Physical-parameter design in 2-D MEMS optical switches

Free-space micromachined optical switching technology has emerged as a promising candidate for the transparent optical cross connects that are needed in next-generation optical transport networks. This paper deals with the system design of two-dimensional (2-D) microelectromechanical system (MEMS)-based cross connects. In particular, we propose a method, applicable to any kind of 2-D MEMS switching architectures, which finds the best choices of the basic geometrical parameters of the device (such as mirror radius and beam-waist size) allowing the achievement of given insertion-loss and differential-loss target values for the overall switching matrix. Our proposal is based on a widely used model of the loss mechanisms in a 2-D MEMS switch, keeping Gaussian-beam divergence and free-space/fiber mode mismatching into account. By adopting the proposed design technique, we compare various 2-D MEMS architectures recently proposed in the technical literature in terms of cost and feasibility of large port count optical switches.