Board-level optical interconnection and signal distribution using embedded thin-film optoelectronic devices

Optical interconnection and signal distribution at the backplane, board, and substrate level can be implemented using thin-film active optoelectronic devices embedded in polymer waveguide structures. These active embedded devices eliminate the need for optical beam turning to and from photodetectors; and emitters, respectively, for inputs and outputs to the substrate waveguides. In this paper, optical interconnections using fully embedded thin-film metal-semiconductor-metal (MSM) photodetectors in polymer optical waveguides are demonstrated, and the experimental characterization of these thin-film MSMs embedded in polymer waveguides is reported. To illustrate the potential for high-level signal distribution at the backplane, board, and substrate levels, a 1 x 4 balanced multimode interference (MIMI) coupler has also been demonstrated in a photoimageable polymer for the first time. Finally, a 1 x 4 thin-film MSM photodetector array has been embedded in the output arms of the a photoimageable polymer MMI for the first time, and the MSM array photocurrent outputs from the 4 arms show that highly balanced optical signal distribution has been achieved.