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A unique architecture for two-dimensional arrays of VCSELs that allow for simultaneous high-power output and highbandwidth modulation has been developed for a variety of applications. The arrays use integrated micro-lenses for beam shaping and control, and to enable incoherent beam combining to make compact, high-brightness sources with low coherence noise. The fabrication and performance of the laser arrays are reviewed and sample applications are discussed. VCSEL ARRAY TECHNOLOGYVertical Cavity Surface Emitting Lasers (VCSELs) have been used in short-wavelength multi-mode fiber optic communications systems for over twenty years. Individual devices have achieved efficient operation with modulation speeds in excess of 40 Gb/s at both the 850 nm and 980 nm wavelengths. 1,2 VCSELs have also been shown to be effective and robust in extreme temperature and radiation environments. 3,4 Large 2D arrays of VCSELs have been used as illuminators and for industrial thermal processing. 5,6 Single VCSEL devices generally operate at optical output powers of several mW, especially when designed for data rates of 10 Gb/s or higher. Large optical output powers have been attained by building simultaneously-addressed arrays of VCSELs on common substrates or on multiple substrates. 7,8 These arrayed devices are usually designed for low modulation bandwidth. The primary limiting factor is additive bulk capacitance when the individual VCSEL devices are combined into an array for parallel operation.Previously, we described a back-emitting VCSEL array technology that is scalable to >100 mW in power output, yet can be modulated at up to 10 Gb/s. 9 Here we present results that apply to the use of this approach in two-dimensional VCSEL arrays for short range NIR illumination and 3D flash LIDAR.

Compact, radiation-hardened free-space optical data links are enabled by two-dimensional VCSEL arrays that can be modulated at high data rates while being scaled to produce high power levels. The combination of high modulation speed and scalability of power is enabled by the use of arrays which are flip-chip mounted onto sub-mounts that contain electrical strip line waveguides to provide an impedance match for the VCSELs. For laser wavelengths in the 910 nm to 1020 nm range, the lasers can be back-emitting through the GaAs substrate, which enables the use of etched microlenses to manipulate the beams from the individual elements. This approach of using VCSELs in arrays is inherently reliable and radiation-hard. The resulting free space optical data links are particularly advantageous for space-borne applications where size, weight, and power are important factors. Performance characterization of links constructed with these lasers demonstrates their suitability for short distance to medium distance data transfer at up to 10 Gb/s.