Open loop control theory algorithms for high-speed 3D MEMS optical switches

There is a world-wide push to create the next-generation all-optical transmission and switching technologies for exascale data centers. In this paper we focus on the switching fabrics. Many different types of 2D architectures are being explored including MEMS/waveguides and semiconductor optical amplifiers. However, these tend to suffer from high, path-dependent losses and crosstalk issues. The technologies with the best optical properties demonstrated to date in large fabrics (>100 ports) are 3D MEMS beam steering approaches. These have low average insertion losses and, equally important, a narrow loss distribution. However, 3D MEMS fabrics are generally dismissed from serious consideration for this application because of their slow switching speeds (similar to few milliseconds) and high costs ($100/port). In this paper we show how novel feedforward open loop controls can solve both problems by improving MEMS switching speeds by two orders of magnitude and costs by a factor of three. With these improvements in hand, we believe 3D MEMS fabrics can become the technology of choice for data centers. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement