Patent ID: 7253906

Claim:
An optical multiplexing apparatus comprising: a tunable light source for providing a light beam, the beam having a wavelength that varies periodically through a range of wavelengths at a sweep frequency rate, a first splitting means for splitting the light beam into a signal beam and a reference beam, a second splitting means for splitting the signal beam into at least four sub-beams; means for imparting a distinctly different polarization state to each of the sub-beams in order to associate each of the sub-beams with a different polarization state, means for recombining the sub-beams with different polarization states into a single optical beam; means for interfering the single optical beam with the reference beam in order to obtain an output light signal, having an amplitude which varies in time; and means for detecting the output light signal and resolving the output signal into frequency components thereof; wherein the time delay for each the sub-beam is selected such that a unique frequency component of the output light signal is associated with each one of the different polarization states; and wherein the at least four sub-beams comprise four sub-beams with four different polarization states comprising linear horizontal, linear diagonal, linear vertical, and right-hand circular.