Patent: April 7, 2009Assignee: Her Majesty the Queen in Right of Canada as Represented by the Minister of Industry, Through the Communications Research Centre CanadaInventors: Stephen J. Mihailov, Christopher W. Smelser, Dan Grobnic, Robert B. Walker, Ping Lu, Huimin Ding, Gino Cuglietta, Xiaoli Dai
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Publication number: 20090041405Abstract: An optical sensor for sensing information relating to an analyte liquid or gas, has a a planar substrate having a refractive index nc. The planar substrate supports a ridge waveguide having an unclad top portion having a refractive index nr. The substrate serves as cladding layer for the ridge waveguide at a location where the ridge waveguide contacts the substrate. A Bragg grating inscribed in the ridge waveguide has two modes for providing information relating to both temperature and refractive index of the surrounding analyte liquid or gas. A cladding mode has a different response to the analyte when compared to a Bragg resonance response. Both modes have a same reaction to temperature, wherein said Bragg grating is formed within the unclad region of ridge waveguide, wherein nc<nr. Advantageously multiple parameters can be sensed using only a single Bragg grating.Type: ApplicationFiled: August 8, 2008Publication date: February 12, 2009Inventors: Xiaoli Dai, Stephen J. Mihailov, Robert B. Walker, Chantal Blanchetiere, Claire Callender, Huimin Ding, Ping Lu, Dan Grobnic, Christopher W. Smelser, Gino Cuglietta
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Patent number: 7483615Abstract: Fiber Bragg gratings were written in pure silica photonic crystal fibers and photonic crystal fiber tapers with 125 fs, 800 nm IR radiation. High reflectivites were achieved with short exposure times in the tapers. Both multimode and single mode grating reflections were achieved in the fiber tapers. By tapering the photonic crystal fibers scattering that would otherwise have occurred was lessened and light external to the fiber could reach the core effectively to write a grating.Type: GrantFiled: February 26, 2007Date of Patent: January 27, 2009Assignee: Her Majesty the Queen in Right of Canada as represented by the Minister of Industry, through the Communications Research Centre CanadaInventors: Stephen J. Mihailov, Dan Grobnic, Huimin Ding, Robert B. Walker, Christopher W. Smelser, Ping Lu, Xiaoli Dai, Gino Cuglietta
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Publication number: 20080310789Abstract: A method of inducing birefringence in an optical waveguide is disclosed wherein the waveguide cladding is irradiated with energy of a sufficient intensity so as to induce a stress in the optical waveguide so as to cause a multitude of spaced stress induced regions within the cladding of the optical waveguide such that there are 10 to 5000 spaced regions per mm and wherein the stress induced regions are proximate the core greater than 2 microns distance from the core-cladding interface. This waveguide has numerous uses, for example a fiber sensor.Type: ApplicationFiled: July 9, 2008Publication date: December 18, 2008Inventors: Stephen J. Mihailov, Dan Grobnic, Christopher W. Smelser, Robert B. Walker, Ping Lu, Xiaoli Dai, Huimin Ding, Gino Cuglietta
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Patent number: 7379643Abstract: A retro-reflective sensor for sensing mechanical, chemical or temperature related information, is disclosed. The sensor is formed of an optical waveguide suitable for use in-situ in a high temperature environment having a Bragg grating written into a core region thereof with short-pulsed electromagnetic radiation, said optical waveguide having a glass transition temperature substantially higher than that of silica. Preferably the sensor is written into a length of sapphire fiber or within a zirconium waveguide. Preferably the pulse duration of the short pulsed electromagnetic radiation is less than 500 picoseconds.Type: GrantFiled: October 5, 2005Date of Patent: May 27, 2008Assignee: Her Majesty the Queen in Right of Canada as represented by the Minister of Industry, through the Communications Research Centre CanadaInventors: Stephen J. Mihailov, Dan Grobnic, Christopher Smelser, Robert Walker, Ping Lu, Huimin Ding, George Henderson, Xiaoli Dai
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Publication number: 20070201802Abstract: Fiber Bragg gratings were written in pure silica photonic crystal fibers and photonic crystal fiber tapers with 125 fs, 800 nm IR radiation. High reflectivites were achieved with short exposure times in the tapers. Both multimode and single mode grating reflections were achieved in the fiber tapers. By tapering the photonic crystal fibers scattering that would otherwise have occurred was lessened and light external to the fiber could reach the core effectively to write a grating.Type: ApplicationFiled: February 26, 2007Publication date: August 30, 2007Inventors: Stephen J. Mihailov, Dan Grobnic, Huimin Ding, Robert B. Walker, Christopher W. Smelser, Ping Lu, Xiaoli Dai, Gino Cuglietta
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Patent number: 7245795Abstract: The invention relates to an optical waveguide device for monitoring a characteristics of light, e.g. a wavelength. The device incorporates a waveguide, such as an optical fiber, with an embedded tilted Bragg grating operating in a regime of wavelength detuning. The grating is designed to disperse light azimuthally in two or more different directions about the fiber axis, said directions changing with wavelength. A photodetector array is provided for detecting the azimuthal distribution of light. A processor coupled to the photodetector array determines wavelength information from the detected azimuthal distribution of the out-coupled light.Type: GrantFiled: November 15, 2005Date of Patent: July 17, 2007Assignee: Her Majesty the Queen in Right of Canada as represented by the Minister of Industry, through the Communications Research Centre CanadaInventors: Robert Walker, Stephen J. Mihailov, Ping Lu, Dan Grobnic, Xiaoli Dai, Huimin Ding, George Henderson, Christopher Smelser
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Patent number: 7031571Abstract: A novel Bragg grating filter in optical waveguiding fiber with suppressed cladding mode coupling and method of producing same is disclosed. The novel grating structure is induced in both the core and the cladding of the optical fiber irrespective of the photosensitivity of the core or cladding to actinic radiation. Such core and cladding of the optical fiber need not be chemically doped to support the grating. The method incorporates an ultra short duration pulse laser source. Electromagnetic radiation provided from the laser propagates to a diffractive element positioned a specific distance to the target material such that the diffracted electromagnetic radiation forms a 2-beam interference pattern, the peaks of which are sufficiently intense to cause a change in index of refraction.Type: GrantFiled: March 19, 2004Date of Patent: April 18, 2006Assignee: Her Majesty the Queen in right of Canada, as represented by the Minister of Industry through the Communications Research Centre CanadaInventors: Stephen J. Mihailov, Dan Grobnic, Christopher Smelser, Robert Walker, Ping Lu, Huimin Ding, George Henderson, Xiaoli Dai