Two-microlens coupling scheme with revolved hyperboloid sol-gel microlens arrays for high-power-efficiency optical coupling

In lightwave communications, the high-power-efficiency coupling between a laser diode (LD) and a single-mode fiber (SMF) is indispensable. This paper proposes an imaginative two-microlens-array (MLA) coupling scheme whereby two revolved hyperboloid MLAs were used back-to-back between the LD and the SMF, and a coupling efficiency of 83.4% (-0.79 dB) has been achieved. The study also employs a cost-effective fabrication method, with a combination of the sample-inverted reflow technique and the soft lithography replication method, to fabricate revolved hyperboloid MLAs in inorganic-organic hybrid silica-zirconia sol-gel material. As a result, the fabricated MLAs have excellent smooth profiles and negligible discrepancies from the profiles of the ideal hyperboloid MLAs.