Design of hybrid micro-diffractive-refractive optical element with wide field of view for free space optical interconnections

A new design is presented to achieve a hybrid micro-diffractiverefractive lens with wide field of view (WFOV) of 80 degrees integrated on backside of InGaAs / InP photodetector for free space optical interconnections. It has an apparent advantage of athermalization of optical system which working in large variation of ambient temperature ranging from -20 degrees C to 70 degrees C. The changing of focal length is only 0.504 m in the ambient temperature range with the hybrid microlens, which opto-thermal expansion coefficient matches with thermal expansion coefficient of AuSn solder bump used in corresponding flip-chip packaging system. The hybrid lens was designed via CODE-VTM professional software. The results show that the lens has good optical performance for the optical interconnection use.