Devices having low loss curved or tapered optical waveguides

Claim 3

Device of claim 1 in which said second profile of refractive index varies as a function of path length along said waveguide.

Claim 4

Device of claim 1 in which said second profile of refractive index results from at least one prism-shaped feature having raised refractive index.

Claim 5

Device of claim 3 in which said second profile of refractive index results from a plurality of prism-shaped features having raised refractive index.

Claim 6

Device of claim 4 in which said plurality of features is crown-shaped.

Claim 7

Device of claim 1 in which said second profile is non-zero over a domain which includes a significant portion of said substrate in at least one direction transverse to said optical path length.

Claim 8

Device of claim 6 in which a width of said domain is in the range of from 1.1 to 4 times a width of said waveguide.

Claim 9

Device of claim 7 in which a width of said domain is in a range of from 1.5 to 3 of a width of said waveguide.

Claim 10

Device of claim 1 in which said second profile of refractive index results from at least one lens-shaped feature having raised refractive index.

Claim 11

Device of claim 9 in which said lens-shaped feature has a divergent effect.

Claim 12

Device of claim 9 in which said lens-shaped feature has a convergent effect.

Claim 13

Method for making an optical device, said method comprising establishing a region of raised index of refraction in a body of optically transparent material, said region of raised index of refraction comprising a waveguide, said region of raised refractive index having a cross-sectional profile of refractive index which can be represented as a sum of a first profile of refractive index and a second profile of refractive index, said first profile of refractive index being such as to result in guidance of an electromagnetic wave at least in the absence of bends or tapers, and said second profile of refractive index being chosen so as to essentially equalize optical path lengths along the optical axis and other significant optical paths around a bend or through a taper, whereby radiation loss at said bend or taper is minimized.

Claim 14

Method for making an optical device, said method comprising establishing a region of raised index of refraction in a body of optically transparent material, said region of raised index of refraction comprising a waveguide, said region of raised refractive index having a cross-sectional profile of refractive index which can be represented as a sum of a first profile of refractive index and a second profile of refractive index, said first profile of refractive index being such as to result in guidance of an electromagnetic wave at least in the absence of bends or tapers, and said second profile of refractive index being chosen so as to essentially equalize optical path lengths along the optical axis and other significant optical paths around a bend or through a taper, whereby radiation loss at said bend or taper is minimized.

Claim 15

Method of claim 12 in which said region is established by diffusion.

Claim 16

Method of claim 12 in which said region is established by ion implantation.

Claim 17

Method of claim 12 in which said region is established by ion exchange.