Optical Coupler

Abstract

A semiconductor photonic device includes a substrate, facet(s), and optical coupler(s) associated with the facet(s). Each optical coupler can couple an electromagnetic field incident on the respective facet towards the substrate as the electromagnetic field proceeds into the semiconductor photonic device. In some examples, each coupler has waveguides extending in a longitudinal direction and at least partly encapsulated within corresponding cladding layers. A first waveguide extends farther from the facet in the longitudinal direction than does a second waveguide. The second waveguide is located farther above the silicon substrate than is the first waveguide. The coupler can include a stack of waveguide assemblies. A lower waveguide assembly can include one waveguide. An intermediate or upper waveguide assembly can include multiple waveguides. In some examples, at least one waveguide tapers along its length.

1 - 20 . (canceled) 
     
     
         21 . A device, comprising:
 a semiconductor substrate;   a first cladding layer arranged over the semiconductor substrate and having a relatively lower refractive index; and   a plurality of waveguide assemblies arranged in a stack over the first cladding layer, the plurality of waveguide assemblies comprising:
 a lower waveguide assembly arranged over the first cladding layer and comprising:
 a lower cladding layer having a relatively lower refractive index; and 
 a tapered lower waveguide at least partly encapsulated in the lower cladding layer and having a relatively higher refractive index; 
 
 at least one intermediate waveguide assembly arranged over a preceding waveguide assembly of the plurality of waveguide assemblies, each intermediate waveguide assembly comprising:
 a respective cladding layer having a relatively lower refractive index; and 
 at least one intermediate waveguide at least partly encapsulated in the respective cladding layer and having a relatively higher refractive index; and 
 
 an upper waveguide assembly arranged over an uppermost of the at least one intermediate waveguide assembly, the upper waveguide assembly comprising:
 an upper cladding layer having a relatively lower refractive index; and 
 at least two upper waveguides spaced apart laterally, each of the at least two upper waveguides at least partly encapsulated in the upper cladding layer and having a relatively higher refractive index, 
 
   wherein a first waveguide of the at least one intermediate waveguide or of the at least two upper waveguides tapers along a length of the selected waveguide.   
     
     
         22 . The device according to  claim 21 , wherein:
 the semiconductor substrate comprises crystalline silicon or a III-V semiconductor;   the first cladding layer comprises buried oxide;   the respective cladding layers of the at least one intermediate waveguide assembly comprise silicon oxide;   the intermediate waveguide comprises silicon nitride; or   the at least two upper waveguides comprise silicon nitride.   
     
     
         23 . The device according to  claim 21 , further comprising an active unit connected with the lower waveguide. 
     
     
         24 . The device according to  claim 21 , wherein the at least one intermediate waveguide assembly comprises at least:
 a first intermediate waveguide assembly comprising at most two intermediate waveguides of the corresponding at least one intermediate waveguide; and   a second intermediate waveguide assembly arranged over the first intermediate waveguide assembly and comprising at least three intermediate waveguides of the corresponding at least one intermediate waveguide.   
     
     
         25 . The device according to  claim 21 , wherein the at least one intermediate waveguide assembly comprises at least two intermediate waveguide assemblies, each comprising at least three intermediate waveguides of the corresponding at least one intermediate waveguide. 
     
     
         26 . The device according to  claim 21 , wherein a second waveguide of the at least one intermediate waveguide or of the at least two upper waveguides approaches at least a second waveguide of the at least two intermediate waveguides or of the at least two upper waveguides along a length of the first waveguide. 
     
     
         27 . The device according to  claim 21 , wherein a second waveguide of the lower waveguide, the at least one intermediate waveguide, or the at least two upper waveguides comprises at least two taper sections having respective, different rates of width taper as a function of distance along a longitudinal axis of the first waveguide. 
     
     
         28 . The device according to  claim 21 , wherein:
 the lower waveguide comprises a first taper section, followed by a first non-taper section, followed by a second taper section along a longitudinal axis of the lower waveguide;   the at least one intermediate waveguide assembly comprises a first intermediate waveguide assembly arranged over the lower waveguide assembly and comprising a first intermediate waveguide;   the first intermediate waveguide comprises a second non-taper section, followed by a third taper section, followed by a third non-taper section along a longitudinal axis of the first intermediate waveguide;   the first taper section and the second non-taper section are intersected by a first line substantially perpendicular to the longitudinal axis of the lower waveguide;   the first non-taper section and the third taper section are intersected by a second line substantially parallel to the first line and spaced apart from the first line; and   the second taper section and the third non-taper section are intersected by a third line substantially parallel to the first line and spaced apart from the first line and from the second line.   
     
