Photo-robotic positioning of quaterwaveplates for integrated optics

High positioning accuracy is a crucial need to perform successfully complex tasks such as micromanipulation and microassembly. This especially enables to provide high performances or to propose new functionalities/products, notably for integrated optical devices. The objective of the letter is to align two optical structures in multi-DOF way with very high accuracy. The originality of the approach relies on robotic positioning associated with the use of interfered reflected light irradiance as a feedback signal rather than transmitted power. Fabry–Perot interference principle is especially used to provide a fast and high accurate measurement. An opto-mechanical model that relates the optical component poses with the interfered reflected light is proposed. Experimental results are investigated based on a robotic multi-DOF platform, used to relatively align an optical component to an optical fiber. The obtained results establish that the model fits with experiments with a standard deviation below 0.0281◦. This model associated with an automated positioning strategy shows that it is possible to maximize reflectivity within less than 6 s, including multi-DOF angular misalignments identification and compensation.