METHOD AND APPARATUS FOR OPTICAL BEAM ALIGNMENT DETECTION AND CONTROL

摘要

Methods and apparatus are provided for detection and control of multiple-axis active alignment for a free-space-coupled single-mode fiber-optic transmission system that automatically optimizes the coupling through the system. In a specific embodiment, a measurement of coupled power is made and error signals are used to control actuation via four axes of beam steering element to null four generally orthogonal alignment errors of the beam between the input (12) and output fibers (14). The four alignment errors are detected using a synchronous-detection approach. A feedback control system (100) nulls the four errors.