Relaxed tolerance adiabatic coupler for optical interconnects

Abstract

An optical arrangement includes an optical printed circuit board (OPCB) having at least a first optical waveguide having a first end located on the OPCB. The optical arrangement also includes at least one photonic integrated circuit (PIC) mounted to the OPCB. The PIC includes a second optical waveguide. The first waveguide has a second end located on a portion of the second waveguide to optically couple light between the PIC and the first waveguide. The portion of the second waveguide on which the second end of the first waveguide is located has an inverse taper. The inverse tapered portion is defined by a plurality of segments. The segments of the inverse tapered portion each have a length and a taper rate that causes each segment to make an equal contribution to any radiation losses in the mode transformation of light being coupled between the first and second waveguides.

1 . An optical coupler, comprising:
 a photonic integrated circuit (PIC) having at least one tapered-waveguide output port; and   a second waveguide being sufficiently close to the tapered-waveguide output port to enable an adiabatic transition of an optical signal from the at least one tapered-waveguide output port to the second waveguide.   
     
     
         2 . The optical coupler of  claim 1 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, at least one of the segments being a linear taper and the inverse taper of at least another of the segments being an exponential taper. 
     
     
         3 . The optical coupler of  claim 1 , wherein the tapered-waveguide output port is an Si-based or Si 3 N 4 -based waveguide. 
     
     
         4 . The optical coupler of  claim 1 , wherein the second optical waveguide is a prefabricated polymer waveguide. 
     
     
         5 . The optical coupler of  claim 1 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, wherein the segments of the inverse tapered portion each have a length and a taper rate that causes each segment to make an equal contribution to any radiation losses in the mode transformation of light being coupled between the first and second optical waveguides. 
     
     
         6 . The optical coupler of  claim 1 , wherein the second waveguide has a core thickness less than 5 microns. 
     
     
         7 . The optical coupler of  claim 1 , wherein the second waveguide and the at least one tapered waveguide define an angle of less than 10 degrees between them. 
     
     
         8 . The optical coupler of  claim 1 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, all of the segments being a linear taper. 
     
     
         9 . The optical coupler of  claim 1 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, all of the segments being an exponential taper. 
     
     
         10 . An optical coupler, comprising:
 a photonic integrated circuit (PIC) having at least one tapered-waveguide output port; and   a second waveguide located within 1000 nm of, and substantially in parallel with, the at least one tapered-waveguide output port to enable an adiabatic transition of an optical signal from the at least one tapered-waveguide output port to the second waveguide, wherein the second waveguide has a core thickness less than 5 microns.   
     
     
         11 . The optical coupler of  claim 10 , wherein the second waveguide is located within 500 nm of the at least one tapered-waveguide output port. 
     
     
         12 . The optical coupler of  claim 10 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, at least one of the segments being a linear taper and the inverse taper of at least another of the segments being an exponential taper. 
     
     
         13 . The optical coupler of  claim 10 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, all of the segments being a linear taper. 
     
     
         14 . The optical coupler of  claim 10 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, all of the segments being an exponential taper. 
     
     
         15 . The optical coupler of  claim 10 , wherein the tapered waveguide output port is an Si-based or Si 3 N 4 -based waveguide. 
     
     
         16 . The optical coupler of  claim 10 , wherein the second optical waveguide is a prefabricated polymer waveguide. 
     
     
         17 . The optical coupler of  claim 10 , wherein the tapered-waveguide output port includes an inverse tapered portion having a plurality of segments, wherein the segments of the inverse tapered portion each have a length and a taper rate that causes each segment to make an equal contribution to any radiation losses in the mode transformation of light being coupled between the first and second optical waveguides. 
     
     
         18 . The optical coupler of  claim 10 , wherein the second waveguide has a core and cladding, a refractive index difference between the core and the cladding being no more than 0.1. 
     
     
         19 . The optical coupler of  claim 7 , wherein the second waveguide has a core and cladding, a refractive index difference between the core and the cladding being no more than 0.3. 
     
     
         20 .- 32 . (canceled)