Configurable demultiplexing circuits for intensity-based multiplexed optical communications

A repeating cell comprising:

• a first optical signal detection unit including:
• first and second optical attenuators arranged in parallel to each receive a respective portion of an input optical signal, wherein the first optical attenuator is configured to attenuate its respective portion of the input optical signal by a first amount of attenuation and produce a first attenuated output, and the second optical attenuator is configured to attenuate its respective portion of the input optical signal by a second amount of attenuation and produce a second attenuated output, wherein the first amount of attenuation is different than the second amount of attenuation;
• first and second optical detectors arranged in parallel to respectively receive the first and second attenuated outputs and respectively produce first and second detector outputs, wherein by default the first and second detector outputs represent a logic low state, and wherein the first detector output represents a logic high state when the first attenuated output has sufficient optical intensity to trigger the first optical detector, and the second detector output represents a logic high state when the second attenuated output has sufficient optical intensity to trigger the second optical detector, the first and second amounts of attenuation effectively defining a first range of optical intensities for detecting when the input optical signal has a component signal with an optical intensity representing a logic high state;
• and
• a first exclusive-or (XOR) logic circuit arranged to perform an XOR operation on the first and second detector outputs to produce a first detection output, the first detection output representing a logic high state only when the first and second detector outputs represent different logic states;
• a second optical signal detection unit including:
• third and fourth optical attenuators arranged in parallel to each receive a respective portion of an input optical signal, wherein the third optical attenuator is configured to attenuate its respective portion of the input optical signal by a third amount of attenuation and produce a third attenuated output, and the fourth optical attenuator is configured to attenuate its respective portion of the input optical signal by a fourth amount of attenuation and produce a fourth attenuated output, wherein the third amount of attenuation is different than the fourth amount of attenuation;
• third and fourth optical detectors arranged in parallel to respectively receive the third and fourth attenuated outputs and respectively produce third and fourth detector outputs, wherein by default the third and fourth detector outputs represent a logic low state, and wherein the first detector output represents a logic high state when the third attenuated output has sufficient optical intensity to trigger the third optical detector, and the fourth detector output represents a logic high state when the fourth attenuated output has sufficient optical intensity to trigger the fourth optical detector, the third and fourth amounts of attenuation effectively defining a second range of optical intensities for detecting when the input optical signal has a component signal with an optical intensity representing a logic high state, wherein the second range of optical intensities is different than the first range of optical intensities effectively defined in the first optical signal detection unit;
• and
• a second exclusive-or (XOR) logic circuit arranged to perform an XOR operation on the third and fourth detector outputs to produce a second detection output, the second detection output representing a logic high state only when the third and fourth detector outputs represent different logic states;
• and
• a third exclusive-or (XOR) logic circuit arranged to perform an XOR operation on the first and second detection outputs to produce a repeating cell detection output.