Patent ID: 7995917

Claim:
A system for chemical identification of a medium comprising: an online laser for generating an online CW carrier, an offline laser for generating an offline CW carrier, the offline CW carrier including a wavelength different from a wavelength of the online CW carrier, a PN encoder for forming a PN encoded word, a PN′ encoder for forming a PN′ encoded word, the PN′ encoded word being orthogonal to the PN encoded word, modulators for, respectively, modulating the online and offline CW carriers with the PN and PN′ encoded words, a medium for propagating the modulated online and offline CW carriers, a receiver configured to detect the propagated, modulated online and offline CW carriers to form a detected signal, a processor configured to correlate the detected signal with the PN and PN′ encoded words, and the processor configured to measure a property of the medium based on the correlated detected signal with the PN and PN′ encoded words.