Automation of multi-degree-of-freedom fiber-optic alignment using a modified simplex method

Automation of fiber-to-optic alignment is the key to reduce the cost of the packaging process for the manufacturing of fiber-optic devices. Due to its fast convergence and easy of implementation, the King's modified simplex method (MSM) seems suitable for the fiber-optic alignment automation. This paper presents the use of this method on automatic three-dimensional (3D) fiber-to-optic alignment. A series of experiments have been conducted for the 3D alignment of a single mode fiber coupled with laser diode (LD) on an active automated alignment machine. The performance of this method is investigated and relevant problems are discussed. It is found that the simplex method is difficult in handling the problem in which the optimum point of the system is spatial dependent on the 3D space. A strategy is proposed to deal with this problem. The experimental results showed that the proposed idea successfully captures the global peak in all the 50 alignment trials for 10 different LD-fiber pairs, regardless of the position and size of the initial simplex.