Patent ID: 7853108

Claim:
A device comprising: a strongly confining optical waveguide including: a first core region disposed over a substrate, the first core region having a first substantially rectangular cross-section and comprising a first core material, the first core material comprising a semiconductor and being substantially transparent within an operating wavelength range having a first free-space center wavelength selected from the range of 500 nm to 3000 nm; and a first cladding region surrounding the first core region, the first cladding region (i) comprising at least one cladding material having a refractive index, and (ii) having a first maximum cladding refractive index equal to the largest refractive index of the at least one cladding material, wherein a core refractive index of the first core material is at least 1.5 times the first maximum cladding refractive index, wherein the first rectangular cross-section has a first aspect ratio A R defined by a ratio of a width of the first rectangular cross-section to a height of the first rectangular cross-section, the first aspect ratio is at least 5:1 and at most 20:1, and a height of the first core region is between 1/150 and 1/10 of the first free-space center wavelength, and wherein the waveguide comprises a section having a bending radius between twice and ten times the first free-space center wavelength.