We present characteristics of 850-nm oxide confined vertical-cavity surface-emitting lasers (VCSELs) developed for applications in optical parallel data links and free-space optical interconnects. Low threshold currents of less than 200 ltA, wall-plug efficiencies approaching 30%, operating voltages of less than 2 V for 1 mW of optical power, and operation over a wide temperature range, up to 190°C, are demonstrated. We optimized VCSEL arrays for operation at elevated temperatures for use in dense free-space interconnects. Excellent performance uniformity -optical power of 1±0.1 mW at a drive current of 3 mA -across a 20x20 array was achieved at 75°C. We integrated two-dimensional top emitting VCSEL arrays with topilluminated metal-semiconductor-metal (MSM) detectors for future use with CMOS integrated circuits. We discuss design issues encountered in VCSEL-based modules for optical interconnects.