Abstract: A new class of phase change materials has been discovered based on compounds of: Ga; lanthanide; and chalcogenide. This includes compounds of Ga, La, and S (GLS) as well as related compounds in which there is substitution of S with O, Se and/or Te. Moreover, La can be substituted with other lanthanide series elements. It has been demonstrated that this class of materials exhibit low energy switching. For example, the GLS material can provide an optical recording medium with erasability 3-5 dB greater than the erasability of GeSbTe (GST) material which is the standard material for phase change memories.

Abstract: A new class of phase change materials has been discovered based on compounds of: Ga; lanthanide; and chalcogenide. This includes compounds of Ga, La, and S (GLS) as well as related compounds in which there is substitution of S with O, Se and/or Te. Moreover, La can be substituted with other lanthanide series elements. It has been demonstrated that this class of materials exhibit low energy switching. For example, the GLS material can provide an optical recording medium with erasability 3-5 dB greater than the erasability of GeSbTe (GST) material which is the standard material for phase change memories.

Abstract: A new class of phase change materials has been discovered based on compounds of: Ga; lanthanide; and chalcogenide. This includes compounds of Ga, La, and S (GLS) as well as related compounds in which there is substitution of S with O, Se and/or Te. Moreover, La can be substituted with other lanthanide series elements. It has been demonstrated that this class of materials exhibit low energy switching. For example, the GLS material can provide an optical recording medium with erasability 3-5 dB greater than the erasability of GeSbTe (GST) material which is the standard material for phase change memories.

Abstract: To overcome problems of fabricating conventional core-clad optical fibre from non-silica based (compound) glass, it is proposed to fabricate non-silica based (compound) glass optical fibre as holey fibre i.e. one contining Longitudinal holes in the cladding. This removes the conventional problems associated with mismatch of the physical properties of the core and clad compound glasses, since a holey fibre can be made of a single glass composition. With a holey fibre, it is not necessary to have different glasses for the core and cladding, since the necessary refractive index modulation between core and cladding is provided by the microstructure of the clad, i.e. its holes, rather than by a difference in materials properties between the clad and core glasses. Specifically, the conventional thermal mismatch problems between core and clad are circumvented.

Abstract: An optical waveguide includes a clad of clad glass and a core of core glass. The clad glass includes gallium, lanthanum, and sulfur. The clad glass may include gallium sulfide and lanthanum oxide. The clad glass may also include lanthanum fluoride. The core glass includes gallium, lanthanum, sulfur, oxygen, and fluorine. The core glass may include gallium sulfide, lanthanum oxide, and lanthanum fluoride. An optical fiber perform is also disclosed.

Abstract: A new and improved hybrid of Ga:La:S (GLS) glass is provided, namely a glass comprising gallium sulfide, lanthanum oxide, and at least 2 mol % lanthanum fluoride. The Ga:La:S:O:F (GLSOF) glass retains the important properties of the Ga:La:S system, while introducing improved thermal stability and spectroscopic properties. In addition, GLSOF glasses are non-toxic. The glass formation region for GLSOF has been carefully evaluated with compositional variations. It has been identified that an area of glass formation as indicated by circles, is a new and previously undiscovered glass formation region.

Abstract: To overcome problems of fabricating conventional core-clad optical fibre from non-silica based (compound) glass, it is proposed to fabricate non-silica based (compound) glass optical fibre as holey fibre i.e. one contining Longitudinal holes in the cladding. This removes the conventional problems associated with mismatch of the physical properties of the core and clad compound glasses, since a holey fibre can be made of a single glass composition. With a holey fibre, it is not necessary to have different glasses for the core and cladding, since the necessary refractive index modulation between core and cladding is provided by the microstructure of the clad, i.e. its holes, rather than by a difference in materials properties between the clad and core glasses. Specifically, the conventional thermal mismatch problems between core and clad are circumvented.

Abstract: A new and improved hybrid of Ga:La:S (GLS) glass is provided, namely a glass comprising gallium sulfide, lanthanum oxide, and at least 2 mol % lanthanum fluoride. The Ga:La:S:O:F (GLSOF) glass retains the important properties of the Ga:La:S system, while introducing improved thermal stability and spectroscopic properties. In addition, GLSOF glasses are non-toxic. The glass formation region for GLSOF has been carefully evaluated with compositional variations. It has been identified that an area of glass formation as indicated by circles, is a new and previously undiscovered glass formation region.

Abstract: An optical fibre amplifier, laser or superluminescent source, consisting of a chalcogenide glass matrix hosting trivalent rare earth ions and which is doped with oxide in the form of a metallic oxide. The device utilizes the properties of the added oxide to improve the fabrication and efficiency of optical waveguide sources, in particular for applications around 1.3 &mgr;m. Specifically, the oxide broadens the wavelength range for pump absorption, broadens the wavelength range for light emission, increases the device efficiency through a change in lifetime of certain laser levels and modifies properties of the glass to prevent crystallization during fiber fabrication. The device exploits the intentional addition of oxide to improve amplifier, laser, glass and fiber properties.

Abstract: The core of a low phonon energy glass optical fibre is doped with trivalent Dysprosium ions for application as an efficient optical fibre amplifier operating around 1.3 .mu.m. The device utilises the transition .sup.6 H.sub.9/2 -.sup.6 F.sub.11/2 to .sup.6 H.sub.15/2. The low phonon energy (high quantum efficiency) glasses include mixed halides, chalcogenides and chalcohalides. Improvements in efficiency can be achieved by co-doping of the fibre core with Eu.sup.3+ and/or Tb.sup.3+ ions.