Some exemplary embodiments of one version of the present invention provide an optical switch including: a splitting device having first, second, third and fourth terminals; a nonlinear element; an attenuator; and an optical loop associated with the third and fourth terminals, the optical loop including the attenuator and the nonlinear element, the nonlinear element being displaced from a mid-point of the optical loop, wherein the splitting device is able to receive an input signal via one of the first and second terminals and an activating signal via one of the first and second terminals and to provide an output signal at one of the first and second terminals in response to the activating signal. In exemplary embodiments of alternative versions of the present inventions, the optical switch may include a threshold device. In some versions, the optical switch may be operated with a continuous wave or a pulse based activating signal.