The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 20, 1996
Filed:
Dec. 14, 1994
Richard A Soref, Newton Centre, MA (US);
Lionel Friedman, Holden, MA (US);
Abstract
Silicon-based laser diodes, optical amplifiers, electrooptical modulators, and photodetectors in which the active region consists of a pseudomorphic GeSn multiple quantum well stack. Each quantum well is tensile-strained Ge.sub.1-x Sn.sub.x layer sandwiched between compressively strained barriers of Ge.sub.1-y Sn.sub.y with x.about.0.1, x<y and y.about.0.15. The GeSn quantum wells have a strain-induced direct gap for strongly allowed band-to-band transitions in the infrared range. The quantum well stack is grown upon a relaxed SiGeSn alloy buffer portion whose composition is graded up from a lattice match at the silicon substrate interface to a Ge or GeSn composition at buffer's top surface. Doped cladding layers are added, so that the devices have a p-i-n diode structure. The monolithic integrated Column IV devices have a rib waveguide structure, where desired, and operate typically in the 2 to 3 micron wavelength range.