VCSEL arrays for high speed optical links

VCSEL arrays are attractive low-cost high-speed sources for free space and fiber coupled links. We discuss applications and performance limits of 1D and 2D VCSEL arrays. At Avalon Photonics Ltd. a broad variety of devices (up to 16/spl times/16) is developed and fabricated. Top and bottom emitting arrays offer new perspectives in optical and electrical packaging and are therefore of high interest for short haul parallel optical links, board-to-board and on-board ultra high-speed optical interconnects. Bandwidth requirements are increasing rapidly. The limits of VCSEL arrays in terms of modulation speed are analyzed and RF device optimization is discussed. Device and package limitations have to be considered. Important system level implications are also pointed out. Results of 850 nm multitransverse mode VCSEL arrays demonstrating excellent uniformity, low threshold current, high modulation efficiency and excellent multi-gigabit performance are presented. The paper ends with a discussion of future prospects in the field.