Abstract: A temperature sensor and temperature sensing system for sensing changes in temperature up to a predetermined temperature is disclosed. The temperature sensor includes a microstructured optical fiber where the microstructured optical fiber includes a plurality of longitudinal channels extending along the microstructured optical fiber. The sensor also includes a fiber Bragg grating formed in the microstructured optical, fiber by generating a periodic modulation in the refractive index along a core region of the microstructured optical fiber. The fiber Bragg grating is operable to produce band reflection at a reflection wavelength that varies in accordance with changes in temperature at the core region of the optical fiber.

Abstract: A die and method for extruding an extrudable material to form an extruded member is described. In one embodiment, the die comprises a barrier member comprising a plurality of feed channels that extend through the barrier member. Furthermore, the die incorporates a passage forming member extending from the barrier member substantially in the direction of extrusion. The feed channels are arranged with respect to the passage forming member to allow the extrudable material to substantially flow about the passage forming member to form a corresponding passage in the extruded member.

Abstract: A temperature sensor and temperature sensing system for sensing changes m temperature up to a predetermined temperature is disclosed. The temperature sensor includes a microstructured optical fiber where the micro-structured optical fiber includes a plurality of longitudinal channels extending along the microstructured optical fiber. The sensor also includes a fiber Bragg grating formed in the microstructured optical, fiber by generating a periodic modulation in the refractive index along a core region of the microstructured optical fiber. The fiber Bragg grating is operable to produce band reflection at a reflection wavelength that varies in accordance with changes in temperature at the core region of the optical fiber.

Abstract: A die and method for extruding an extrudable material to form an extruded member is described. In one embodiment, the die comprises a barrier member comprising a plurality of feed channels that extend through the barrier member. Furthermore, the die incorporates a passage forming member extending from the barrier member substantially in the direction of extrusion. The feed channels are arranged with respect to the passage forming member to allow the extrudable material to substantially flow about the passage forming member to form a corresponding passage in the extruded member.

Abstract: A sensor based on optical fiber technology is described. The sensor includes an elongate core for propagating light having an excitation wavelength; an interaction region that includes a fluorescent material for excitation by the propagated light to produce fluorescent light; and an interface region defining a boundary between the elongate core and the interaction region. The elongate core of the sensor is adapted to increase an intensity of the propagated light at the interface region to increase the amount of captured fluorescent light in the elongate core.

Abstract: A method of forming a nanowire is disclosed. In one embodiment, a primary preform is formed comprising at least one central region and a support structure. The primary preform is then drawn to a cane, which is then inserted into an outer portion, to form a secondary preform. The secondary preform is then drawn until the at least one central portion is a nanowire. The method can produce nanowires of far greater length than existing methods, and can reduce the likelihood of damaging the nanowire when handling.

Abstract: A method of forming a nanowire is disclosed. In one embodiment, a primary preform is formed comprising at least one central region and a support structure. The primary preform is then drawn to a cane, which is then inserted into an outer portion, to form a secondary preform. The secondary preform is then drawn until the at least one central portion is a nanowire. The method can produce nanowires of far greater length than existing methods, and can reduce the likelihood of damaging the nanowire when handling.

Abstract: A sensor based on optical fiber technology is described. The sensor includes an elongate core for propagating light having an excitation wavelength; an interaction region that includes a fluorescent material for excitation by the propagated light to produce fluorescent light; and an interface region defining a boundary between the elongate core and the interaction region. The elongate core of the sensor is adapted to increase an intensity of the propagated light at the interface region to increase the amount of captured fluorescent light in the elongate core.

Abstract: A die and method for extruding an extrudable material to form an extruded member is described. In one embodiment, the die comprises a barrier member comprising a plurality of feed channels that extend through the barrier member. Furthermore, the die incorporates a passage forming member extending from the barrier member substantially in the direction of extrusion. The feed channels are arranged with respect to the passage forming member to allow the extrudable material to substantially flow about the passage forming member to form a corresponding passage in the extruded member.

Abstract: A method of forming a nanowire is disclosed. In one embodiment, a primary preform is formed comprising at least one central region and a support structure. The primary preform is then drawn to a cane, which is then inserted into an outer portion, to form a secondary preform. The secondary preform is then drawn until the at least one central portion is a nanowire. The method can produce nanowires of far greater length than existing methods, and can reduce the likelihood of damaging the nanowire when handling.

Abstract: Microstructured optical fibre is fabricated using extrusion. The main design of optical fibre has a core suspended in an outer wall by a plurality of struts. A specially designed extruder die is used which comprises a central feed channel, flow diversion channels arranged to divert material radially outwards into a welding chamber formed within the die, a core forming conduit arranged to receive material by direct onward passage from the central feed channel, and a nozzle having an outer part in flow communication with the welding chamber and an inner part in flow communication with the core forming conduit, to respectively define an outer wall and core of the preform. With this design a relatively thick outer wall can be combined with thin struts (to ensure extinction of the optical mode field) and a core of any desired diameter or other thickness dimension in the case of non-circular cores. As well as glass, the extrusion process is suitable for use with polymers.

