| CPC G02B 6/12004 (2013.01) [H01L 23/481 (2013.01); G02B 2006/12038 (2013.01); G02B 2006/12102 (2013.01); G02B 2006/12121 (2013.01)] | 11 Claims |

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1. A substrate comprising:
a core of glass;
alternating layers of dielectric and conductive traces on either side of the core, wherein:
the core comprises a waveguide having a first endpoint on a first side of the core, and a second endpoint on a second side of the core, and
the first side is orthogonal to the second side; and
TGVs through the dielectric and the core, wherein the TGVs electrically couple a third side of the substrate with a fourth side of the substrate opposite to the third side.
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