An Oriented-Dependence-Microlens Visual Alignment and Packaging for Lasers Coupling to PMFs

Abstract

An oriented-dependence-microlens (ODM) visual alignment and packaging for lasers coupling to polarizationmaintaining-fibers (PMFs) is proposed and demonstrated. The ODM is fabricated by automatic grinding and accurate positioning techniques. The position accuracy of the grinding machine is ±1°, which is less than the aligned and fabricated angular tolerance of ±2°for the ODM necessary to achieve both high coupling of 80% and high polarized extinction ratio of 30 dB. This indicates that the ODM endface of the fast axis can be visually observed and then surface feature aligned to the axis of the laser polarization direction. A practical package of laser/PMF with compact size and a few components employing the ODM is also demonstrated. The proposed ODM with visually precise surface feature alignment to achieve both high coupling and polarization is beneficial for the application of laser/PMF modules for use in high-precision fiber optic gyroscopes and many high-performance and low-cost lightwave interconnections. IndexTerms-Polarization-maintaining fiber, visually alignment, microlens, fiber optic gyroscope.