VCSEL Arrays of 10 Gb/s Multimode Fiber Optical Interconnects

In this paper, we report on some transmitter and optical fiber technologies for 10 Gb/s speed datacom systems. Primarily to enable direct flip-chip integration with silicon CMOS circuits for highly parallel interchip interconnects, we have fabricated two-dimensional vertical-cavity surface-emitting laser (VCSEL) arrays features 4*8 elements on a 250microns pitch. Arrays emitting in the 980 nm spectral region exhibit excellent homogeneity and operation data like 0.8 mA threshold current, below 1.5 V threshold voltage, 1 mW output power at mA current, and more than 35% conversion efficiency in the 2 to 5 mW power range. Bottom emission of 850 nm arrays is enable by etching holes into the opaque GaAs substrate. Due to less efficient heat removal, devices are currently limited to about 2 mW light output at 6 mA current. Top-emitting 850 nm array elements have been employed for high-speed data transmission experiments. First we describe the characteristics of a new 50microns core diameter silica multimode fiver that allows for 10 Gb/s data rate operation over a record distance of 1.6 km. Finally, a 9 Gb/s transmission experiment over 100 m length of a rather promising perfluorinated plastic optical fiber for low-cost data links is presented.