**5. Further improvement of the switch speed**

In the turbo-switch structure, an extra SOA2 is cascaded following the SOA1, acting as a highpass filter to filter out the slow response associated with the SOA carrier lifetime. In such a way, the overall operation speed of the turbo-switch device has been demonstrated several times faster than that of a single SOA. A straight-forward idea is that, if more SOAs are cascaded after the turbo-switch, is there any further improvement to the operation speed?
