All-optical switches based on nanophotonics

The all-optical switch (AOS) is the basis of digital optical information processing, and is a basic device of future all-optical communication, computing, and networks. Since the laser appeared, the AOS has been studied for more than 40 years，but no practical devices have been developed so far. The main reason is that the nonlinear-optics based AOS presents difficulties which are hard to overcome. Recent research shows that nanophotonics and superfast photonics may be able to overcome these difficulties. In this paper we will describe the progress over nearly ten years in the investigation of AOS's based on nanoscale waveguides and nanophotonic materials,some all-optical switches have already achieved the specifications required by current applications, with a switching power on the order of milliwatts and switching time below nanoseconds.