Ultrafast operation of Si thermo-optic switch using differential control method

To realize fast switching of a few mu s and low-power consumption, we apply a differential control method to a thermo-optic Mach-Zehnder interferometer optical switch loaded with a direct-current injection-type phase shifter using multimode interference. We achieve ultrafast switching of several tens of ns, which is considerably higher than the conventional switching speed. With differential control, we demonstrate extremely fast optical switching with T-rise = 36 ns and T-fall = 24 ns. This method can be widely applied to similar devices and can contribute significantly to the speedup of other thermo-optic switches. (c) 2022 The Japan Society of Applied Physics