Broadband optical via
AssigneeLittle Optics, Inc.
InventorBrent E. Little
Life of this patent
Estimating the term…
Abstract
A broadband optical via provides a low loss interconnection between waveguides in two vertically adjacent planar waveguiding layers. Two waveguides, one in each planar layer, evanescently interact over an interaction length, and substantially all of the power on one waveguide is transferred to the second waveguide. The relative detuning between waveguides is varied along the interaction region by tapering the width of one or both guides along the direction of propagation. The interaction strength is also varied by varying the physical separation between the two waveguides such that the interaction approaches zero near the two ends of the interaction length. The performance of the broadband optical via is fabrication tolerant, polarization tolerant, wavelength tolerant, and dimensionally tolerant.
Claims12
An optical via comprising:
- (a) a first waveguide in a first planar layer, said first waveguide having a first refractive index value and an input end, and supporting an optical mode with a first effective index value,
- (b) a second waveguide in a second planar layer, said second waveguide having a second refractive index value and an output end, and supporting a second optical mode with a second effective index value,
- (c) said first mode of first waveguide and said second mode of second waveguide evanescently interacting over an interaction length, and
- (d) means for adjusting the magnitude of said mode-to-mode evanescent interaction, adjusting the detuning between said effective indexes of said first and second modes, and adjusting said interaction length, in such a way as to effect broadband and substantially complete optical power transfer from said input end of the first waveguide to said output of the second waveguide;
- wherein the optical via introduces less than 0.1 dB of excess loss in a band of wavelengths between 1510 nm and 1620 nm.
A means for optically connecting two waveguides on two different planar layers by an optical via comprising
- (a) providing a first waveguide in a first planar layer, said first waveguide having a first refractive index value and an input end, and supporting an optical mode with a first effective index value,
- (b) providing a second waveguide in a second planar layer, said second waveguide having a second refractive index value and an output end, and supporting a second optical mode with a second effective index value,
- (c) providing a region where said mode of the first waveguide on the first layer evanescently interacts with said mode of the second waveguide on the second layer over an interaction length, and
- (d) means for adjusting the magnitude of said mode-to-mode evanescent interaction, adjusting the detuning between said effective indexes of said first and second modes, and adjusting said interaction length, in such a way as to effect broadband and substantially complete optical power transfer from said input end of the first waveguide to said output end of the second waveguide;
- wherein the optical via introduces less than 0.1 dB of excess loss in a band of wavelengths between 1510 nm and 1620 nm.
Dependencies are inferred from the claim text.