Compact VCSEL-based laser array communications systems for improved data performance in satellites

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.