Abstract: An optical fiber structure having a holey fiber arranged in a holey outer support structure made up of holey tubes encased in a thin walled outer jacket. The holey fiber may have a solid core surrounded by a holey cladding having a plurality of rings of holes. With the invention it is possible to produce robust, coated and jacketed fibers with microstructured core features of micrometer size relatively easily using existing fiber fabrication technology. This improvement is a result of the outer holey structure which reduces the thermal mass of the supporting structure and makes it possible to reliably and controllably retain small hole features during the fiber fabrication process.

Abstract: An optical fibre device based on the Raman effect comprises a first optical source to provide light at a first wavelength, and a holey optical fibre which receives the light from the first optical source such that optical gain or loss is provided at a second wavelength by the effect of Raman scattering within the fibre. For optical gain, the second wavelength is longer than the first wavelength, and the device can be operated as an amplifier, or as a laser if optical feedback is provided. For optical loss, the second wavelength is shorter than the first, and the device may be used as an optical modulator. The fibre may be fabricated from pure silica, although other undoped or doped materials may alternatively be used to tailor properties of the fibre such as gain spectrum, bandwidth, power handling capability and mode propagation.

Abstract: A source of optical pulses, comprises an optical source operable to generate ultrashort optical pulses at a first wavelength; and an optical fiber amplifier comprising an optical fiber having a core containing a dopant to provide optical gain at the first wavelength and anomalous dispersion over a wavelength range including the first wavelength and a second wavelength. The optical fiber receives the ultrashort optical pulses, amplifies the ultrashort optical pulses, and alters the wavelength of the ultrashort optical pulses to at least the second wavelength by the soliton-self-frequency shifting effect. Microstructured and/or tapered fibers can be used to provide the required dispersion characteristics. Pulses can be generated in one of three spectral regimes—monocolor solitons, multicolor solitons and continuous broadband spectra by adjusting the energy of the optical pulses, and tunability can be achieved by varying the power of pump light provided to the amplifier.

Abstract: An optical parametric device for broadband parametric processes involving first and second frequencies &ohgr;1 and &ohgr;2. The device comprises an optical fiber comprising a core and a cladding, the cladding being microstructured with holes for providing waveguiding confinement of at least one optical mode in the core. The optical fiber is poled lengthwise with a non-linearity profile having a period that satisfies a quasi phase matching (QPM) condition including the first and second frequencies. Through the use of a poled holey fiber of suitable hole structure, it is possible to increase the second harmonic (SH) efficiency in comparison with poled conventional (non-holey) fiber. This is achieved by a combination of a low mode overlap area between the fundamental and SH waves, a low absolute value of the mode area, and a large SH bandwidth per unit length of the fiber, all of which can be provided together in a poled holey fiber.

Abstract: An optical fiber structure having a holey fiber arranged in a holey outer support structure made up of holey tubes encased in a thin walled outer jacket. The holey fiber may have a solid core surrounded by a holey cladding having a plurality of rings of holes. With the invention it is possible to produce robust, coated and jacketed fibers with microstructured core features of micrometer size relatively easily using existing fiber fabrication technology. This improvement is a result of the outer holey structure which reduces the thermal mass of the supporting structure and makes it possible to reliably and controllably retain small hole features during the fiber fabrication process.

Abstract: A source of optical pulses, comprises an optical source operable to generate ultrashort optical pulses at a first wavelength; and an optical fiber amplifier comprising an optical fiber having a core containing a dopant to provide optical gain at the first wavelength, and anomalous dispersion over a wavelength range including the first wavelength and a second wavelength. The optical fiber receives the ultrashort optical pulses, amplifies the ultrashort optical pulses, and alters the wavelength of the ultrashort optical pulses to at least the second wavelength by the soliton-self-frequency shifting effect. Microstructured and/or tapered fibers can be used to provide the required dispersion characteristics. Pulses can be generated in one of three spectral regimes-monocolor solitons, multicolor solitons and continuous broadband spectra by adjusting the energy of the optical pulses, and tunability can be achieved by varying the power of pump light provided to the amplifier.

Abstract: An optical parametric device for broadband parametric processes involving first and second frequencies &ohgr;1 and &ohgr;2. The device comprises an optical fiber comprising a core and a cladding, the cladding being microstructured with holes for providing waveguiding confinement of at least one optical mode in the core. The optical fiber is poled lengthwise with a non-linearity profile having a period that satisfies a quasi phase matching (QPM) condition including the first and second frequencies. Through the use of a poled holey fiber of suitable hole structure, it is possible to increase the second harmonic (SH) efficiency in comparison with poled conventional (non-holey) fiber. This is achieved by a combination of a low mode overlap area between the fundamental and SH waves, a low absolute value of the mode area, and a large SH bandwidth per unit length of the fiber, all of which can be provided together in a poled holey fiber.