Fully Embedded Board-Level Optical Interconnects From Waveguide Fabrication to Device Integration

This paper presents the latest progress toward fully embedded board-level optical interconnects in the aspect of waveguide fabrication and device integration. A one-step pattern transfer method is used to form a large cross-section multimode waveguide array with 45$^{\circ}$ micromirrors by silicon hard molding method. Optimized by a novel spin-coating surface smoothing method for the master mold, the waveguide propagation loss is reduced to 0.09 dB/cm. The coupling efficiency of the metal-coated reflecting mirror, which is embedded in the thin-film waveguide, is simulated by an $M ^{2}$ factor revised Gaussian beam method and is experimentally measured to be 85%. The active optoelectronic devices, vertical surface emitter lasers and p-i-n photodiodes, are integrated with the mirror-ended waveguide array and successfully demonstrate a 10 Gbps signal transmission over the embeddable optical layer.