Back side via vertical output couplers
First Claim
1. A method of forming a vertical output coupler for a waveguide, the waveguide being formed of a waveguide material that is disposed within a layer stack on a front surface of a wafer, wherein the layer stack includes a cladding layer atop the waveguide, the method comprising:
- defining a via photoresist mask on a back surface of the wafer, wherein;
the via photoresist mask exposes a via shape on the back surface of the wafer and protects other surfaces of the back surface of the wafer, andetching through a portion of the wafer where the via shape is exposed, to form a via that exposes the waveguide material;
etching the waveguide material to remove at least a first portion of the waveguide, wherein etching the waveguide material forms at least a first tilted plane in the waveguide material;
removing the via photoresist mask;
coating the first tilted plane with one or more reflective layers, to form a tilted mirror in contact with the first tilted plane in the waveguide material;
etching a recess in the cladding layer to expose the waveguide before forming the antireflective coating; and
forming an antireflective coating on the front surface of the wafer such that the light deflected by the tilted mirror passes through the antireflective coating;
wherein the tilted mirror forms the vertical output coupler such that light propagating through the waveguide is deflected by the tilted mirror, exiting the waveguide;
and wherein defining the photoresist mask comprises registering the via shape with the recess so that when etched, the tilted mirror forms within lateral and horizontal bounds of the recess.
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Accused Products
Abstract
A method forms a vertical output coupler for a waveguide, formed of waveguide material and disposed within a layer stack on a top surface of a wafer. The method includes etching through a portion of the wafer to form a via that exposes the waveguide material, and etching the waveguide material to remove at least a first portion of the waveguide. The etching forms a tilted plane in the waveguide material. The method further includes coating the first tilted plane with one or more reflective layers, to form a tilted mirror in contact with the first tilted plane in the waveguide material. The tilted mirror forms the vertical output coupler such that light propagating through the waveguide is deflected by the tilted mirror, and exits the waveguide.
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Citations
17 Claims
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1. A method of forming a vertical output coupler for a waveguide, the waveguide being formed of a waveguide material that is disposed within a layer stack on a front surface of a wafer, wherein the layer stack includes a cladding layer atop the waveguide, the method comprising:
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defining a via photoresist mask on a back surface of the wafer, wherein; the via photoresist mask exposes a via shape on the back surface of the wafer and protects other surfaces of the back surface of the wafer, and etching through a portion of the wafer where the via shape is exposed, to form a via that exposes the waveguide material; etching the waveguide material to remove at least a first portion of the waveguide, wherein etching the waveguide material forms at least a first tilted plane in the waveguide material; removing the via photoresist mask; coating the first tilted plane with one or more reflective layers, to form a tilted mirror in contact with the first tilted plane in the waveguide material; etching a recess in the cladding layer to expose the waveguide before forming the antireflective coating; and forming an antireflective coating on the front surface of the wafer such that the light deflected by the tilted mirror passes through the antireflective coating; wherein the tilted mirror forms the vertical output coupler such that light propagating through the waveguide is deflected by the tilted mirror, exiting the waveguide; and wherein defining the photoresist mask comprises registering the via shape with the recess so that when etched, the tilted mirror forms within lateral and horizontal bounds of the recess. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of forming a waveguide with a vertical output coupler, the method comprising:
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generating a layer stack on a front surface of a wafer, a back surface of the wafer being opposite the front surface, wherein the layer stack includes; a first cladding layer, a crystalline waveguide layer, and a second cladding layer, wherein the first cladding layer is disposed nearest a substrate of the wafer, the second cladding layer is disposed furthest from the substrate and the crystalline waveguide layer is disposed between and in contact with both the first cladding layer and the second cladding layer; forming the waveguide by; using photolithography and etching on the front surface to form a shoulder region in the crystalline waveguide layer, using photolithography on the front surface to define a ridge within the shoulder region, partially etching the shoulder region of the crystalline waveguide layer except where the ridge is defined, and depositing a second cladding layer over the ridge and the partially etched shoulder region; using photolithography and etching on the front surface to form a recess region in the second cladding layer, wherein the second cladding layer is removed from at least the ridge within the recess region; depositing an antireflective coating on the front surface of the wafer such that the antireflective coating is adjacent to and in contact with the ridge within the recess region; depositing a top side protective layer over the antireflective coating; removing the top side protective layer within at least part of the recess region, so as to expose the antireflective coating; defining a via shape in a photoresist mask on the back surface of the wafer, wherein the via shape defined by the photoresist mask is registered with respect to features on the front surface, wherein; the photoresist mask exposes the via shape on the back surface of the wafer and protects other surfaces of the back surface of the wafer, and the via shape is vertically aligned, through the wafer, with the recess region; etching through the substrate and the first cladding layer where the via shape is exposed, to form a via that exposes the waveguide material; etching the waveguide material to remove at least a first portion of the waveguide, using an etchant that forms at least a first tilted plane in the crystalline waveguide layer; removing the via photoresist mask; and coating the first tilted plane with one or more reflective layers, to form a tilted mirror in contact with the first tilted plane in the waveguide material, wherein the tilted mirror forms the vertical output coupler such that light propagating through the waveguide is deflected by the tilted mirror, and exits the waveguide through the antireflective layer. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification