Optical waveguides for chip-to-chip  interconnects

A process has been developed for fabricating polymer multimode optical waveguides on a printed circuit board for chip-to-chip optical interconnects. In this process an excimer laser ablation is first used to fabricate a trench in the surface of the board. Then a computer controlled automatic dispenser is used to lay down two layers of UV curable polymers with appropriate indices of refraction to form the cladding and core of the waveguide. Input and output couplers are fabricated by excimer laser fabrication.


Polymer waveguide structure in a PCB fabricated by dispensing a cladding and core layer in an excimer laser-ablated trench in the PCB surface


Picture taken by time exposure of 633nm
light (for visibility in demo) guided in a
polymer optical waveguide fabricated on
a printed circuit board.


The MicroPen, a computer controlled automatic dispenser for laying down lines of solution that are then UV-cured into polymer optical waveguides.


Undercut facets fabricated by Excimer laser
ablation for mirror-like in-coupling to and out-
coupling from polymer waveguide..
Coupling efficiencies exceed 80%.

“Dispensed Polymer Waveguides and Laser-Fabricated Couplers for Optical Interconnects on PC Boards”  Yongzhang Leng, Victor Yun, Lisa Lucas, Warren N. Herman, Julius Goldhar, Applied Optics 46, pp. 602-610(2007).