New Scheme of Microlens Fiber Array for High Coupling Efficiency in Si-Photonics Module

A new scheme of microlens 4-fiber array (M4FA) for high-coupling efficiency in Si-photonics module employing automatic packaging a silicon V-groove array and microlens fibers is demonstrated. The silicon V-groove array was fabricated by KOH wet etching. The microlens fibers were precisely controlled by automatic grinding and calibrated spin-on-glass (SOG) liquid electrostatic coating to achieve the required minor radius of curvature of 1.3- $\mu \text{m}$ for achieving high coupling efficiency. In comparison with other microlens fabrication by mechanical grinding and multiple fusing techniques, the proposed M4FAs enable to adjust the fiber offset, radius of curvature, and alignment tolerance by SOG coating after fiber grinded, resulting in high-average coupling efficiency of 60% from Si-photonics module to M4FA. The newly developed M4FA by automatic grinding and calibrated SOG coating is beneficial for the applications of Si-photonics modules use in many low-cost and high-performance light-wave interconnections.