A Comparative Review of MEMS-Based Optical Cross-Connects for All-Optical Networks From the Past to the Present Day

Micro-electro-mechanical systems (MEMS)-based cross-connects are widely used for all-optical switching in recent optical networks. This paper provides a brief overview of various photonic switching technologies and a detailed review of the working principles, actuating mechanisms, and architectures of MEMS-based optical cross-connects (OXCs) from the last two decades. New approaches, which, potentially, will be adopted in the next generation of MEMS-based cross-connects are also described. The switching MEMS-based cross-connects speed can vary from less than 1 μs to tens of ms depending on the chosen switching mechanism and actuator parameters. This paper describes the various types of actuators used to manipulate the optical signal inside all-OXCs. Optical properties (insertion loss, crosstalk), switching speed, and scalability are also discussed.