Gigabits-per-Second Signal Transmission from Single-Mode Vertical-Cavity Surface-Emitting Laser via Thin-Film Waveguide for Wavelength-Division-Multiplexing Optical Interconnect Board

A wavelength-division-multiplexing (WDM) optical interconnect board providing broad-band transmission from a two-dimensional (2D) array of vertical-cavity surface-emitting lasers (VCSELs) to a 2D array of photodetectors is one of the attractive candidates for constructing future ultrahigh performance signal processing systems. Focusing grating couplers and distributed Bragg reflectors were integrated into a thin-film glass waveguide to form free-space-wave optical add/drop multi/demultiplexers required for the WDM optical interconnect board. A single-mode VCSEL was placed at the focal point of a focusing grating coupler, and a diverging wave from VCSEL was coupled and collimated into the waveguide. After 15 mm propagation, the guided wave was dropped by an optical drop demultiplexer to a focusing wave in free space. VCSEL was driven directly by a pulse pattern generator and the transmitted signal was detected. An open eye diagram of a 1 Gbps pseudo-random-binary-sequence non-return-to-zero signal was confirmed.