Patents by Inventor Julian D. C. Jones

Julian D. C. Jones 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).

  • Patent number: 6137573
    Abstract: A sensor system (10) incorporating an interferometer operates as an optical strain gauge. The system (10) is arranged to generate interferograms characterised by an optical path difference between light traversing a sensor arm (12) of the interferometer and light traversing a reference arm (58). Each arm incorporates a highly birefringent optical fibre (38, 58) capable of supporting light propagation at two velocities in two different polarisation modes. A first interferogram is generated between light coupled into the fast eigenmodes of each fibre and a second is generated between light coupled into the slow eigenmodes. Mean optical group delay (.tau..sub.MGD) and differential optical group delay (.tau..sub.DGD) of these interferograms are affected differently by temperature and strain and thus provide a means of discriminating between these attributes of the sensor environment. Thus simultaneous measurement of strain and temperature is achieved.
    Type: Grant
    Filed: September 16, 1998
    Date of Patent: October 24, 2000
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventors: David G Luke, Roy McBride, Peter A Lloyd, James G Burnett, Alan H Greenaway, Julian D C Jones
  • Patent number: 5850068
    Abstract: When a laser beam interacts with a workpiece to be welded by the beam, a plume of optical radiation is generated. An apparatus and method is disclosed in which radiation from the plume is received back through a beam delivery path comprising optical elements (L1,L2) having chromatic aberration. This alters the focus of different spectral bands of the plume radiation and a discriminating aperture is formed by a face of an optical fibre (3). After passing through the fibre, the plume radiation is separated from any laser radiation and the respective powers of the different spectral bands are measured (5). By subtraction, an error signal is obtained which is used to control the focus of the laser beam.
    Type: Grant
    Filed: June 3, 1997
    Date of Patent: December 15, 1998
    Assignee: Lumonics Ltd.
    Inventors: Christopher Nicholas David Peters, Julian D C Jones, Duncan Paul Hand, Francis Martin Haran
  • Patent number: 5803607
    Abstract: Apparatus for the measurement of unsteady gas temperatures comprises (a) a temperature probe having a sensing element. The sensing element has an optical interferometer optically coupled to one end of a first, addressing optical fibre. The interferometer has a first partially reflective surface defined at the end of the addressing fibre and a second partially reflective surface spaced from the first partially reflective surface by an optical path length I.
    Type: Grant
    Filed: January 6, 1997
    Date of Patent: September 8, 1998
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britian and Northern Ireland
    Inventors: Julian D C Jones, James S Barton, Stephen R Kidd, Kamaljit S Chana
  • Patent number: 5721615
    Abstract: A sensor system in an interferometric arrangement has a sensor arm and a reference arm. The reference arm is in a stable environment and the sensor arm is arranged to be subject to variations in strain and/or temperature. Radiation from a broadband source propagates through the arrangement and a broadband interferogram is generated as an air gap is scanned. The interferogram is recorded on an oscilloscope and analyzed using signal processing software on a computer. From the analysis the changes in group delay and optical dispersion of the light in the sensor arm due to strain and temperature changes is measured, and values for the strain and/or temperature changes calculated. A narrowband light source may be used for accurate calibration of path length differences during scanning. The strain and temperature on the sensor arm may be calibrated or tested using clamps and a thermal enclosure.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: February 24, 1998
    Assignee: The Secretary of State for Defense in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventors: Roy McBride, James G. Burnett, Alan Howard Greenaway, Julian D. C. Jones
  • Patent number: 5351116
    Abstract: A differential laser Doppler velocimeter is based on the use of a modified fibre optic Sagnac Interferometer 1,2. The interferometer phase is dependent not on the target displacement, but on its velocity. The output intensity of the interferometer may be modulated by control means PC which controls loop birefringence introducing a phase bias and polarization offset between counter-propagating beams.
    Type: Grant
    Filed: January 6, 1993
    Date of Patent: September 27, 1994
    Inventors: James S. Barton, William K. D. Borthwick, David Harvey, Julian D. C. Jones, Roy McBride
  • Patent number: 5319195
    Abstract: A laser system comprises a laser (500) whose output beam is delivered to a workpiece (504) by an optical fiber (502). A transducer (506) detects the power of light propagating in the cladding layer of fiber (502) at a position near its input end. The transducer (506) also strips out the light travelling in the cladding layer. The output of transducer (506) is divided by the output of a transducer (507), which detects the power of the output beam of laser (500), to produce a signal indicative of misalignment between the laser beam and the core of fiber (502) at the input face. A transducer (505) comprises a second fiber (508) optically coupled with the cladding layer of fiber (502). Light emitted from the ends of fiber (508) is detected by a pair of detectors (509, 510), whose outputs are indicated on displays (512, 514). Display (512) provides information on the integrity of transmissions of the laser beam through fiber (502).
    Type: Grant
    Filed: March 24, 1992
    Date of Patent: June 7, 1994
    Assignee: Lumonics Ltd.
    Inventors: Julian D. C. Jones, Daoning Su, Alvaro A. P. Boechat, Clive L. M. Ireland
  • Patent number: 4725143
    Abstract: An interferometric sensor includes an optical fiber polarimetric sensing element (5) for detecting a required measurand and is configured so as to derive interference output signals, which are simultaneously monitored by photodetectors (9, 11), from both conventional, for example, Michelson, and polarimetric interferometer arrangements. The sensor therefore offers the high resolution of a conventional interferometer in conjunction with the increased dynamic range of a polarimetric device.
    Type: Grant
    Filed: February 27, 1986
    Date of Patent: February 16, 1988
    Assignee: Kent Scientific and Industrial Projects Limited
    Inventors: Julian D. C. Jones, David A. Jackson, Michael Corke
  • Patent number: 4706502
    Abstract: A flowmeter for measuring the velocity of fluid flow by monitoring the vortex shedding frequency of the fluid flow comprises a single mode optical fibre sensing element (1) for detecting vortex shedding and utilizes interferometric techniques for producing an electrical output signal corresponding to the vortex shedding frequency. The sensing element (1) comprises at least part of the signal arm (2) of an interferometer (3) which also includes means (12) for deriving a reference signal from the illuminating light source (4). The flow induced oscillation of the sensing element (1) caused by vortex shedding produces modulations of the interferometer output which is monitored by a photodetector (14) which, in turn, produces a modulated electrical output signal which can be processed by a signal processing system (16-19) to identify the vortex shedding frequency and, hence, produce a measurement of the flow velocity.
    Type: Grant
    Filed: February 27, 1986
    Date of Patent: November 17, 1987
    Assignee: Kent Scientific and Industrial Projects Limited
    Inventors: Julian D. C. Jones, David A. Jackson, Pedram A. Leilabady
  • Patent number: 4678909
    Abstract: Optical pressure sensing apparatus comprises an optical fibre interferometer arranged to sense the movement of a pressure responsive element and produce an interference signal at its output which can be monitored and processed to measure changes in the pressure applied to the pressure responsive element. The interferometer comprises a signal arm coupled to the pressure responsive element and a fixed reference arm. A light source supplies light to the input of the interferometer via an optical fibre and monitoring and processing electronics connected to the output determine the optical phase shift between the light beams propagated in the signal and reference arms and produce a pressure reading.
    Type: Grant
    Filed: November 25, 1985
    Date of Patent: July 7, 1987
    Assignee: Kent Scientific and Industrial Projects Limited
    Inventors: David A. Jackson, Michael Corke, Alan D. Kersey, Julian D. C. Jones