Patent ID: 7162121

Claim:
An all-optical bi-stable device, comprising: a) a first comparator having a first activating input to receive a first activating signal, a first threshold input to receive a first threshold signal, and a first clamping output, wherein said first comparator is arranged to produce a first high-level clamped output signal at said first clamping output when the first activating signal is stronger than the first threshold signal, and to produce a first low-level output signal at said first clamping output when the first activating signal and the first threshold signal have comparable strengths; b) a second comparator having a second activating input to receive a second activating signal, a second threshold input to receive a second threshold signal, and a second clamping output, wherein said second comparator is arranged to produce a second high-level clamped output signal at said second clamping output when the second activating signal is stronger than the second threshold signal, and to produce a second low-level output signal at said second clamping output when the second activating signal and the second threshold signal have comparable strengths; c) a first optical path between said first clamping output and said second threshold input and a second optical path between said second clamping output and said first threshold input, for creating one of two stable states in which one of said first and second clamping outputs produces one of said first and second high-level clamped output signals, respectively, and the other clamping output produces one of said first and second low-level output signals, respectively; d) at least one tapping device for tapping one of the high-level clamped output signals and low-level output signals from one of said first and said second optical paths, and e) at least one coupling device for coupling an input signal into one of said first and said second optical paths, to flip between said two stable states by converting said first or second high-level clamped output signal into said first or second low-level output signal, respectively.