Patents by Inventor Susan P. Craig

Susan P. Craig 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).

  • Wave-guiding structure with lasing properties
    Patent number: 5412672
    Abstract: Optical wave-guides, e.g. fibres, for use as photonic amplifiers have a path region partly or, preferably, wholly composed as a silica/germania glass with 0.1 to 5000 ppm mole of Er.sup.3+ as a lasing additive and alumina to adjust the bandwidth, the Ge:Al mole ratio being more than 2.8, e.g. 1:0.001 to 0.25. It is surprising that low amounts of alumina have a useful and significant effect on the lasing bandwidth whereby frequency division multiplex is facilitated.
    Type: Grant
    Filed: December 10, 1993
    Date of Patent: May 2, 1995
    Assignee: British Telecommunications public limited company
    Inventors: Benjamin J. Ainslie, Susan P. Craig-Ryan
  • Wave-guiding structure with lasing properties
    Patent number: 5278850
    Abstract: Optical wave-guides, e.g. fibres, for use as photonic amplifiers have a path region partly or, preferably, wholly composed as a silica/germania glass with 0.1 to 5000 ppm mole of Er.sup.3+ as a lasing additive and alumina to adjust the bandwidth, the Ge:Al mole ratio being more than 2.8, e.g. 1:0.001 to 0.25. It is surprising that low amounts of alumina have a useful and significant effect on the lasing bandwidth whereby frequency division multiplex is facilitated.
    Type: Grant
    Filed: December 16, 1992
    Date of Patent: January 11, 1994
    Assignee: British Telecommunications
    Inventors: Benjamin J. Ainslie, Susan P. Craig-Ryan
  • Optical fibre with fluorescent additive
    Patent number: 4923279
    Abstract: An optical fibre for use in fibre lasers has the lasing additive eg Er.sup.3+, concentrated in center of the core. Preferably the core has an inner region which contains the additive and an outer region which is dopant free. The concentration of the dopant reduces the pump threshold for a laser and improves the gain performance for a given pump power. The fibre is conveniently made in MCVD. The use of Al.sub.2 O.sub.3 in the inner zone appears to reduce loss of dopant during tube collapse.
    Type: Grant
    Filed: October 13, 1988
    Date of Patent: May 8, 1990
    Assignee: British Telecommunications plc
    Inventors: Benjamin J. Ainslie, Susan P. Craig, Jonathan R. Armitage
  • Preparation of glass fibre
    Patent number: 4799946
    Abstract: Rare earth elements, e.g. Nd, are introduced into optical glass fibre for telecommunications by evaporating a suitable salt, e.g. NdCl.sub.3, from a glass sponge into the gas stream used to deposit core material. Preferred sponges are in the form of tubes having an outer impervious layer and an inner porous layer. These sponges are conveniently made by MCVD and the impregnation is preferably carried out using an alcoholic solution of the impregnant.
    Type: Grant
    Filed: March 20, 1987
    Date of Patent: January 24, 1989
    Assignee: British Telecommunications plc
    Inventors: Benjamin J. Ainslie, Susan P. Craig
  • Optical fibre amplifier with fluorescent additive and method of amplifying signals using same
    Patent number: RE35946
    Abstract: An optical fibre for use in fibre lasers has the lasing additive eg Er.sup.3+, concentrated in center of the core. Preferably the core has an inner region which contains the additive and an outer region which is dopant free. The concentration of the dopant reduces the pump threshold for a laser and improves the gain performance for a given pump power. The fibre is conveniently made in MCVD. The use of Al.sub.2 O.sub.3 in the inner zone appears to reduce loss of dopant during tube collapse.
    Type: Grant
    Filed: May 6, 1992
    Date of Patent: November 3, 1998
    Assignee: British Telecommunications plc
    Inventors: Benjamin J. Ainslie, Susan P. Craig, Jonathan R. Armitage