Patent ID: 11275208

Abstract:
A method of forming an optical interconnect between first and second photonic chips located on an optical printed circuit board includes applying a flexible, freestanding film onto the first and second chips so that the film extends over a gap and/or step between the chips. The film includes a photosensitive layer having a refractive index that decreases by exposure to radiation and a backing layer. The film is exposed to a flood exposure having a radiation dosage penetrating the backing layer and only a surface sublayer of the photosensitive layer. After curing the film, the backing layer is removed so that the photosensitive layer remains on the first and second chips. The photosensitive layer is selectively exposed to a second radiation dosage to define waveguide core(s) in unexposed regions of the photosensitive layer below the surface sublayer. The photosensitive layer is heated to cure the selectively exposed portions.