Lucent Technologies Inc.

Harold Yoonsung Hwang

Sang-Wook Cheong

Federico Capasso

Alfred Yi Cho

Deborah Lee Sivco

Claire F Gmachl

Albert Lee Hutchinson

Richart Elliott Slusher

James Nelson Baillargeon

Gadi Lenz

Alessandro Tredicucci

Arthur Mike Sergent

Malcolm Ellis Lines

Bertram Josef Batlogg

David Anthony Muller

Roberto Paiella

Markus J P Siegert

Akira Ohtomo

The present invention provides a semicondctor device that includes a conductor comprised of first and second layers of perovskite that have different stoichiometric compositions. The conductors provide a good template for the formation of dielectric layers thereon and are resistant to oxidizing environments used in semiconductor processing.

Oxidation-resistant conducting perovskites

An optical device comprises a body of ferroelectric material exhibiting an effective electro-optic coefficient (r ) and an optical loss (&agr;), with the body being adapted for the propagation of optical radiation at a wavelength &lgr; through it, and means for applying an electric field to the body in order to alter the refractive index therein, characterized in that the body is polycrystalline and has an average grain size such that r is relatively high and &agr; is relatively low, both at &lgr; . In a preferred embodiment the body has an average grain size that is less than about &lgr; /10, preferably in the range of approximately 8-20 nm, which is especially well suited for devices operating at near infrared wavelengths in the range of about 1000-1600 nm. Illustratively, the ferroelectric body is a perovskite material such as barium titanate or lithium niobate.

Polycrystalline ferroelectric optical devices

In a mesa geometry semiconductor laser, a patterned dielectric coating used to define the stripe geometry contact on the top the mesa and to provide significant waveguiding comprises a chalcogenide glass. Applications to intersubband (e.g., quantum cascade) lasers are specifically described.

Mesa geometry semiconductor light emitter having chalcogenide dielectric coating

Waveguides according to this invention have a chalcogenide glass core that comprises Se and one or both of As and Ge, and further comprises one or more dopant elements selected from the elements that cause a change in optical energy gap E,of the glass core. The amount of dopant is selected such that E,is equal to or less than a 2-photon energy 2h&ngr;, where h is Planck's constant and &ngr;&equals;c/&lgr;, where c is the speed of light in vacuum and &lgr; is an operating wavelength. The dopant elements furthermore are selected such that the chalcogenide glass core has a nonlinear refractive index n,greater than 200n,(SiO,), where n,(SiO,) is the nonlinear index of silica at &lgr;. Typically, &lgr; is about 1.55 &mgr;m. Exemplary, the dopant elements are selected from Sb, Bi, Sn, Pb, In, Tl, Cu, Ag and S. Currently preferred dopants are Te, Sb, Tl, Cu and Ag. Waveguides according to the invention are advantageously used in all-optical switches, optical logic elements and other means for optical processing of optical pulses.

Article comprising a planar optical waveguide with optically non-linear core

An article that uses a magnetoresistive material comprising one or more CrO.sub.2 grains having an insulating material, advantageously Cr.sub.2 O.sub.3, along at least a portion of the grain boundary or boundaries, the magnetoresistive article advantageously exhibiting a magnetoresistance ratio greater than 12% at 5K and 20 kOe.

Article comprising magnetoresistive material

Magnetoresistive elements according to this invention comprise magnetically soft material in close proximity to the magnetoresistive material, exemplarily a perovskite manganite. The combination results in magnetic field 'amplification', with large resistance changes attainable at relatively low applied fields. The invention exemplarily is embodied in magnetic sensors, e.g., magnetoresistive read/write heads.

Article comprising a manganite magnetoresistive element and magnetically

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Jersey City, NJ, United States of America

Harold Yoonsung Hwang