     
         29 . The device according to  claim 21 , wherein the lower waveguide has a higher index of refraction than at least one of the intermediate waveguides. 
     
     
         30 . A device comprising:
 a substrate; and   an optical coupler comprising a plurality of waveguide assemblies arranged over the substrate, the plurality of waveguide assemblies comprising:
 a first waveguide assembly comprising a first cladding layer and one or more first waveguides that are at least partly encapsulated within the first cladding layer; and 
 a second waveguide assembly arranged over the first waveguide assembly, the second waveguide assembly comprising a second cladding layer and one or more second waveguides that are at least partly encapsulated within the second cladding layer 
   
     
     
         31 . The device according to  claim 30 , wherein a third waveguide of the one or more first waveguides or of the one or more second waveguides tapers along a length of the third waveguide. 
     
     
         32 . The device according to  claim 30 , wherein:
 the one or more first waveguides have respective first refractive indices;   each of the respective first refractive indices is higher than a refractive index of the first cladding layer;   the one or more second waveguides have respective second refractive indices; and   each of the respective second refractive indices is higher than a refractive index of the second cladding layer.   
     
     
         33 . The device according to  claim 30 , further comprising an active unit arranged over the substrate, wherein the optical coupler is disposed at least partly between a facet of the optical coupler and the active unit. 
     
     
         34 . The device according to  claim 33 , further comprising a processor operatively coupled to the active unit, the processor configured to at least transmit or receive data. 
     
     
         35 . The device according to  claim 33 , wherein:
 the device further comprises:
 a plurality of active units, the plurality of active units comprising the active unit; 
 a plurality of facets; and 
   a plurality of optical couplers disposed, respectively, between the plurality of active units and the plurality of facets, the plurality of optical couplers comprising the optical coupler,   each optical coupler of the plurality of optical couplers defines a respective longitudinal axis; and   each optical coupler of the plurality of optical couplers comprises:
 a third waveguide arranged relatively closer to the respective active unit in the longitudinal direction and relatively closer to the substrate; and 
 a fourth waveguide arranged relatively farther from the respective active unit in the longitudinal direction and relatively farther from to the substrate. 
   
     
     
         36 . The integrated circuit according to  claim 35 , wherein:
 the respective third waveguides of the plurality of optical couplers are arranged in the first cladding layer; and   the respective fourth waveguides of the plurality of optical couplers are arranged in the second cladding layer.   
     
     
         37 . An assembly comprising:
 a semiconductor photonic device having:
 a substrate; 
 a plurality of facets; and 
 a plurality of optical couplers associated with respective facets of the plurality of facets; and 
   a plurality of single-mode optical fibers disposed in a splice configuration with respect to respective facets of the plurality of facets,   wherein:   each optical coupler of the plurality of optical couplers comprises:
 a plurality of waveguide assemblies arranged over the substrate, the plurality of waveguide assemblies comprising:
 a first waveguide assembly comprising a first waveguide at least partly encapsulated within a first cladding layer; and 
 a second waveguide assembly arranged over the first waveguide assembly, the second waveguide assembly comprising a second waveguide at least partly encapsulated within a second cladding layer, 
 
   each optical coupler of the plurality of optical couplers comprises means for coupling an electromagnetic field incident on the facet towards the substrate as the electromagnetic field proceeds into the semiconductor photonic device, and   a selected waveguide among the respective first waveguides and the respective second waveguides tapers along a length of the selected waveguide.   
     
     
         38 . The assembly according to  claim 37 , further comprising a V-groove array configured to retain the single-mode optical fibers in position with respect to the respective facets. 
     
     
         39 . The assembly according to  claim 37 , wherein the respective second waveguide is farther from the substrate than the respective first waveguide of the selected waveguide assembly and extends closer to the respective facet than the respective first waveguide. 
     
     
         40 . The assembly according to  claim 39 , wherein a first index of refraction of the respective first waveguides is higher than a second index of refraction of the first cladding layer, and a third index of refraction of the respective second waveguides is higher than a fourth index of refraction of the second cladding layer.