Patent ID: 8731343
Filing Date: 2014-05-20
Classification: G02B

Abstract:
1. An optical printed circuit board, comprising: at least one optical waveguide for carrying optical signals on the optical printed circuit board, the waveguide comprising an optical core surrounded by an optical cladding material; and a trench formed adjacent to the at least one optical waveguide, wherein the trench contains a matrix material having suspended therein a light absorbent material to absorb light that strays from the at least one waveguide, in which the light absorbent material is selected to be light absorbent over a range of wavelengths from about 600 nm to about 1700 nm; and in which a concentration of the light absorbent material within the trench is sparse such that a combination of the light absorbent material with the matrix provides a heterogeneous mixture of matrix material with occasional light absorbent material; wherein a region extending from a boundary between the trench and the optical cladding material up to approximately 15 microns into the trench has significantly lower concentration of light absorbent material than a remainder of the trench.