Gallium sulfide glasses

A transparent glass exhibiting excellent transmission far into the infrared region of the electromagnetic radiation spectrum consisting essentially, expressed in terms of mole percent, of 5-30% Ga.sub.2 S.sub.3, 0-10% R.sub.2 S.sub.3, wherein R is at least one network forming cation selected from the group consisting of aluminum, antimony, and indium, 55-94.5% GeS.sub.2, 0.5-25% MS.sub.x, wherein M is at least one modifying metal cation selected from the group consisting of barium, cadmium, calcium, lead, lithium, mercury, potassium, sodium, strontium, thallium, tin, yttrium, and a rare earth metal of the lanthanide series, 0-10% total selenide, 0-25% total chloride and/or fluoride, and wherein the sulfur and/or selenium content can vary between 85-125% of the stoichiometric value.

In a waveguide structure comprising a core glass demonstrating a high refractive index surrounded by a cladding glass demonstrating a lower refractive index, the improvement comprising a core glass consisting of a lanthanum gallium sulfide glass and a cladding glass consisting of a lanthanum gallium sulfide glass wherein calcium has replaced a sufficient proportion of the lanthanum to lower the refractive index thereof to impart a sufficient difference between the refractive index of said core glass and said cladding glass to achieve an appropriate numerical aperture in said waveguide structure.

In a waveguide structure comprising a core glass demonstrating a high refractive index surrounded by a cladding glass demonstrating a lower refractive index, the improvement comprising a cladding glass consisting of a lanthanum gallium sulfide glass and a core glass consisting of a lanthanum gallium sulfide glass wherein gadolinium has replaced a sufficient proportion of the lanthanum to raise the refractive index thereof to impart a sufficient difference between the refractive index of said core glass and said cladding glass to achieve an appropriate numerical aperture in said waveguide structure.

In a waveguide structure comprising a core glass demonstrating a high refractive index surrounded by a cladding glass demonstrating a lower refractive index, the improvement comprising a core glass consisting of a barium-modified, germanium gallium sulfide glass and a cladding glass also consisting of a barium-modified, germanium gallium sulfide glass, but wherein the barium content of said core glass is sufficiently higher than the barium content of said cladding glass to impart a sufficient difference between the refractive index of said core glass and said cladding glass to achieve an appropriate numerical aperture.