All-Optical Switch Based on a Fiber-Chip-Fiber Opto-Mechanical System With Ultrahigh Extinction Ratio

We propose and experimentally demonstrate an all-optical switch based on a fiber-chip-fiber opto-mechanical system driven by thermal radiation. The two optical fibers are both designed as movable cantilever structures with a free-hanging length. With injecting pump lights into the opto-mechanical system, the generated thermal radiation between the grating couplers and the optical fibers could effectively move the fibers with displacements up to tens of micrometers. Thus, the optical fibers would completely deviate from the corresponding grating coupler to cut off the optical signal transmission. In the experiment, using light to control light, both ultrahigh switching extinction ratios beyond 60 dB and an operation bandwidth of at least 45 nm have been achieved by taking advantage of the powerful thermal radiation. To the best of our knowledge, this is a record extinction ratio for fiber-based all-optical switch. The significant thermal radiation opens up a new opportunity and solution for all-optical switch. In the future, the significant effect is promising to be used in fully integrated chips to greatly reduce the required pump power. Moreover, the proposed device has many other applications in all-optical systems, such as reconfigurable logic gates.