The University of Sydney

The University of Melbourne

The University of Syndey

John Canning

Mattias Lennart Aslund

Mark Geoffrey Sceats

Graham Town

Danny Wong

Dmitrii Yurievich Stepanov

Paul Blazkiewicz

Wei Xu

Leon Poladian

Steven Manos

Maryanne Candida Jane Large

Tom Ryan

Kristy Lee Sommer

Martin Alexander Van Eijkolonborg

Katja Lyytikainon

Alexander Argyros

Shane Huntington

Joseph Zagari

An optical fiber being optically transmissive at a predetermined wavelength of light &#x3bb; and comprising a plurality of coaxial layers. Each layer having an optical path length that varies radially, the coaxial layers being arranged to give the fiber a refractive index profile which, in use, causes sufficient Fresnel diffraction of the light such that it is guided in the fiber. The refractive index of a cladding region () is intermittently suppressed by controlling heating of the preform tube, thus forming a chirped saw-tooth profile (). The optical fiber may include a lens. In this case, each of the layers has an optical path length that increases gradually outwardly by substantially n&#xd7;&#x3bb;/2 (n: integer).

Optical fiber with fresnel diffraction

The invention relates to a method of producing a preform for a holey optical fiber, and more particularly, to a method of producing polymer holey optical fiber using novel capillary and cane designs that allow a construction of complex holey structures. The capillaries may have a complex internal structure including multiple holes, holes of non-circular shape, off-center holes, holes of different sizes, or any combination of these. The canes may have a complex external shape to define interstitial holes when the canes arc combined in a stack (see). The capillaries and canes may be made of different materials and combined within the same structure.

Constructing preforms from capillaries and canes

A method of thermally poling a silica based waveguide ( ) comprises exposing a region of the waveguide ( ) to an electric field (for example, via capillary electrodes ( ) inserted into holes in the waveguide); directing a laser beam ( ) into the region exposed to the electric field to effect localized heating of the region via direct absorption; and scanning the laser beam ( ) over the region at a rate selected to avoid heating of the region above the glass transition temperature. Reversing the electric field while scanning the laser beam ( ) allows the formation of periodic poled gratings. The waveguide ( ) can comprise an optical fiber.

Laser assisted thermal poling of silica based waveguides

An optical waveguide ( ) has a grating structure ( ) in which gratings of different orders are superimposed. When first and second order gratings are superimposed, input light is partially reflected by the first order component and partially coupled out of the waveguide by the second order component. The second order component can also be used to couple external light into the waveguide ( ). The grating structure ( ) has applications to free space couplers, optical sensors, and suppression of ripples in dispersion compensators.

Grating structure and optical devices

A method of creating an optical structure within a photosensitive light transmissive material comprising the steps of: (a) exposing a selected region of the material to radiation at a wavelength selected to effect a refractive index change in the material; (b) terminating the exposure to the radiation at a selected fluence; and afterwards (c) exposing at least one portion of the selected region to UV radiation at a level sufficient to vary the refractive index of the material within the selected region to form the optical structure; wherein the fluence is selected such that the optical structure is substantially thermally stable without a requirement for post-processing annealing.

Method for creating an optical structure within a photosensitive light transmissive material and of enhancing the photosensitivity of the photosensitive light transmissive material

A method of modifying birefringence properties of a waveguide formed within a carrier, the method comprising the steps of inducing a stress anisotropy in the waveguide and effecting a differential decrease in a first refractive index of one mode in the waveguide with respect to a second refractive index of another mode of the waveguide.

Process for control of birefringence in waveguides

A waveguide having photosensitive properties is disclosed comprising: a waveguide substrate; a first cladding layer formed on the waveguide substrate; a UV absorbing layer formed on the first cladding layer; a UV sensitive layer having optical transmission properties adapted to be changed with UV irradiation, the layer formed on or closely adjacent the UV absorbing layer; and a second cladding layer, being substantially UV transparent, on the UV sensitive layer. Preferably, there is further provided a third cladding layer intermediate of the UV absorbing layer and the UV sensitive layer. The UV absorbing layer comprises a germanosilicate material. The absorbing layer can be adapted to change a physical property upon UV absorption. The UV absorbing layer can be variable thickness, the thickness being in accordance with predetermined requirements.

Absorbing layer for minimizing substrate exposure during the UV writing of a waveguide grating in addition to a birefringent control system

A method of creating an optical filter for selectively filtering an optical signal transmitted through the filter, the method comprising: constructing a Bragg grating in an optical element coupled to an optical path way for the transmission of the optical signal to suppress background radiation; and adjusting the coupling so as to produce a selective transmission spectrum in according with predetermined requirements.

Narrow transmission bandpass filters utilizing bragg grating assisted mode conversion

A single longitudinal mode narrow linewidth and low threshold all fiber laser arrangement is disclosed, constructed from a ring cavity, a gain portion in the ring cavity, an input-output coupling interposed within the cavity and pumping means connected to the ring cavity and to the grating such that, upon actuation of the pumping means, the arrangement acts as a laser.

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Carlton, Australia

John Canning